Motivation

As Kant said (more or less), "there are three irreducible faculties of mind: knowledge, feeling, and desire". Having covered the cognitive psychology of knowledge, and the affective psychology of emotion, it remains for us to say something about the conative psychology of motivation.

The problem for the psychology of motivation can be stated simply:

Why do people engage in various activities -- bowling, fly fishing, marathon running, writing poetry, playing the recorder, whatever? Even when we don't do these things particularly well?

Psychologists often explain people's behavior in terms of their motives, but this is something that all of us do in the ordinary course of everyday living.

In fact, motives are a critical ingredient in Western concepts of law and justice. In the Anglo-American legal system, there are two elements of every crime:actus rea (Latin, "the doing of the thing) and mens rea ("the mind of the thing"). People may do bad things, but they haven't committed a crime unless the evil deed is accompanied by evil intent. This is the basis of our modern insanity defense.

However, in the wake of the terrorist attacks of September 11, 2001, the legal system has begun to shift somewhat, from the traditional law-enforcement focus on punishing crime that have already occurred to a more preventative, or perhaps pre-emptive, focus on preventing -- at least crimes of terror -- to begin with. Now, in both America and England, as well as elsewhere, individuals can be prosecuted for wanting to commit crimes, even if they haven't yet done so, or engaged in any overt acts toward committing a crime (such as buying weapons). In this new era of preventive and pre-emptive law enforcement, the government will attempt to establish the intent to commit a crime based on evidence of preparatory behavior, such as training, but also through evidence of beliefs that suggest support for, and an inclination to engage in, terrorist acts. This brings the law squarely into the psychologist's territory: how can we know other people's desires, how does motivation work, and what is the relation between motives and behavior?

Defining Motivation

A motive may be defined as an internal state that causes the organism to initiate, choose, or persist in behavior that is directed toward, or away from, some goal. The motivational state of hunger causes us to eat, the motivational state of thirst causes us to drink, and so on. We usually think of motivational states in terms of drives,needs,wants,goals, and desires. These terms do not all mean quite the same thing. We can need something that we don't really want; and in this consumer-oriented society, we can want a whole lot of things that we don't need. But psychologists, like everyone else, tend to use these terms pretty much interchangeably.

Approach and Avoidance

Given the definition of motivation offered above, it would seem that the two basic motives are approach and avoidance -- paralleling the two basic emotional states, pleasure and pain (broadly construed).

Gray (1970) proposed that motivation has its physical basis in two different brain systems.

Early in the history of psychology, motivated behavior was often ascribed to instincts. Thus, for example, eating was explained in terms of an instinct to eat. Such explanations were unsatisfactory, because in the absence of independent evidence for the instinct they seemed circular: Why does the animal eat? Because of an eating instinct. How do we know there is such an instinct? Because it eats.

Later, as a result of the behaviorist revolution initiated by Watson and consolidated by Skinner, motivational constructs were banished from psychology altogether, as too mentalistic. In stimulus-response terms, eating was the response to the stimulus of food-deprivation, and drinking was the response to the stimulus of water-deprivation. No internal states were needed to explain the behavior; the organism could be treated as if it were "empty", or devoid of motives, goals, needs, wants, or desires.

Even during the heyday (or dark days) of functional behaviorism, however, there were psychologists who adopted behaviorist methodologies, but still considered motivational states to be important for the explanation of behavior. For example, in a famous formulation, Clark L. Hull (then at Yale University) offered a simple formula to explain behavior:

Hull's theory got a lot more complicated, and in the final analysis it didn't work (Gleitman, a student of the cognitive learning theorist Edward C. Tolman, was one of the researchers who, along with his colleagues Jacob Nachmias and Ulric Neisser, proved it wrong -- or, at least, internally inconsistent). But Hull's theory is important in historical terms, because it attempted to keep alive the notion that motivational states were important in the explanation of behavior.

The cognitive revolution made it safe for psychologists to talk once more about the role of internal mental states in the determination of behavior. But even before the cognitive revolution, great advances in understanding the physiological basis of hunger, thirst, and other biological motives helped advance a psychology of motivation, by showing how motivational states like hunger, and behaviors like eating and drinking, were related to physiological states of the organism. The study of motivation goes beyond biological motives such as hunger and thirst, but that is where our story begins.

Motivation and Emotion

Motivation and emotion are related. Obviously, approach and avoidance behavior can be motivated by positive and negative emotion -- or at least the anticipation of it; successful approach may be followed by positive affect; and successful avoidance can eliminate negative affect. Accordingly, some theorists treat emotion and motivation together.

On the other hand, approach doesn't always go with pleasure, and avoidance doesn't always go with pain. There are some people out there who like pain, a condition called masochism. And there are other people who seem to be motivated to inflict pain on themselves, as in the "cutting" and other self-injurious behaviors sometimes encountered in the clinic.

In this course, we will follow the Kantian doctrine, that both emotion and motivation are irreducible faculties of mind, and treat them separately.

Homeostatic Regulation

Many motivational processes are based on what the 19th-century French physiologist Claude Bernard called homeostatic regulation -- that is, the regulation of the organism's internal environment or physiological state. This is accomplished by a set of physiological mechanisms by which the body maintains a constant internal environment, despite changes in the external environment -- mechanisms that are so precisely tuned that Walter Cannon, an American physiologist, called them "the wisdom of the body" (1932).

The basis of homeostatic regulation is negative feedback, which means that changes in the environment instigate actions that have the effect of stopping, or reversing, those very same changes. A familiar example is a thermostat: when a room gets too cold, the thermostat turns on the heat, and then turns off the heat when the room is restored to its proper temperature; and when the room gets too hot, the thermostat turns on the air conditioning (or, at least, a fan or evaporative cooler) and then turns the air off when the room is cooled down. (In positive feedback, a change in the environment instigates a process that magnifies the change. A familiar example is feedback at a rock concert, where a microphone picks up sound from a speaker and feeds that sound back into the amplifier, creating screeches and wails).

Note that, as with the positive and negative reinforcement discussed in the lectures on Learning, positive and negative feedback have technical definitions that depart somewhat from the use of these terms in ordinary language.

The Autonomic Nervous System

We have already seen one example of homeostatic regulation by negative feedback: the antagonistic relation between the sympathetic and parasympathetic divisions of the autonomic nervous system. In response to an environmental stressor, the sympathetic nervous system activates the body, preparing it for flight or fight, to tend or befriend. This drains bodily resources (like blood sugar), leading the parasympathetic nervous system to kick in to dampen sympathetic activity, slowing the drain of resources. After the stressor has disappeared, the parasympathetic nervous system continues to operate, restoring things to their optimal levels. Thus, the parasympathetic nervous system supplies negative feedback to the sympathetic nervous system.

Hunger

Hunger, and the eating behavior that it stimulates, operates on homeostatic principles, based on mechanisms that keep track of body weight and glucose (blood sugar).

There are also glucoreceptors in the hypothalamus. In the classic dual-center theory of feeding, the lateral portion of the hypothalamus serves as a "go" center for feeding, initiating eating behavior when body weight drops below normal levels, while the ventromedial portion of the hypothalamus serves as a "stop" center, terminating eating when body weight climbs too high.

The existence of glucoreceptors in the liver, digestive system, and hypothalamus exemplifies Charles Sherrington's notion of interoception. Afferent impulses run from various internal bodily organs to the central nervous system to provide information about the state of these organs -- how much glucose is in the bloodstream, for example. Technically, these are sensory impulses, even though we are not conscious of these sensations.

Another approach to understanding hunger and feeding focuses on calories and body weight (perhaps body mass), rather than blood sugar. According to a highly popular theory, organisms will consume just enough calories to maintain their body weight around a genetically determined set point.

Note that by "set point" we do not mean some medically determined "optimum" weight, such as a body-mass index of 24 (or whatever). Everybody has their own set point, determined in large part by genetics (family history). Some people have very low set points, and are predisposed to be thin. Others have higher set points, and are predisposed to be fat. But body weight is not all in the genes. Changes in the environment, like the food supply, can make people thin or fat even though they might have "average" set points under terms of their normal diets. Moreover, changes in behavior (like exercise) can also alter set points.

Another variant on set-point theory is stated in terms of calories, not body weight or body mass. According to this variant, the organism homeostatic regulation acts to maintain a certain level of daily caloric intake.

But whether we're talking about glucose or body weight, the liver or the hypothalamus, it's all homeostatic regulation by negative feedback.

Thirst

A similar account can be given of thirst. The feature of the internal environment that is regulated by drinking is the concentration of salt in intracellular fluids. When cells become dehydrated, or the concentration of salt inside cells gets too high, the organism is stimulated to drink until the proper levels of hydration are restored.

In another instance of the dual-center theory, Yuki Oka and his colleagues at Columbia University have discovered a particular brain structure, the subfornical organ (SFO), situated -- as its name implies -- in the midbrain on the ventral (lower) surface of the fornix -- which seems to be involved in the regulation of drinking.  Interestingly, the SFO lies outside the blood-brain barrier, in an ideal position to detect fluid levels in the bloodstream.  The  SFO contains both excitatory and inhibitory neurons.  Oka et al. found that stimulating the excitatory neurons caused mice to initiate drinking, and continue drinking water (but nothing else) for long periods; stimulating the inhibitory neurons caused a substantial (though not complete) reduction in drinking.  

According to the double-depletion hypothesis, there are actually two different kinds of thirst. One controls intracellular fluids, while a similar one controls extracellular fluids, as in blood plasma.

In cases of over-hydration, where there is too much water inside or outside cells, the organism will stop drinking for a time.

Thermoregulation

And also of body temperature. For humans, normal body temperature is 98.6^o (for some individuals, it's a little lower or higher, which is where the movie Body Heat got its title from). When an animal's body temperature gets too high, the parasympathetic nervous system initiates a number of behaviors, including vasodilation (which brings circulating blood nearer the surface of the body, where it can be cooled); also sweating and panting, which have the effect of lowering body temperature.

When body temperature gets too low, the same system initiates vasoconstriction, which keeps circulating blood closer to the body's core.

Although thermoregulation is often accomplished by means of such autonomic activities as vasodilation and vasoconstriction, it can also involve overt behavior mediated by the skeletal nervous system. For example, when cats get chilly, they'll curl up on a radiator or heating vent to get warm. And when they get too warm, they'll move off until they cool down.

Not Just Homeostasis

Hunger, thirst, and body temperature exemplify homeostatic regulation via negative feedback, but there is more to these motives than that. We don't eat just to restore body sugars, and drink to restore ell fluids.

As R.S. Woodworth (1918) put it, motivation is about "the struggle for existence", but it's also about "the joy of living".

Eating and drinking are also social behaviors: we engage in them as ways of being with people, and we also do them when other people are doing them.

There is also an emotional overlay to eating and drinking. We often eat and drink when we're sad, for example.

And there's also a perceptual-cognitive overlay to eating and drinking. We can become hungry and thirsty simply by being in the presence of food and drink. A study by Rozin et al. (1998) showed that amnesic patients, who cannot remember recent events, continued eating when served several meals in succession, even though they had ingested their "fill" of calories. They forgot they just had eaten lunch, and they ate (another) lunch because it was lunchtime, and the fact that it was lunchtime, and food was being offered, made them hungry.

There's also evidence that imagining eating can make you less hungry -- or, at least, eat less.  Morewedge et al. (2010) asked subjects to imagine eating 30 M&M candies, or 30 cheddar cheese cubes.  When they were later offered some candies or cheese cubes to eat, they consumed fewer pieces than a control group.

Note: Imagination doesn't always reduce consumption.  In variations of the famous "Stanford Marshmallow Test", discussed at length in the lectures on Personality and Social Interaction, imagining the consummatory qualities of a preferred treat decreased the subjects' ability to delay gratification.  So, there are some details to be worked out here.  Still, the point is that hunger, or at least eating behavior, isn't totally regulated by homeostatic mechanisms.

And sometimes we eat simply because "it's time" to eat. Once, when I was on a train from Chicago to Ann Arbor, I sat behind an elderly couple. For reasons known only to God and Amtrak, the train routinely stopped just outside the rail yards in Chicago, and stayed there for a long period of time. Eventually, the woman asked her husband if he wanted to go to the cafe car to eat. He replied that it was only 11 AM, and it wasn't time to eat. She told him that they had already entered the Eastern Time Zone, and so it was really noon. The husband got right up and they went to get lunch.

The point is that there's a difference between needing to eat, as a matter of sheer survival, and wanting to eat -- to help some with other issues (like depression, for instance), or simply because we like eating. Somewhere, Plutarch quotes Socrates as saying that "Bad men live that they may eat and drink, whereas good men eat and drink that they may live.". But that may be going too far!

In fact, behavioral neuroscientists have begun to think that eating is regulated by two quite different systems:

According to this view, eating in obese people is regulated (if that's the word) by the hedonic system, which is unconnected to, and basically ignores, the homeostatic system.

Beyond Homeostasis

Drive theories, like Hull's, posit that motivation is based on needs, or "irritations", that we try to reduce.  Homeostatic theories, similarly, posit that behavior is motivated by the need to restore bodily states to optimum levels.  Hunger and thirst can be thought of as "irritations" in that sense.  While hunger and thirst emphasize the role of homeostatic regulation, perhaps in parallel with other processes (like hedonic eating) other motives do not seem to involve homeostasis at all.

Aggression

For example, aggressive behavior is stimulated by the presence of external threats, and by high levels of testosterone in the bloodstream. But the goal of aggression is not to reduce testosterone levels: it's to defend one's territory against competition.

Mating

Similarly, in nonhuman animals mating behavior -- OK,sex -- is tightly regulated by sex hormones, estrogen in females and testosterone in males, and occurs only at certain points in the female estrus cycle. After ovulation occurs, the female rat will be receptive to overtures from males, and will even signal to potential partners that she is willing to mate. But at other points in the cycle, the same female will vehemently reject the same male if he tries to mate with her. As with aggression, mating behavior is under hormonal control, but the behavior isn't has no effect on hormone levels -- they rise and fall naturally, as part of the estrus cycle, no matter what the animals do.

Actually, that's not quite true. The female rat's courtship behavior actually triggers the release of testosterone in the male, and copulation will also trigger the release of progesterone in the female, increasing the likelihood that the fertilized ovum will be implanted in the uterus. But neither of these effects represent homeostatic regulation, which is the basic point: not all motives work by homeostasis.

Of course, there are other factors involved in mating. Just as male animals will compete among themselves for the prize of mating, their female counterparts are selective about whom they will mate with.

It is important to point the obvious, which is that human sexual behavior is, to a great extent, freed from hormonal control. That is to say, humans mate regardless of whether the hormonal circumstances are right for reproduction. Sex among humans is motivated behavior, but it's not necessarily motivated by rising hormone levels; it's also motivated by feelings of pleasure, affiliation and intimacy that we get from sex, and even sometimes by power -- motives that play little or no role in the sexual behavior of nonhuman animals (with the possible exception of bonobos, or pygmy chimpanzees).

Human sexual behavior does not entirely escape biology, however. Evolutionary psychologists have argued that men tend to select mates in such a way as to maximize reproductive success -- looking for cues, such as a 7:10 waist-to-hip ratio, or body symmetry, that indicate that a woman is healthy and has good childbearing capacity. They also argue that women are more selective than men about whom they will mate with, because they bear the biological burden of childbearing. Accordingly, they argue, men prefer young, attractive partners, while women prefer partners with high social status. Men, who don't bear the costs of reproduction, happily mate with lots of women; but women, who do, tend to mate with very few men. Men get jealous when their mates are sexually unfaithful, because it means that they can't be certain that they are raising their own offspring. Women get jealous when their mates are emotionally unfaithful, because they are looking for security for themselves and their children.

Hey, don't yell at me: I didn't say it, I'm just reporting the work of others.

Actually, my view is that the arguments of the evolutionary psychologists are seriously wrongheaded, in large part because they assume that (a) human nature hasn't changed since what they call the Environment of Early Adaptation in which modern humans evolved -- namely the African savannah of the Pleistocene Era (long, long, ago and far, far away); and (b) that the primary purpose of human sexual behavior is reproduction. But human nature has changed, and the primary purpose of sex isn't reproduction.

Cultural evolution proceeds at a faster pace than biological evolution, and it's simply a fact that sexual preferences change from time to time and vary from culture to culture. Renaissance paintings, for example, are filled with naked women who are, for want of a better term, Rubenesque. And even now, there are American subcultures in which men prefer women "with a little meat on their bones" instead of scrawny supermodels. The historical records of the Miss America beauty pageant show that the average BMI of contest winners declined progressively from the 1920s to the 1990s, and has begun to increase again. These are all cultural changes, and they have nothing to do with behavioral evolution.

Moreover, it's simply a fact that human sexual behavior serves purposes other than reproduction. That's why so many people, even married people, use condoms and other means of birth control. That's why people engage in sexual behaviors, like oral sex, that have no reproductive purpose. When the Monica Lewinsky scandal broke during the administration of President Bill Clinton, evolutionary psychologists fell all over themselves explaining Clinton's behavior -- "Hey, he's just a guy, he wants to mate with a lot of women, especially young, fecund ones, and produce a lot of offspring!". Never mind that Bill and Hillary had just one child together; for all his alleged philandering, Bill never produced another child; and the affair between Bill and Monica was confined to fellatio. So much for explaining Bill's behavior in terms of evolutionary psychology.

Of course the biological motives are determined, to some extent, by genes, hormones, and evolution, and serve obvious biological purposes. That's why they're called biological motives. But even hunger, thirst, aggression, and sex have sources, and meanings, that go beyond biology. Motivated behavior is influenced by the meaning of both the motive and the behavior, and it's shaped by the sociocultural context in which it takes place.

At least for humans, and that's where our primary interest lies.

The Reward System in the Brain

Hunger and thirst, and being too cold or too hot, are unpleasant, and it's not surprising that we are motivated to reduce or eliminate these conditions.  But we also seek pleasure (as, for example, in mating), and such motives appear to be based in what is known as the reward system in the brain. 

In the early days of behavioral neuroscience, James Olds and Peter Milner (1954; see also Olds, "Pleasure Centers in the Brain", Scientific American, 1956), reported the discovery of of a pleasure center in the brain.  Working with rats, these investigators implanted constructed a special operant chamber (aka "Skinner box") such that, when the animals pressed a bar, a small burst of electrical current (rather than a food pellet) was delivered to their brains through microelectrodes implanted in the so-called "septal" portion of the brain, which is part of the limbic system in the region that divides the two hemispheres.  The rats learned to bar-press for the electrical jolt, just as other rats learned to bar-press for food.  And, in fact, the rats preferred electrical self-stimulation to food!  It sure looked as if stimulating the septal area produced feelings of pleasure. 

We now know that things are a little more complicated than this.  For one thing, pleasure isn't mediated by a single center, but by an entire system or circuit of cortical and subcortical structures, as illustrated by this graphic (from "The Addicted Brain" by Fran Smith, National Geographic, 09/2017).  What all of these structures have in common is that they are heavily laced with dopaminergic cells, which make use of the neurotransmitter, dopamine.  For example, some of Olds's rats worked hard for brain stimulation, but others didn't.  It turns out that those who were rewarded by brain stimulation had their microelectrodes planed in these dopaminergic areas.  So, rather than there being a "pleasure center", or even a "pleasure circuit" in the brain, it looks like dopamine is a sort of "pleasure chemical", in that its release caused the sensation of pleasure.  But even that isn't quite right, because it turns out that what controls dopaminergic activation is the expectation of reward.  When an animal receives a reward that is unexpected, dopaminergic activity increases.  Dopaminergic activity decreases if the animal does not receive an expected reward.  But these are details you'll learn more about if you take a specialized course in neuroscience -- by which time the story will probably have been refined still further.

The operation of the dopaminergic reward circuit can be illustrated by looking at the process of physiological addiction (and probably other addictions, too, including addictions to video games!).  All addictive drugs, such as heroin or cocaine, cause an increased flow of dopamine.  To make things worse, objects and events associated with these drugs, such as hypodermic needles, can also result in increased dopamine flow by virtue of classical conditioning. 

One influential model of the addiction process is known as impaired response inhibition and salience attribution (I-RISA; Goldstein & Volkow, Am. J. Psychiat., 2002).   The dopaminergic system plays a major role in I-RISA, but the model is much more complex than this.  Moreover, as I'll go into more detail later, there's every to think that, in the final analysis, addiction is less a problem of seeking pleasure and more a problem of avoiding pain.  But for now, let's just focus on the pleasure and reward.

Let's begin by looking in more detail at the role of dopamine in pleasure and addiction.  As noted, dopamine is a major neurotransmitter.  As with any neurotransmitter, a dopaminergic neuron contains dopamine.  When a presynaptic dopaminergic neuron fires, dopamine is secreted by the terminal fibers, and carried across the synapse by dopamine transporters, and taken up by specialized dopamine receptors located on the dendrites of the postsynaptic dopaminergic neuron.  After the postsynaptic neuron fires, the dopamine transporters return excess dopamine to the presynaptic neuron. 

When an organism experiences, or even anticipates, a pleasurable activity, this psychological state is accompanied by the release of dopamine.  This flow is modulated by various addictive drugs.  For example:

• Heroin blocks dopamine inhibitors in the ventral tegmentum, another structure in the limbic system which is the actual source of dopamine, effectively increasing the amount of active dopamine in the neurons of the brain's reward system.
• Methamphetamine loosens the normal controlled flow of dopamine into the synapse, resulting in increased flow of the neurotransmitter into the synapse.
• Cocaine interferes with the process of synaptic reuptake, leaving excess dopamine in the synapse.

Any way it happens, the result is a flood of dopamine into the system.   But that's not all that happens, according to I-RISA, because dopamine doesn't just flow.  In particular, it flows to other structures in the reward system, affecting the activity of these pleasure hot spots:

• The dorsal striatum identifies patterns of behavior associated with pleasure.
• The prefrontal cortex mediates visual imagery associated with the addictive substance.
  
• The amygdala is activated by memories of pleasure -- and of craving.
  
• The orbitofrontal cortex mediates the sense of pleasure and gratification of desire.
• The nuclelus accumbens magnifies feelings of pleasure.
• The ventral palladum, if damaged, can transform pleasure into disgust.
• The brain stem generates the bodily sensations associated with pleasure. s
  

 All of this happens when organisms ingest addictive drugs.  But, according to the proponents of I-RISA, it also happens with other pleasurable activities, such as eating and having sex, gambling and playing video games, and so it can happen that people become addicted to these activities as well.  Wherever there's pleasure, according to I-RISA, the dopamine system is involved, and the potential for addiction is there as well.  However, that may be putting too much emphasis on the pleasure component of the addictive cycle.  It's not always clear whether non-drug "addictions", if that's what they are, involve the phenomena of tolerance and withdrawal that seem so central to the definition of addiction.  I'll have more to say on this matter later in these lectures.

Moreover, it may be that different kinds of pleasure recruit different brain systems, in addition to the standard dopamine-based reward system -- or, for that matter, .  In particular, some theorists in neuroesthetics, argue that esthetic responses to visual art and architecture, literature, music, and the like also involve brain circuits related to memory, the sense of self, and other cognitive functions, which generate "high-level pleasure" (see "Pleasure Junkies All Around!" by Julia Christensen, Proceedings of the Royal Society B, 2017).  And, in fact, high-level pleasure may not involve the dopamine reward system at all.  After all, people don't appear to become addicted to music or art the way they can become addicted to sex and drugs.

For more on the varieties of pleasurable experience, and their neural bases, see How Pleasure Works: The New Science of Why We Like What We Like (2010) by Paul Bloom.

 

Primary and Secondary Reinforcement

Biological motives like hunger and thirst are the basis of primary reinforcement. Recall Thorndike's laws of learning: according to the Law of Readiness, behavior is activated by the organism's motivational state, which serves as the basis of reward; and according to the Law of Effect, behavior is learned because it is rewarded in a manner that leads to the satisfaction of that state.Primary reinforcers satisfy basic biological motives, such as hunger, thirst, and sex.

Secondary reinforcers, are derived through their association with primary reinforcers, through a process of conditioning. A rat who has been rewarded with food in a white goal box, but not a black goal box, will run to the white goal box even in the absence of reward. Apparently, the white goal box has taken on reinforcing properties by virtue of its association with the food reward. This is what is also known as a conditioned reinforcer. As another example, monkeys will work for grapes, which is a highly preferred food, but they will also work for poker chips which they can exchange for grapes at a later time.

In the human case, the classic example of a conditioned, secondary reinforcer is money: it's no good on its own, just a piece of paper or metal, but we want it because it allows us to satisfy our primary motives. Academic grades are also secondary reinforcers -- they're reinforcing because they stand for something else.

But it's not just money. Emotion can also serve as a secondary motivation. That is, by virtue of conditioning, we can come to fear previously neutral objects, and try to escape or avoid them. Classical fear conditioning is an example of how an emotional response can be acquired through learning. And instrumental escape or avoidance learning are good examples of how motives -- to avoid previously neutral objects or stimuli -- can be acquired through learning.

In the same way, we can come to enjoy previously neutral objects, and try to approach or obtain them.

The Premack Principle

We usually think of reinforcement as a stimulus, like food or money, but behaviors can also be reinforcing.  The Premack Principle states that high-probability behaviors can reinforce low-probability behaviors (Premack, Psychological Review, 1959).  In one experiment, young children were given the opportunity to engage in one of two activities, either playing pinball or eating candy.  Some children preferred to play pinball, others to eat candy.  Premack then made the high-probability activity contingent on the low-probability one.  That is, children who preferred to eat candy had to play pinball first, and vice-versa.  The frequency of the less-desired activity subsequently increased.  People can be motivated to perform an activity if they are rewarded with another, more highly desirable activity, later on.

Parents intuitively understand this principle, which is why they tell their children that they must eat their broccoli before they can have dessert.  Behavior therapists will also use the Premack Principle to change the behavior of their patients. 

The Premack principle works for monkeys (which is where Premack first discovered it), and it works for college students, too -- for example, when you tell yourself that you can't go to the movies until you complete your calculus assignment.

The Opponent-Process Theory of Acquired Motivation

Some secondary motives are acquired through learning, but other secondary motives appear to reflect innate physiological processes.

One consequence of the antagonistic relationship between the sympathetic and parasympathetic nervous system may be the peculiar temporal dynamics of affect. The person's initial response to an arousing event is an increase in positive or negative emotion: happiness, sadness, or whatever. But as the event continues, the emotional state doesn't remain at this initially high level; rather, the emotional response decreases, and then stabilizes. When the arousing event terminates, the emotional state doesn't just go back to zero. Rather, the person experiences the sudden onset of the opposite emotional state. Fear is replaced by happiness, pleasure is replaced by sadness. This opposite hedonic state gradually diminishes, and the person returns to baseline (i.e., zero).

This pattern is explained by the opponent-process theory of acquired motivation, proposed by Richard L. Solomon of the University of Pennsylvania. An acquired motive is a drive that is learned through experience. Hunger, thirst, and sex are innate drives. But love for a particular person, or the fear of a phobic object, are in some sense learned. The basic idea of the opponent-process theory is that each emotional state (call it the A State) automatically generates its opposite (call it the B State). The B State is, therefore, a slave to the A State. The person's emotional experience at any particular moment in time reflects the joint effects of the A and B processes.

The entire pattern may be illustrated with respect to drug addiction, as in morphine or opium. The user's initial dose of morphine produces a feeling of intense euphoria, or high, which we will label the A State. As the morphine wears off, the high is replaced by the negative feelings of withdrawal, which we will label the B State. Repeated doses, however, lead to tolerance: it takes more of a dose to achieve the level of the initial high. This is because the slave B state is strengthened by the repeated elicitation of the A State by the drug. B counteracts A, so it takes correspondingly larger doses of to overcome B and achieve the high of A. But, paradoxically, each dose strengthens the B state. This initiates a vicious cycle in which the more you dose, the less likely you are to feel the euphoric high, and the stronger will be the negative withdrawal. Thus occurs the paradox of drug addiction: addicts aren't seeking the high anymore; rather, they are trying to avoid withdrawal. If the cycle is perpetuated, the inevitable result will be a lethal overdose. This is because the physiological effect of narcotics is to depress vital functions like heart rate. So, in seeking to achieve a high against the effects of tolerance, the person overdoses to the point of death.THIS OUTCOME IS INEVITABLE IF THE ADDICTIVE CYCLE CONTINUES. SO DON'T START.

If you think about it, something resembling the high, withdrawal, tolerance, and addiction can be experienced while eating potato chips and similar snacks. The first chip (or, more correctly, the first handful of chips) produces a kind of high, but this wears off, resulting in a kind of craving, and then redosing -- another handful, and another, and another until the whole bag is finished. Watch people at the next party. Watch yourself. Physiologically, the addition to salted snacks shows strong parallels to the addition to morphine. This "salted nut phenomenon" is the origin of the old advertising slogan (for Lay's potato chips), "Betcha can't eat just one!".Something similar happens with chocolate.

In fact, David Kessler, former commissioner of the Food and Drug Administration, and former dean of both the Yale and UCSF School of Medicine, has proposed a theory of overeating that relates to the opponent-process theory (in his book,The End of Overeating, 2009). He begins with the observation that some foods, particularly those served by fast-food operations, are almost irresistible -- it's hard to eat just one. Example: MacDonald's French fries. Kessler discovered that these "hyperpalatable" foods typically have extremely high levels of salt, fat, and sugars. This combination is literally addictive, so that -- instead of feeling sated after eating a Whopper Junior and small fries -- we crave even more. As with other addictive substances, this process can be conditioned to environmental cues, so that driving past a fast-food restaurant can stimulate the craving. and it also produces tolerance and withdrawal.

Not only can't you eat just one, but eating just one can initiate the entire cycle of addiction. It's no wonder that obesity is a problem in American society, where salty, fatty, sweet foods are so readily accessible.

Processed foods seem to be especially important to this addictive cycle.  Kelly D. Brownell, the world's foremost authority on obesity, has noted that "We don't abuse lettuce, turnips and oranges.  But when a highly processed food is eaten, the body may go haywire.  Nobody abuses corn as far as I now, but when you process it into Cheetos, what happens?" ("Craving an Ice-Cream Fix" by Tara Parker-Pope, New York times Magazine 08/23/2012).

Here's how, in rough outline, it works.  In response to decreased blood-sugar levels, appetite-stimulating hormones activate the feeding circuits in the hypothalamus, and when those levels are restored appetite-suppressing hormones deactivates these circuits.  The result is the activation and inhibition of eating behavior, just as described earlier in the section on homeostatic regulation.  However, these same hormones act on the reward circuits in the brain, giving rise to the pleasure that goes along with eating -- and the unpleasantness associated eating too much.  it.  However, foods with a high fat and sugar content also release endorphins and other chemicals that act on the brain's reward system independent of appetite and satiety, and promote overeating in the absence of hunger.  This instigates the addictive cycle of tolerance and withdrawal.

Salt, fat, sugar, crunch... which is most important?  The whole quartet delivers a great addictive punch, but some ingredients, it seems are more important than others.  In an experiment, Eric Stice and his colleagues asked teenagers -- yes, you can get paid for doing this! -- to drink milkshakes which were systematically varied in terms of their fat and sugar content; using fMRI, Stice et al. recorded activity in the "reward center" of the brain (American Journal of Clinical Nutrition, 2013).

Interestingly public-health officials are more concerned about fat than sugar, but it appears that sugar paves the road to food addictions and obesity. 

See also:

• "The Food Addiction" by Paul J. Kenny, Scientific American 09/2013), from which the figure is taken.
• "(Salt + Fat² / Satisfying Crunch) x Pleasing Mouth Feel = A Food Designed to Addict" by Michael Moss, New York Times Magazine 02/24/2013, adapted from Moss's book, Salt Sugar Fat: How the Food Giants Hooked Us (2013). 
  
• Moss's 2013 book simply argued that the combination of salt, sugar, and fat triggered he dopamine-based eward system in the brain, making processed foods more appealing to the palate.  His followup, Hooked: Food, Free Will, and How the Food Giants Exploit Out Addictions (2021; reviewed by Daniel Liberman in "The Science Behind Your Need for One More Potato Chip", New York Times Book Review, 03/28/2021; see also "This is Your Brain on Junk Food" by Anahad O'Connor, New York Times, 04/06/2021), continues the theme but adds the punchline: Salt+Sugar+Fat+Crunch=Addiction.  Once again, Moss related how the processed-food industry seeks to maximize its "stomach share".  One neat trick he describes is the manipulation of nutrition labels on food packaging: our household bag of potato chips says that a "serving size" is 13 chips:  Betcha can't eat just one?  Betcha can't eat just 13, either!  It's no accident, he argues, that until recently Phillip Morris, the cigarette industry, owned both Kraft and General Foods. 

On a different scale, the same kind of effect can be experienced by jogger's high, and similar effects of extended aerobic exercise (running, swimming, dancing) on well-trained athletes. The exercise obviously produces prolonged stress on the body -- the less so to the degree that the person is trained for the event. But at the finish line, as the exercise ceases, the athlete experiences exhilaration and euphoria. In this case, the negative State A is gradually replaced by the positive State B.

Something similar happens in sport parachuting (there's actually research on this).

And, for that matter, it happens with professional musicians. In an article on the travails of brass players in the orchestra pit during Wagner's Ring cycle, the author noted:

then, too, just making it to the end of a "Ring" cycle is its own reward. "Every time we get to the last note of "Gotterdammerung," said the Met's Mr. Gemeinhardt [a horn and Wagnerian tuba player in the Metropolitan Opera Orchestra], "there's this little high, because you really feel like you've accomplished something". (See "It Takes Brass to Play the Wagner Tuba" by Barbara Jepson, Wall Street Journal, 04/04/2013.)

Social Motivation

Hunger, thirst, sleep, arousal, mating, and parenting are motives shared by humans and nonhuman animals alike. They serve obvious biological purposes, and their ties to the organism's underlying physiology are fairly well known. Other motives, however, express themselves in characteristically (though not exclusively) human social interaction.

Contact Comfort

One expressly social motive is the bond between infant and its caretaker. The traditional view of bonding is that it is a secondary motive derived from a more basic biological motive, namely feeding. In this view, the infant bonds with its mother because that's how it receives nourishment.

In a classic test of this view, Harry Harlow (1950) studied a group of rhesus monkeys who had been raised alone from infancy. Well, not quite alone. The infants were raised in a cage with two manikins -- one, made out of chicken wire, but supplied with a nipple through which the infant could get milk; the other, covered in terry cloth, but with no nipple. The infants ate from the wire mother, but they cuddled with the terry-cloth one. And when they were frightened (e.g., by a loud noise), Harlow observed that the infants would cling to the cloth mother, from whom they derived no nourishment, but not the wire mother, from whom they got all their food. Harlow concluded that contact comfort was a basic biological drive (at least among primates and other mammals), and not secondary to anything else.

Freud's Drives

Early in the 20th century, for example, Sigmund Freud argued that human experience, thought, and action was motivated by a primitive, biologically based instinctual forces -- and in particular, a sexual drive operating on what he called the pleasure principle.

Freud's fundamental assertion was that personality is rooted in a conflict between instinctual forces on the one hand, and environmental forces on the other. Essentially, Freud's view of personality is that of tension-reduction, based on a hydraulic model. Water in motion exerts pressure on its container, such as a dam or a valve, creating a flow that must be stopped or re-channeled. If it is stopped, it will continue to build up pressure, with damaging results (as when a dam bursts or a pipe breaks). If it is re-channeled, it may be given a controlled release -- thus averting disaster and , perhaps, making a potentially destructive force available for constructive purposes.

As with a waterworks, so it is with personality. Instincts strive for expression, in terms of both thought and action, but they conflict with environmental forces and must be controlled. The person mobilizes various psychological defenses to suppress and transform these instincts, which despite these efforts continue to seek direct or disguised expression. Personality (Freud used the term "character" in the broadest sense) consists of the person's habitual mode of adaptation to this conflict between internal and external forces.

To this basic model Freud adds a developmental theory. He asserted that the nature of the instinctual forces changed as the child matures from infancy to adolescence and adulthood. Also, he held that the individual's adaptation to the conflict is largely determined by events occurring during this time, particularly in early childhood. Without the instincts, however, there would be no personality to develop.

An instinct may be defined as a mental representation of somatic excitation -- that is, as a wish which expresses an innate bodily need. The instinct drives behavior intended to satisfy the physical motive, and thus to reduce the original need. This emphasis on tension- reduction marks behavior as conservative, seeking equilibrium, and regressive, seeking a return to a prior state. In this way an endless cycle of excitement and quiescence emerges, which Freud named the repetition compulsion.

Freud discerned four components to an instinct. Its source is the bodily need which must be satisfied. Its aim is to eliminate the source of the need. Its impetus is the amount of force or energy associated with the instinct. And its object is the behavioral or cognitive activity that will accomplish the aim. The source and aim of an instinct are of course nearly identical, and the former remains constant throughout life. The internal aim, or final goal of an instinct, also remains constant. However, the external aim, the subgoals accomplished on the path to the final goal, can change. The impetus varies as the need is satisfied or frustrated. Finally, the object, like the external aim, can vary according to the individual's developmental stage as well as external constraints.

In his early writings on the subject, Freud (1910) offered a division between the life-maintenance and the sexual instincts. The former consist of biological needs necessary for individual self- preservation. The latter consist of needs, still biological in nature, that are necessary for preservation of the species as a whole rather than any particular member of it. For the individual, the sexual instincts are important only in that they give pleasure. Freud paid little or no attention to the life-maintenance instincts because he observed that they were rarely the source of conflict and anxiety. However, such difficulties did seem to surround the sexual instincts, and Freud gave a special name --libido -- to the energy associated with them.

Upon further reflection, however, Freud noticed that people appeared compelled to repeat unpleasurable as well as pleasurable experiences. For example, a common children's game involves making some favorite object disappear, and then reappear to view. Moreover, adults were often plagued by repetitive traumatic imagery, fantasies, and daydreams of the sort familiar to anyone who has ever been in a serious accident or been embarrassed in public. From these sorts of observations, Freud concluded that his earlier analysis of the instincts was incomplete. The life of the instincts is not, as first appeared, dominated by pleasure. Rather, the fundamental desire that underlies all the instincts is to return to some pre-existing state of quiescence and inactivity. Borrowing a term from Buddhism, Freud referred to this state as nirvana. According to Freud, the desires for pleasure and for quietude are separate and complimentary, but in the final analysis the latter is the fundamental instinct. But taken to the logical extreme, such a statement seems paradoxical. The ultimate state of quiescence for living things is death.

Later in his career, Freud (1924) proposed a new classification of the instincts.Eros included the life and sexual instincts, those concerned with the continuity of life.Thanatos is the death instinct. The names for the instincts are the Greek words for love and death, respectively. According to this new scheme, eros serves thanatos by preserving the organism until it naturally dies. But eros also conflicts with thanatos, transforming the need for self-destruction into a need to destroy others. Freud held that the products of eros are love and sex, while the products of thanatos are hate and aggression.

Freud never fully developed his notion of a death instinct, though World War I convinced him that such a drive toward self-destruction existed. How else to explain how such a mindless orgy of violence and death could occur? While acknowledging the existence of thanatos, then, Freud focused most of his systematic thinking on eros, particularly in its sexual aspects. Our presentation of Freud's theory shares this emphasis. In discussing the sexual instincts, however, it is crucial to bear in mind that Freud defined sexuality very broadly, so that it went beyond intercourse and orgasm to include many different objects, all of which have their source in the desire for pleasure.

And that's about one-third of what you should know about Sigmund Freud -- because, although Freudian psychoanalysis was extremely popular and influential for most of the 20th century, its influence on modern psychology is almost nil. A couple of Freud's assertions are right in the abstract scheme of things, but when it came to details, we now know that he got every one wrong.

Every single one. Which is quite remarkable, when you think that a theory ought to get some things right just by chance. That's what happens when you've got a bad theory. You get everything else wrong.

Murray's Needs

Perhaps the most comprehensive listing of human social motives came from Henry A. Murray (1938), a psychologist who spent his entire career at Harvard. Murray was influenced by Freud, but his theory moved far beyond Freud's narrow focus on biological instincts of sex and aggression. In Murray's "personology" (the label he gave to his theory of personality), individual differences in behavior was determined by the interaction of a personal need with an environmental press. A person's academic, athletic, or business success may be determined by his or her need for achievement, but this need does not determine success directly. Depending on features of the environment, such as family nonsupport, a person with high levels of achievement motivation may nonetheless not succeed in life. By the same token, even "slackers" with low levels of achievement motivation may succeed, at least superficially, by virtue of family characteristics such as wealth, or reputation. As such, Murray's theory can be seen as an early version of interactionism, which we'll discuss later in the lectures on personality and social interaction.

Here is a list of Murray's needs, each characteristically denoted by the abbreviation n (the corresponding abbreviation for press is p). Thus, n Achievement is pronounced "need Achievement", and abbreviated "n Ach". The definitions are from Theories of Personality by C.S. Hall & G. Lindzey (1954).

Murray attempted to measure individual differences in needs by means of the Thematic Apperception Test (TAT), a "projective" device in which subjects were asked to tell stories about ambiguous pictures. These stories were then coded for the frequency with which various need-related themes and images appeared, on the assumption that subjects were "projecting" their own needs onto the characters in the pictures.

That's a lot of needs. In fact, subsequent research focused on only a small number of them, particularly what David McClelland called the three great social motives that drive human social behavior:

Of these, achievement motivation has received by far the most attention, beginning with classic work by McClelland himself, as detailed in his book The Achieving Society. These themes have been pursued by his students.

Maslow's Hierarchy of Needs

Another view to human motivation was offered by Abraham Maslow, one of the pioneers in what has come to be called humanistic psychology. In Maslow's theory, human behavior is motivated by a hierarchy of needs, in which some needs have priority -- they must be satisfied before other, higher needs can be satisfied, or even expressed.

Physiological Needs. At the lowest level of the hierarchy are obvious biological needs, such as hunger and thirst

Safety Needs. After our basic physiological needs have been met, the next need to emerge is for freedom from danger -- both physical danger, but also psychological threats to stability and order.

Love and Belongingness. Once the need for safety has been addressed, then Maslow believed that people were freed to form attachments of various kinds -- to seek friends, find a spouse, and affiliate with various social groupings.

Self-Esteem. The next need in the hierarchy is self-esteem, or the need to feel good about ourselves, and for others to hold good images of us.

Self-Actualization. The highest level of need, in Maslow's view, is "the ongoing actualization of potentials, capacities, and talents, as fulfillment of mission... as an unceasing trend toward unity, integration, or synergy within the person". Or, put another way, referring to people in general, "What a man can be, he must be. This need we may call self-actualization." Nice work if you can get it, and Maslow admitted that few people are lucky enough to be able to devote all their energies to self-actualization -- much less to actually attain it.

Maslow believed that people like Albert Einstein and Mahatma Gandhi actually achieved self-actualization. But for us mere mortals, he provided a kind of checklist of the attributes of self-actualized people:

[F]eelings of limitless horizons opening up to the vision, the feeling of being simultaneous more powerful and also more helpless than one ever was before, the feeling of great ecstasy and wonder and awe, the loss of placing in time and space with, finally, the conviction that something extremely important and valuable had happened, so that the subject is to some extent transformed and strengthened even his daily life by such experiences (Maslow, 1970 p. 164).

For Maslow, as with Freud, these social needs were biologically based -- it is part of our human nature that we strive for safety, love, belongingness, self-esteem, and self-actualization. But these needs are felt, expressed, striven for, and satisfied in an expressly social context.

Maslow's theories were very popular, but like most theories in what became known as humanistic psychology it had little empirical evidence in its favor. For more on humanistic psychology, see the lecture supplements on Personality and Social Interaction.

Recently, Kenrick and his colleagues (2010) have attempted to reconstruct Maslow's hierarchy of needs based on research in an emerging movement known as evolutionary psychology (for more on evolutionary psychology, see the lecture supplements on Psychological Development). Based on the contribution of each motive to reproductive fitness, they constructed a new pyramid of needs, in which each one must be satisfied before the next one can be met:

Note how all of this hangs together from the point of view of reproductive fitness: first, you've got to keep yourself alive; then you've got to join a group which will supply potential mates; then you've got to claw your way up the status hierarchy so that you have a chance to mate; then you have to find a mate and keep her; and then you have to take care of your offspring, or make sure your mate does, until they can go off and propagate their, and thus your, genes on their own.

What's missing, of course, is the most human motive of all (which is why Maslow was called a "humanistic" psychologist) -- self-actualization. Kendrick and his colleagues are explicitly unapologetic about these things. From the point of view of their version of evolutionary psychology, the important human characteristics are those that we share with other species, especially other primates. They don't self-actualize, so that's irrelevant to our lives as well. Self-actualization is irrelevant to reproductive fitness, so it can be consigned to the dustbin of sentimentality. Distinctly human goals -- not just self-actualization, but also more mundane goals like owning a house or having a nice car -- don't figure in the evolutionary scheme of things, and so they're necessarily left out of any hierarchy of motives based on evolutionary theory. Which should tell you something about the limits of evolutionary theory as a framework for human psychology.

Achievement Motivation

McClelland and John (Jack) Atkinson performed a number of studies of n Achievement (McClelland was Murray's protege, and succeeded him as a professor of psychology at Harvard; Atkinson was McClelland's graduate student, and spent his career at the University of Michigan). McClelland's book,The Achieving Society (1961), is a landmark in the study of human social motivation.

In perhaps the most famous experiment on achievement motivation (Atkinson & Litwin, 1960), subjects of high and low n Ach were asked to play a ring-toss game similar to horseshoes or quoits -- with the difference that they were allowed to choose the distance they stood from the target. Subjects low in achievement motivation stood either very close to the target (so that they could not fail), or very far away (as if they didn't not care whether they succeeded). By contrast, subjects high in achievement motivation placed themselves a moderate distance away from the target -- thus creating a situation in which there was some chance of success but also some risk of failure, and in which they could feel good about their success. This outcome is a an example of how people select their environments to match their personalities -- an aspect of the person-by-situation interaction that we'll discuss in the lectures on Personality and Social Interaction.

In another study, Feather (1961) found that subjects high in n Ach persisted longer on an objectively impossible task than did lows.

Fear of Success

McClelland and Atkinson's studies were mostly done with men, because those were the college students who were available to them as subjects at the time they did their research. The question naturally arose as to whether there were any gender differences in achievement motivation. Somewhat surprisingly, Matina Horner (1968), who worked with Atkinson at Michigan, found that college women showed high levels of fear of success -- apparently having internalized a societal stereotype of femininity that conflicted with competence, independence, competition, and achievement. Horner's findings naturally aroused controversy. It should be noted that her findings emerged on the cusp of the feminist revolution in the United States and elsewhere, and it is likely that things would be different if her studies were repeated today. At the same time, it has to be pointed out that even the generation of college-age women that Horner tested included Hillary Rodham Clinton, a woman not known for her avoidance of success. And Horner herself went on to become a professor at Harvard (working with Murray and McClelland), and president of Radcliffe College, which at that time was affiliated with Harvard as its women's division. When Radcliffe was folded into Harvard, Horner became the first president of the Radcliffe Institute, a center devoted to research on women.

Link to an interview with Claude Steele, Vice-Chancellor and Provost at UC Berkeley, in which he discusses stereotype threat as a barrier to achievement.

Entitativity and Incrementalism

The traditional formulation of achievement motivation was as a trait -- it was a psychological characteristic that the individual acquired somehow, either through nature or nurture or both, and that, once established, individual differences were stable across time and consistent across situations. But it turns out that there's a cognitive component to achievement motivation -- that a person's beliefs about achievement motivation are at least as important as his or her level of achievement motivation; and that changing those beliefs can lead to important changes in achievement-related behavior -- and thus, apparently, in achievement motivation itself.

Credit for this discovery goes to Carol Dweck, who was inspired by Seligman's work on learned helplessness (discussed in the lectures on Learning). Recall that Seligman and his colleagues found that dogs subjected to a conditioning regime of uncontrollable shock became unable to learn an avoidance response -- it was as if they had learned that there was nothing they could do to escape or avoid shock. In one early study, Dweck had fifth-graders attempt to solve puzzles posed by two experimenters, whom we'll call George and Martha. Every time they solved a problem, they would get a token, and if they built up enough tokens they could exchange them for a toy. George would give the children problems that most of them could solve; Martha would give them problems that were, in fact, insoluble. But at some point, Martha switched, so that she too gave the children soluble problems. But while the children continued to succeed with George's soluble problems, they generally failed with Martha's. Just as Seligman's dogs acquired the expectation that outcomes were independent of their behaviors, so the children acquired an expectation that they couldn't solve Martha's problems. The point is that motivation -- the desire to achieve -- is not enough; you also have to believe that success is possible. And if you don't believe that success is possible, why should you be motivated to try? Achievement requires both the desire to achieve and the belief that achievement is possible.

Albert Bandura referred to these beliefs as self-efficacy expectations. In social learning theory, reinforcement is not enough to control behavior; the person also has to believe that he or she is capable of engaging in the behavior that leads to reinforcement.

Actually, some of the children did solve Martha's problems, when she started offering them problems that they were soluble. In a further analysis, Dweck discovered that these children tended to view achievement as something that was under their control -- what we call an internal attribution of success. By contrast, the children who continued to fail viewed achievement as something that was under the control of other people, and luck -- an external attribution of success. The "internal" children took responsibility for their own achievement, and persisted even on Martha's insoluble tasks -- with the result that, when Martha switched to soluble tasks, they were able to succeed.

Carol Deck and her colleagues built on this distinction between internal and external attributions to introduce the concept of the individual's implicit theory of competence.

In psychology, an implicit theory is like a scientific theory, but less formal, and less clearly articulated, and less subject to rigorous hypothesis-testing and revision. As Berkeley's own Allison Gopnik has argued so cogently, children are in the business of developing theories about themselves and the world around them (she calls this the "theory theory" of development, and we'll discuss this in more detail in the lectures on Psychological Development).

And this process of theory development, testing, revision, and more testing, continues throughout the life cycle, from birth to death.

In a specific application of the "theory" theory, Carol Dweck and her colleagues (she's now at Stanford) have distinguished between two implicit theories of competence that, in her view, affect children's and adults, motivations to learn.

Dweck and her colleagues have found that entity and incremental "theorists"are differently motivated with respect to earning. For entity theorists, the primary goal is to look smart, while for incremental theorists the primary goal is to actually learn something. And, somewhat paradoxically, praising children for being smart tends to undercut their efforts at school, and thus their performance -- for one thing, it leads them to want to avoid making mistakes. Or they think that they can rely on their raw intelligence to pull them through. Or even: those who are praised for being smart, but know they're really not, will just decide that there's no point to working hard in school. Better to praise the children's efforts: for Dweck, to say someone is "hard working" isn't to damn them with faint praise. And the concept of "overachiever" isn't viable, because it implies that the student is doing better than he or she is supposed to do, given his or her endowment of intellectual abilities. It's not important how smart someone is (or is supposed to be). What's important is how hard one works; and people who work hard may find out that they're smarter than they think they are.

This is important, because Dweck and her colleagues have also found that students who are induced to abandon entitativity, and adopt an incrementalist view instead, actually do better in their studies. They do this by describing the brain as a muscle that gets stronger when it's exercised -- and by teaching them some study skills (like PQ4R). That's because incremental theorists believe that they can do better, if only they tried harder. Entity theorists don't think there's anything they can do -- the best they can do is cover up their insufficiencies.

Now, most of Dweck's research has been done on elementary and middle-school students, and application of her "growth mindset" principles at the college level doesn't always work out. But in one provocative study, Joshua Aronson and his colleagues enrolled Stanford students in a program in which they wrote "pen-pal" letters to local schoolchildren, basically touting the virtues of incrementalism. What was interesting was that the college students themselves began getting better grades, and enjoying their studies more. But things haven't always worked that way. Still, if one of the purposes of a college education is to promote intellectual development, it seems that it would help if both students and their teachers believed that such development was possible.

For more on Dweck's theory of growth mindsets, see:

• Mindset: The New Psychology of Success by Carol Dweck (2006).
• "Two articles by Dweck in Scientific American Mind: "The Secret to Raising Smart Kids" (12/2007-1/2008) and "The Remarkable Reach of Growth Mind-Sets" (01-02/2016).
  

Intrinsic Motivation

So far we've mostly been talking about extrinsic motivation, where the person engages in some activity in order to achieve some goal or satisfy some need -- obtaining a reward or avoiding something unpleasant.Intrinsic motivation is defined as the person's desire to engage in some specific activity without any promise or prospect of reward. Earlier in my life, I ran a lot of 10K road races - not because I had any hope of winning (though I did once come in 3rd, more or less accidentally, because most of the better runners went on to complete a 20k race being run simultaneously), but just because I wanted to, and because I liked it. That "just because" -- that desire to do something just for the pleasure of doing it -- is the key to intrinsic motivation.

Curiosity

One important aspect of intrinsic motivation is curiosity -- the desire to acquire knowledge about things. As with bonding, the traditional view was that curiosity was a secondary motive, derived from other, more basic (and more biological) motives. That is to say, people (and other animals) were only interested in learning how they could satisfy basic needs like hunger, thirst, and sex. Everything else was derived from those basic motives.

This was the view implied by Thorndike's theory of instrumental conditioning. Behavior is activated by motivational states (the Law of Readiness), and reinforced by the satisfaction of those states (the Law of Effect). We learn how to satisfy our basic motives. And anything else we learn is secondary to, and derived from, that.

But we've already seen that Thorndike was wrong on at least one point. Tolman's experiments on latent learning showed that rats can learn even in the absence of reinforcement. In Tolman's view, animals (and people) are motivated to learn about the world around them. To be sure, they can use what they have learned in order to satisfy their basic drives, but reinforcement does not control learning. It controls behavior. For Tolman, the motive to learn is as fundamental, as basic, as the motive to eat or drink (or, for that matter, to have sex).

Again, it was Harry Harlow who showed just how wrong the traditional theory was. In another set of experiments, he presented rhesus monkeys with puzzles consisting of blocks, bolt locks, and similar objects that the monkeys could manipulate. However, learning to unlock a door had no other effect. It did not enable the animal to get food, for example. Harlow discovered that the monkeys would work on the puzzles, and learn to solve them, despite the fact that they were not rewarded for doing so -- at least in the traditional sense of a reward that satisfied some basic, biological motive. The animals simply seemed curious, and derived reinforcement (if that's the appropriate word) simply for figuring out how something worked. When the monkeys were hungry, and solving the puzzle actually led to food, the hunger actually interfered with puzzle-solving (contrary to Thorndike's laws). And when solving the puzzle was rewarded with food, and the monkeys weren't hungry, they simply stored the food for later access, and went back to working the puzzles. Harlow concluded that his monkeys were intrinsically motivated to solve puzzles.

Harlow used to tell the story of leaving his office one night, looking back on his laboratory, and seeing the lights still on. He returned, and shut them off. Walking down the street, he noticed that the lights were on again, and again he returned and shut them off. And again, and again. He discovered that one of his monkeys was caged near the light switch, and was using its tail to turn the light on and off.

I had my own experience, if somewhat more banal, along these lines. When I was a college psychology major, I briefly worked as a research assistant to Prof. Nicholas Longo, who had been a student of Morton Bitterman, a pioneering comparative psychologist. At the time, Longo was preparing a series of experiments on instrumental conditioning in goldfish. The fish would press a submerged paddle with their snouts, and a meal-worm would drop into their tank as a reward. The fish learned to press the paddle to get food. But then we hooked up the paddle to a little light, and it turned out that the fish would press the paddle to turn on the light. At the time, nobody thought that "light" was a basic biological motive for goldfish. Maybe it was. But maybe the fish were bored out of their fish-minds, and got a little cognitive lift from being able to manipulate their environment.

Moving from animals to humans, Donald Berlyne proposed that epistemic curiosity, or the drive to acquire knowledge, was a basic human motive. Similarly, Arie Kruglanski argued that humans were driven by a need for closure -- the need to understand things. These are both basic human motives, not derived from anything more basic. And, if Harlow is right, they're not uniquely human, either.

Undermining Intrinsic Motivation

Although intrinsic motivation is usually construed as an internal, personal determinant of behavior, it can be undermined by situational factors. In one early study, for example, Edward Deci (1971) found that students who had been rewarded for performing a task lost interest in it when the reward was discontinued.

In a classic study by Lepper, Greene, and Nisbett (1973), nursery-school children (these were pupils in the same Stanford nursery school where Walter Mischel did many of his studies of delay of gratification -- you wonder if these kids ever had time to learn anything!) were engaged in a task that is normally enjoyable: drawing on large sheets of paper with felt-tip pens. Before engaging in the task, some children were promised a "Good Player Award" -- basically a big gold star -- for doing so. Other children were promised no reward, and still other children received the reward unexpectedly. Because drawing on big sheets of paper with felt-tip pens is something that is intrinsically motivating, all the kids did it. But later, in a free-play condition where there was no mention of reward, and the children had a lot of choices about what they could do, the children who had received the reward for drawing spent less time drawing than those who had not been rewarded.

On the basis of these results, Lepper et al. argued that there was a "hidden cost" to reward, which was that it undermined the children's intrinsic motivation. In their analysis, the children attributed their "drawing behavior" to the reward, rather than to their intrinsic desire to draw; and when the reward was removed, their desire to draw disappeared as well.

Note, however, that the results of the experiment are a little more complicated than that, because the children who received an unexpected reward did not show a decline in intrinsic motivation. If anything, they were more motivated to engage in the rewarded activity than they were before.

The Lepper study is often cited as an argument against the use of rewards as instruments of social policy. Lepper wrote a book describing his research entitled The Hidden Costs of Reward -- an argument that was repeated by Alfie Kohn in Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A's, Praise, and Other Bribes (1993). Nevertheless, a number of school districts and educational reform groups, as well as some private tutoring services, have proposed giving children money or other prizes as rewards for attending school and performing well. When, in 2007, the New York City Department of Education proposed rewarding students for school attendance and exam performance, in an attempt to improve educational outcomes for minority and other disadvantaged students, Barry Schwartz, a psychologist, cited Lepper's research in arguing against the plan (New York Times, 07/02/2007).

Nevertheless, such programs are increasingly popular. Of course, children around the world get their allowances contingent on cutting the grass or drying the dishes. But there's more: Schoolchildren are rewarded with cash and prizes for getting good grades, reading books, even just attending class and behaving properly; Homeowners are rewarded for recycling; Smokers are rewarded for cutting down or quitting; Employees are rewarded for skipping the french fries in the factory cafeteria; Adolescent girls are rewarded for not getting pregnant; Patients are rewarded for taking their medicine (examples from "The Age of Incentives: Paying Big Bucks for Puny Results" by Eric Felten,Wall Street Journal, 06/18/2010). Mainstream, market-based economists often favor proposals like these. But here are legitimate debates about the ethics of rewarding good behavior. And, as Lepper suggests, there are psychological reasons to think that they might backfire.

Enhancing Intrinsic Motivation

Actually, though, other research shows that rewards need not have deleterious effects on intrinsic motivation, and may even have positive effects. Recall that, even in the original Lepper study, an unexpected reward enhanced intrinsic motivation. A large body of subsequent research, much of it done by Judith Harackiewicz and her colleagues, has provided a much more detailed analysis of intrinsic motivation and the effects of reward.

In the first place, Harackiewicz argues that we have to consider the structure of reward.

Moreover, we have to consider the type of reward.

It turns out that these various aspects of reward make a big difference to the effects of rewarding behavior.

To illustrate, consider the case of Andre Agassi, one of the most accomplished tennis players of all time. Interestingly, Agassi confided in his 2009 autobiography,Open, that he actually hated playing tennis: he considered the sport to be like a prison that took his about 30 years to escape (see "Hate of the Game" by Sam Tanenhaus,New York Times Book Review, 11/22/2009). Agassi was introduced to tennis by his immigrant father, who was determined to raise a champion. His three elder brothers having failed at this task, the burden fell on Andre. Fortunately, he had some "natural" talent. As a preteen, he was sent from his home in Las Vegas to a tennis camp in Florida where he perfected his game but was allowed to do little else but play tennis (Agassi refers to it as "Lord of the Flies with forehands. And, as he made clear, he hated almost every minute of it. After the failure of his first marriage, to the actress Brooke shields, he married Steffi Graf, another major tennis star -- who, it turned out, hated the game as much as he did. They retired to Las Vegas, deliberately failing to equip their new home with a tennis court (so as not to create pressure on their children), and founded a charter school that focused on the cognitive and social development of disadvantaged youth. Agassi (and Graf) got all the rewards the world had to offer for their playing, rewards that should have been highly motivating, but their intrinsic interests lay elsewhere.

Here's another illustration, from the domain of public policy (discussed by Michael J. Sandel in What Money Can't Buy: The Moral Limits of Markets, 2012). In the 1990s, attempting to solve the problem of waste-storage from nuclear power generators, the Swiss government identified a small Alpine village as a possible waste-storage location. Prior to a referendum on the issue, the local residents were surveyed concerning their opinions on the issue. Of those residents who were asked if they would accept the repository in their area, 51% said yes. But another group was asked if they would accept the repository if the government provided each resident with a substantial amount of compensation. Interestingly, acceptance was cut in half, to about 25%. Prior to the survey, the residents thought that accepting the repository was a matter of civic duty. But they reacted negatively to the offer of compensation, believing that this was the sort of issue on which bribes were inappropriate.

In one early study, Harackiewicz (1979) varied the reward structure of the activity (junior-high-school pupils finding "Ninas" in cartoons by Abe Hirschfield; in the image to the right, there are 7 iterations of the name "Nina" embedded in the figure: click on the image to expand its size, and see if you can find them all!):

In this way, Harackiewicz was able to disentangle the informational aspect of rewards from the reward itself.  Later, in the free-choice situation, Harackiewicz found that reward, whether task-contingent or performance-contingent, did undermine intrinsic motivation, as in the Lepper study.  However, intrinsic motivation was enhanced by positive feedback concerning performance, regardless of whether the subjects were rewarded. Thus, reward does not always undermine intrinsic motivation. But the more important implication of this finding is that the effects of reward are very different, depending on how the are structured, the informatio they provide, and whether they are perceived as controlling.

It turns out that these various aspects of reward make a big difference to the effects of rewarding behavior. This was clearly demonstrated in a study of college students who were brought into the laboratory to do something that was intrinsically motivating for them -- playing pinball; as a reward, they received movie passes for achieving a meaningful but reasonable-sounding standard of performance (scoring above the 50th or 80th percentile); and rigging the machine to make sure that every one of the students met this standard. At the end of the experiment, all subjects were given an opportunity to continue playing the game during some free time, and the experimenters measured how long they continued playing.

(Let me just inject, as a point of personal privilege, that I keep in my head a "Faustian" list of experiments I would sell my soul to have done. It's a short list, and this one is on it. It's a real thing of beauty -- and I don't think that just because Harackiewicz was my very first graduate student!)

Then, the subjects were given an opportunity to continue playing the game during some free time.

In their first experiment, a promised reward undermined intrinsic motivation, compared to a standard control group that got performance feedback (i.e., they saw their score) but no evaluation and no reward. condition. But a third group that was surprised with the reward showed an enhancement of intrinsic motivation. This essentially replicates Lepper's original experiment, but with college students rather than nursery-school pupils. The promised reward could be perceived as controlling behavior, and probably was; and the subjects' anticipation of external evaluation probably induced performance anxiety. On the other hand, the unexpected reward was purely informational. The outcome suggests that controlling rewards undermine intrinsic motivation while purely informational rewards sustain, and may even enhance it.

In their second experiment, some subjects got the evaluation -- they were told that they had met the standard -- but received no reward . Again, this condition was intended to increase evaluation apprehension and performance anxiety, without the controlling element introduced by the offer of the movie tickets (the students got the movie tickets anyway, after they had completed their "free play" period). And again, this condition undermined intrinsic motivation, compared to the standard control group. But again, intrinsic motivation was enhanced for those students who were surprised with the purely informational unexpected reward (because there was no standard set or reward promised before, it was hoped that these subjects would not experience any evaluation apprehension or performance anxiety).

In a third experiment, again, some subjects got evaluative feedback but no reward offer; and, again, they showed diminished intrinsic motivation compared to the standard control group. Again, this illustrates the deleterious effects of evaluation apprehension and performance anxiety. But in this study the third group of subjects received information about normative performance -- they were told what the 80th percentile was -- but they got no promise of reward nor any hint of external evaluation (they did receive the reward, though, as a surprise). In this condition, they maintained or enhanced intrinsic motivation. So, if you can do it without seeming controlling, and without generating anxiety over performance evaluation, information about performance enhances intrinsic motivation, and giving a reward doesn't compromise it.

The upshot of this study is that rewards have at least two functions: they control performance, and they provide information about performance. Rewards that are perceived as controlling do undermine intrinsic motivation; but rewards that manage to provide information, without being perceived as controlling, do not undermine IM, and may even enhance it.

Based on these and other studies, Harackiewicz and Sansone (2000) have proposed a detailed process model of intrinsic motivation, discussing the various factors that can undermine, sustain, and even enhance intrinsic motivation.

All of these factors combine and interact to determine the level of a person's intrinsic motivation to engage in some activity.

Motivation and reward are not too important for learning, but they're obviously important for behavior. But extrinsic motives are not the sole determinants of behavior. Intrinsic motives are also important, and extrinsic motives do not always undermine intrinsic motives. The effects of reward on intrinsic motivation depend on what the reward is for, how the reward is perceived, and whether the person cares about the reward.

Interactions Between Motivation and Cognition

Kant argued that the three faculties of mind -- cognition, emotion, and motivation -- were independent of each other. On the other hand, some psychologists have argued that emotional and motivational states are dependent on cognition. In the lecture supplement on Emotion, we have seen how a number of theorists viewed emotions as products of cognitive appraisals. And it's also true that emotions can serve as "filters" on cognition -- as when we perceive the world "through rose-colored glasses".

The same points can be applied to motives -- although, frankly, there has been a lot less work on interactions between cognition and motivation, compared to those between cognition and emotion.

Cognitive Effects on Motivation

The Lepper study is a landmark in the cognitive-attributional interpretation of motivation. Just as Schachter and Singer (1962) did for emotion, the implication of the Lepper analysis is that motives are really merely beliefs about motivation -- beliefs that can be pushed around by situational manipulations. When no rewards are present, we believe that we want to do something. When rewards are present, we attribute the same behavior to the reward.

Motivational Effects on Cognition

On the other hand, it also appears to be true that motivation can affect cognition -- that what perception, memory, judgment, and decision-making can be influenced by our motivational states. To some extent, desire shapes thought.

Prospects for a Psychology of Human Motivation

There was a time when psychologists were strongly interested in motivation. Theorists such as Thorndike (in his Laws of Readiness and Law of Effect), and for Hull (in his formulation that E = HxD) but motivation -- drive and drive-reduction -- at the heart of their theories of learning, which in turn were at the heart of experimental psychology. Physiological psychologists sought to understand the roots of motives like hunger and thirst in the nervous system. Courses on motivation were once at the heart of the psychology curriculum.

Now, not so much. Interest in motivation was undermined by the radical behaviorism of John B. Watson and B.F. Skinner, who argued that psychology should confine itself to tracing the functional associations between environmental stimuli and organismal responses, without speculating about internal motivational states (or cognitive or emotional states either, for that matter). Skinner, for example, refused to define reinforcement in terms of the organism's needs or need satisfaction. For him, animals weren't hungry (an internal, "mental" state): they were simply food-deprived (a feature of the external environment). And a positive reinforcement wasn't something that made the animal feel good (or less hungry, or whatever). It was simply an environmental event that increased the probability of whatever behavior preceded it.

As with emotion, the cognitive revolution allowed psychologists to talk about motivation and other internal, mental states again -- even in nonhuman animals. There was, for example, a lot of talk about goals.But, as with emotion, cognition dominated psychological talk. To the extent that psychologists talked about motives at all, they tended to think of them, as in the Lepper experiment, as derived from cognition. We don't desire things, we just think we do.

But just as the cognitive revolution spurred an affective counterrevolution, so psychologists have started talking about motivation again. Post-McClelland research on achievement motivation (e.g., Dweck and her colleagues), and post-Lepper research on intrinsic motivation (e.g., Harackiewicz, Sansone, and their colleagues) have made these topics more popular than ever before. Moreover, research on human motivation has spilled over from psychology departments into schools of education and business.

This page last modified 04/03/2021.