Paper delivered at the Vienna Conference on Consciousness 2007 organized by the Faculty of Life Sciences at the University of Vienna, October 5, 2007.
Link to a précis of the talk, distributed in advance of the conference.
Link to general-interest article on "The Rediscovery of the Unconscious".
Link to other papers on the psychological unconscious.
Dammen und Herren, it is a privilege to speak to you today about the nature of unconscious mental life.
My graduate-school mentor, the late Martin T. Orne, was born in Vienna, and
both his parents, Frank Orne and Martha Brunner-Orne, were graduates of your
medical school, and among the founders of the Austro-American Association of
Boston.
My topic, of course, also has strong associations with the University of Vienna: Sigmund Freud, a graduate of this medical school, is commonly credited with the discovery of the unconscious mind. Of course, as Henri Ellenberger, the great historian of psychiatry, has shown, the psychological unconscious has a history long antedating Freud (Ellenberger, 1970). But even so, Ellenberger makes clear that the discovery of the unconscious was in a very real sense set in motion by yet another Vienna graduate of a century earlier: I speak of Franz Anton Mesmer, whose doctrine of animal magnetism evolved into hypnosis as we know it today. I happen to think that Mesmer does not deserve his currently poor reputation (Kihlstrom, 2002), but that is an issue for another time: my task today is to discuss the rediscovery of the unconscious mind by modern psychology.
Let me first make the terms of the discussion clear: We are talking about unconscious mental life. There are many physical and biological processes that, in some sense, proceed unconsciously: the expansion of the universe, the orbiting of planets around the sun, evolution by natural selection, photosynthesis, the machinations of DNA. The biochemistry of brain activity, which in humans at least gives rise to consciousness, itself goes on unconsciously. Considerations such as this led some Romantic philosophers, such as Edward von Hartmann, to declare that the unconscious pervades the universe. But as my colleague the philosopher John Searle has argued, the term unconscious only makes sense when applied to mental activity as a contrast to consciousness -- which leads us to ask what the hallmark of mental life is.
Here we turn to another son of Vienna, Franz Brentano (1838-1917), who
taught here from 1874 to 1895 – and who in fact taught Freud, and happily
included him in his "school". Brentano, of course, argued (in Psychology
from an Empirical Standpoint, 1874) that intentionality is the mark of
the mental: all mental states are intentional in nature, and only mental
states are intentional. Put another way, mental states are representational:
they are always about something. We don’t think, or feel, or desire in
the abstract; rather we think, feel, or desire something.
The nature of intentional states was further explicated by Bertrand Russell – another Vienna connection, if somewhat tangential, through Wittgenstein – in terms of propositional attitudes, which state a relation between a person and some proposition P. These attitudes come in various forms: namely, knowing, feeling, and wanting – Kant’s trilogy of mind (Hilgard, 1980), to which we can add believing. I know that Vienna is in Austria; I believe that Vienna is a beautiful city; I feel honored to have been invited here; and I want to deliver a convincing presentation.
Put in the standard language of cognitive psychology, these representations take the form of percepts, memories, knowledge acquired through learning, and thoughts. In an experiment, subjects perceive words that were presented on a computer screen; they remember words that appeared on a list; they learn a new fact about the world; or they think about some problem they encounter in their environment. Usually, these representations are accessible to consciousness, in that the subjects are aware of what is on their minds. The question for us is whether these same representations can exist outside the scope of phenomenal awareness, and nonetheless influence our ongoing experience, thought, and action.
It is important to frame the question in this way because in contemporary
psychology the most popular construal of unconscious mental life is in terms of automaticity
(Bargh & Ferguson, 2000). According to this view, some mental processes
occur outside the scope of conscious awareness and control. These processes are
inevitably evoked by the appearance of certain stimuli, are incorrigibly
executed once set in motion, consume little or no cognitive resources, and do
not interfere with conscious mental activities. Automatic processes are
unconscious in the strict sense that they are not available to phenomenal
awareness under any circumstances, and can be known only by inference. The
distinction between automatic and controlled processes is not without its
problems (Moors & DeHouwer, 2006), but has become widely accepted within
psychology, and lately a rather large industry has developed around its
application in social psychology (Kihlstrom, 2006).
But the fact that some mental processes can occur unconsciously says nothing
about whether the mental representations on which they operate, and which they
in turn generate, can be unconscious. Certainly automatic processes can act on
what Freud would have called preconscious representations, before focal
attention (cathexis) is directed to them. But the representations that they
generate are generally thought to be consciously accessible. I may not know how
unconscious inferences automatically generate the moon illusion (Kaufman &
Rock, 1962; Rock & Kaufman, 1962), but I am certainly aware of the moon when
I look at it, and I am aware that the moon looks larger on the horizon than it
does at zenith. So the question remains: can we have mental representations --
percepts, memories, thoughts, bits of knowledge – which are themselves
unconscious, yet influence our experience, thought, and action nonetheless?
Here the study of implicit memory represents a milestone in our
understanding of unconscious mental life. We now know that amnesic patients can
show priming effects, in which the presentation of a prime affects processing of
a target presented later, even though they cannot consciously remember the
prime. Priming effects exemplify what Daniel Schacter (Schacter, 1987) has
labeled implicit memory – or the influence of a past event on
subsequent experience, thought, or action, in the absence of conscious
recollection of that event.
Subsequent research has shown that explicit (conscious) and implicit
(unconscious) memory can be dissociated in a wide range of conditions, including
the amnesic syndrome associated with damage to the medial temporal lobes or
diencephalon, the anterograde and retrograde amnesias associated with
electroconvulsive therapy for depression, the anterograde amnesias produced by
both general anesthesia administered to surgical patients and conscious sedation
in outpatient surgery, dementia, including Alzheimer’s disease, normal aging,
posthypnotic amnesia, and the functional amnesias associated with dissociative
disorders such as fugue and multiple personality.
Here is a demonstration of the dissociation between explicit and implicit
memory in the amnesic syndrome: a profound impairment in free recall and
recognition, but spared priming on a fragment-completion task (Warrington &
Weiskrantz, 1970; see also Graf, Squire, & Mandler, 1984).
Just as implicit memory refers to the influence of past events that cannot
be consciously remembered, so implicit perception refers to the influence
of events in the current stimulus environment that cannot be consciously
perceived (Kihlstrom, Barnhardt, & Tataryn, 1992). Explicit and implicit
perception are dissociated in so-called subliminal perception, where priming
effects occur even though the prime is presented at an intensity, or for a
duration, that is below the threshold for conscious perception; or when the
prime has been masked by another stimulus.
Dissociations between explicit and implicit perception can also be observed
in other conditions, including blindsight associated with lesions to the striate
cortex (Weiskrantz, 1986), visual neglect resulting from damage to the temporo-parietal
area of the brain; prosopagnosia; hypnotic blindness and deafness; and the
"hysterical" blindness and deafness observed in cases of conversion
disorder. They have also been observed in "preattentive" processing in
such paradigms as parafoveal vision and dichotic listening, inattentional
blindness (Mack & Rock, 1998), repetition blindness, and the attentional
blink. In most of these cases the stimulus is in no sense subliminal, which is
why I prefer implicit perception as the more appropriate umbrella term.
Subliminal perception effects are sometimes classified as instances of implicit memory, on the ground that the presentation of the prime occurs before the presentation of the target. But in subliminal perception, the stimulus-onset asynchrony is extremely brief, less than a second, with no intervening distraction, so that the prime is presented in what William James called "the specious present". More important, in implicit memory the subject is aware of the prime when it is presented, but subsequently forgets it; in implicit perception the subject was never aware of the prime at all. On these grounds, priming by stimuli presented during general anesthesia are better counted as instances of implicit perception.
Here is a demonstration of the dissociation between explicit and implicit
perception in masked priming, with spared semantic priming in a lexical decision
paradigm in the absence of conscious perception (Marcel, 1983).
Apparently, subjects can also learn unconsciously, in the sense that new
knowledge acquired through experience can affect their ongoing behavior, without
being aware of what they have learned. So, for example, Arthur Reber (A.S. Reber,
1993) has shown that subjects can pick up on the "grammar" by which strings of
letters have been arranged, so that they can discriminate between
grammatical and ungrammatical letter strings, even though they cannot articulate
the grammar itself.
Similar implicit learning effects have been observed in a number of
different paradigms, including categorization, the detection of covariation,
sequence learning, and the control of complex systems. Again, these effects are
sometimes classified as instances of implicit memory, but source amnesia, where
subjects are aware of what they know but cannot remember where they have learned
it, is a better example of implicit memory. By contrast, subjects in implicit
learning remember their learning experiences quite well – they just aren’t
consciously aware of what they have learned from them. I prefer to reserve that
term for unconscious episodic memory – memory for events embedded in a
specific spatiotemporal context. Thus, implicit learning refers to the
acquisition of semantic or procedural knowledge.
Here is a demonstration of the dissociation between explicit and implicit
learning in neurologically intact subjects: having memorized a set of letter
strings generated by a finite-state grammar, subjects are able to discriminate
among grammatical and ungrammatical letter strings, despite being unable to
identify the grammatical rules themselves (A. S. Reber, 1989).
There is even some evidence of implicit thought – where subjects
are influenced by ideas that are not, themselves, properly construed as percepts
or memories (Dorfman, Shames, & Kihlstrom, 1996; Kihlstrom, Shames, &
Dorfman, 1996).
For example, the late Kenneth Bowers and his colleagues (Bowers, Regehr,
Balthazard, & Parker, 1990) showed that subjects could discriminate between
problems that were soluble and those that are not, even though they had not
actually arrived at the solutions in question.
Similar effects have been observed in both neurological patients and intact
subjects making risky choices, and in studies of insight learning.
Bowers concluded that an unconscious representation of the solution
influenced subjects’ choice behavior, and I think there is merit in his
further suggestion that such "intimations" are related to the
intuition phase of creative problem-solving. In this view, the unconscious
solution gathers strength during the incubation phase, and emerges fully into
consciousness as an insight.
In addition to this evidence for the cognitive unconscious, there are also hints of unconscious emotion and motivation.
David McClelland and his colleagues, for example, claimed that procedures
such as the Thematic Apperception Test assessed subjects’ unconscious motives,
while personality questionnaires such as Jackson’s Personality Research Form
assessed conscious motives (McClelland, Koestner, & Weinberger, 1989).
Viewed
from this perspective, the frequently lamented lack of substantial
correlation between "projective" and "objective" assessments
of motive dispositions counts as a dissociation between explicit and implicit
motivation (e.g., Spangler, 1992).
In addition, there is some evidence that explicit and implicit motives are
elicited by different kinds of stimuli, and predict performance on different
types of tasks.
On the affective side of the ledger, Peter Lang cogently argued that, in
principle, every emotional state consists in three components: the subjective
feeling, the physiological correlate, and the behavioral response.
If so, then -- at least in principle – we can identify explicit emotion
with the subjective feeling state, and implicit emotion with the
behavioral and physiological components. Where physiological or behavioral components of emotion occur in the absence
of a feeling state, I think we can rightly speak of a dissociation between
explicit and implicit emotion (Kihlstrom, Mulvaney, Tobias, & Tobis, 2000).
Lately, social psychologists such as Anthony Greenwald, Mahzarin Banaji, and
their colleagues have introduced the Implicit Association Test, a reaction-time
measure intended to reveal prejudices and other attitudes that subjects are not
aware of harboring (Greenwald et al., 2002).
But I think the first experimental evidence for the kind of dissociation I
have in mind was provided by Winkielman and his colleagues, who presented
"subliminal" (actually masked) pictures of smiling and frowning faces
to subjects, in an attempt to prime positive or negative moods (Winkielman,
Berridge, & Wilbarger, 2005). In fact,
the subjects' mood-ratings showed no difference between the two
conditions. Nevertheless, the subjects primed with the happy faces drank
more of a beverage, and increased their desire and willingness to pay for that
beverage, compared to those primed with the sad faces. Given that mood is
related to consummatory behavior, we can say that the subjects showed behavioral
expressions of positive emotion, even though they were unaware of any change in
their feeling state.
Although these kinds of findings give sufficient reason for taking
unconscious mental life seriously, it has to be said that the evidence in each
of these domains is not equally strong. I think that implicit perception and
memory have now been established to the satisfaction of all but a few critics
(and I think that nothing would convince these dissenters anyway!). Implicit
thought is on somewhat softer ground, if only because there have been so few
relevant studies. Implicit learning has been explored in the laboratory for more
than 40 years, but I think that the dissociation between explicit and implicit
learning has not been established with the rigor that characterizes research in
the domains of perception and memory.
This holds true for implicit motives, and implicit emotions, as well. For
example, the correlations between explicit attitudes measured by rating scales
and implicit attitudes measured by the IAT are often quite substantial (at least
by the standards of personality research), suggesting that the IAT is more an
unobtrusive measure of conscious attitudes that subjects would rather not
reveal, than a measure of unconscious attitudes as such.
There is also the matter of the comparative power of unconscious processing.
Recently, in both the scientific literature and the popular press, authors have
touted the power of unconscious learning and thought – that unconscious
learning and automatic processing allow us to solve more complex problems, more
efficiently, than is possible consciously (Gladwell, 2005; Wilson, 2002).
In some sense, these claims revive Romantic notions of the power of The
Unconscious that were popular in the 19th century (Hartmann,
1868/1931). But it has to be said that these claims are not well founded in the
scientific evidence – if for no other reason than that there are relatively
few methodologically adequate comparisons of conscious and unconscious
processing. There is every reason to think that unconscious perception is
analytically limited, for example. Universities like this one, where an older generation
teaches what it knows to a younger one, are ample evidence of the power and
importance of conscious, deliberate thinking, and conscious, deliberate
learning.
More to the point, the debate over automaticity testifies to the odd situation that consciousness still makes psychologists uncomfortable – the
philosopher Own Flanagan calls it conscious shyness (Flanagan, 1992).
Partly as a holdover from the bad old days of behaviorism, and partly as a
reflection of the functionalist stance that is so popular in the philosophy of
mind, psychologists and other cognitive scientists are often reluctant to take
consciousness seriously, or even utter the word. Still, we must take care that
our acceptance of unconscious mental life does not tilt unnecessarily into a
stance of conscious inessentialism or epiphenomenalism.
Beyond mere acceptance that the psychological unconscious is a viable
concept after all, the phenomena I’ve described here may offer a new approach
to one of the central problems in psychology, cognitive science, and
neuroscience – what, following Wittgenstein (there’s that Vienna connection
again) we might characterize as the puzzling leap from body to mind: what are
the neural substrates of conscious awareness?
We get part of the answer from studies of sleep and dreams, like Prof.
Hobson’s (Hobson, Pace-Schott, & Stickgold, 2000), and from studies of
general anesthesia. But we will also get part of the answer from comparing the
neural correlates of explicit and implicit perception, memory, thought, and the
like. The explicit-implicit distinction offers a natural control condition for
neuroscientific research: what are the differences, in terms of neural activity,
between the conscious and the unconscious influence of percepts and memories. In
this way, we may get new insights into precisely what makes conscious percepts,
and conscious memories, conscious.
Among these insights, I think, is that the neural correlates of consciousness are going to be as variable as consciousness itself. Conscious recollection has its seat in the hippocampus and the rest of the medial temporal lobe memory system, but conscious (visual) perception has its seat in the striate cortex. Where the neural correlates of consciousness lie may depend precisely on what people are conscious of.
Setting neuroscience aside, the explicit-implicit distinction also gives us
some insight into the psychological distinction between conscious and
unconscious mental life. Returning to Brentano’s and Russell’s discussion of
intentionality, note that each of their examples of a mental state invoke the
self, and delineate a kind of ownership between the person and what is going
through his or her mind. In linguistic terms, conscious mental states always
include some reference to the self as the agent or patient of some action, or
the stimulus or experiencer of some state.
Consider the sorts of tasks in which we demonstrate the dissociation between
explicit and implicit memory (e.g., Graf, Squire, & Mandler, 1984). First,
the subject studies a list of words, including the word paragon. On an
explicit memory task, the subject is asked what he or she remembers, and
replies, in effect, "I remember" such-and-such an event from the past
-- with the emphasis on the first person: "I remember studying this
item". But when a subject is asked to complete a word-stem or a
fragment, or to identify a word, or to determine whether a letter string is a
word, self-reference is missing, or is there in a very different way: "That
fragment can be completed with paragon", instead of the more
familiar response parachute, or parallel. Whatever is going on in
the brain during conscious perception and memory, what is going through the mind
is a connection between some mental representation of some object or event, and
a mental representation of the self. This link is, I think, missing in instances
of unconscious processing (Kihlstrom, 1997).
More than 200 years ago, Immanuel Kant asked whether the notion of
unconscious mental states made any sense, and concluded that it does.
But only 100 years ago, writing during the infancy of psychology, William
James warned in
the Principles that the unconscious was "the sovereign means
for believing what one likes in psychology, and of turning what might become a
science into a tumbling-ground for whimsies". It is all too easy for us, as
psychologists, especially psychologists still living in the shadow of Freud, to
tell people what they unconsciously believe, or feel, or want – how
could they possibly contradict us? Studies of automatic and controlled
processes, and of explicit and implicit perception, memory, and the like, offer
a solution to James’ warning, because they offer strict criteria for
identifying unconscious mental processes and unconscious mental states – and
for tying inferences about subjects’ unconscious mental lives to objective
evidence of their behavior in the controlled environment circumstances of the
laboratory.
The result is that we can now talk about the unconscious in a scientifically
respectable way, and discover its scope and limitations, and seek to identify
the neural correlates of consciousness.
That, I think, is a great advance in the science of mental life, and I thank you for the opportunity to share it with you.
Bargh, J. A., & Ferguson, M. J. (2000). Beyond behaviorism: On the automaticity of higher mental processes. PSYCHOLOGICAL BULLETIN, 126(6 Sp Iss), 925-945.
Bowers, K. S., Regehr, G., Balthazard, C., & Parker, K. (1990). Intuition in the context of discovery. Cognitive Psychology, 22, 72-110.
Dorfman, J., Shames, V. A., & Kihlstrom, J. F. (1996). Intuition, incubation, and insight: Implicit cognition in problem solving. In G. Underwood (Ed.), Implicit cognition. (pp. 257-296). Oxford, England UK: Oxford University Press.
Ellenberger, H. F. (1970). The discovery of the unconscious: The history and evolution of dynamic psychiatry. New York: Basic Books.
Flanagan, O. (1992). Consciousness reconsidered. Cambridge, Ma.: MIT Press.
Gladwell, M. (2005). Blink: The power of thinking without thinking. Boston: Little, Brown.
Graf, P., Squire, L. R., & Mandler, G. (1984). The information that amnesic patients do not forget. Journal of Experimental Psychology: Learning, Memory, and Cognition, 10, 164-178.
Greenwald, A. G., Banaji, M. R., Rudman, L. A., Farnham, S. D., Nosek, B. A., & Mellott, D. S. (2002). A unified theory of implicit attitudes, stereotypes, self-esteem, and self-concept. Psychological Review, 109(1), 3-25.
Hartmann, E. v. (1868/1931). Philosophy of the unconscious: Speculative results according to the inductive method of physical science. London: Routledge and Kegan Paul.
Hilgard, E. R. (1980). The trilogy of mind: Cognition, affection, and conation. Journal for the History of the Behavioral Sciences, 16, 107-117.
Hobson, J. A., Pace-Schott, E., & Stickgold, R. (2000). Dreaming and the brain: Towards a cognitive neuroscience of conscious states. Behavioral & Brain Sciences, 23(6).
Kaufman, L., & Rock, I. (1962). The moon illusion: I. Science, 136, 953-961.
Kihlstrom, J. F. (1997). Consciousness and me-ness. In J. D. Cohen & J. W. Schooler (Eds.), Scientific approaches to consciousness (pp. 451-468). Mahwah, N.J.: Erlbaum.
Kihlstrom, J. F. (2002). Mesmer, the Franklin Commission, and hypnosis: A counterfactual essay. International Journal of Clinical & Experimental Hypnosis, 50, 408-419.
Kihlstrom, J. F. (2006). The automaticity juggernaut. In J. Baer, J. C. Kaufman & R. F. Baumeister (Eds.), Psychology and free will (pp. in press). New York: Oxford University Press.
Kihlstrom, J. F., Barnhardt, T. M., & Tataryn, D. J. (1992). Implicit perception. In R. F. Bornstein & T. S. Pittman (Eds.), Perception without awareness: Cognitive, clinical, and social perspectives. (pp. 17-54). New York, NY, USA: The Guilford Press.
Kihlstrom, J. F., Mulvaney, S., Tobias, B. A., & Tobis, I. P. (2000). The emotional unconscious. In E. Eich, J. F. Kihlstrom, G. H. Bower, J. P. Forgas & P. M. Niedenthal (Eds.), Cognition and emotion (pp. 30-86). New York: Oxford University Press.
Kihlstrom, J. F., Shames, V. A., & Dorfman, J. (1996). Intimations of memory and thought. In L. M. Reder (Ed.), Implicit memory and metacognition (pp. 1-23). Mahwah, N.J.: Erlbaum.
Mack, A., & Rock, I. (1998). Inattentional blindness. Cambridge, Mass.: MIT Press.
Marcel, A. J. (1983). Conscious and unconscious perception: An approach to the relations between phenomenal experience and perceptual processes. Cognitive Psychology, 15, 238-300.
McClelland, D. C., Koestner, R., & Weinberger, J. (1989). How do self-attributed and implicit motives differ? Psychological Review, 96, 690-702.
Moors, A., & DeHouwer, J. (2006). Automaticity: A Theoretical and Conceptual Analysis. Psychological Bulletin, 132(2), 297-326.
Reber, A. S. (1989). Implicit learning and tacit knowledge. Journal of Experimental Psychology: General, 118, 219-235.
Reber, A. S. (1993). Implicit learning and tacit knowledge: An essay on the cognitive unconscious. Oxford, U.K.: Oxford University Press.
Rock, I., & Kaufman, L. (1962). The moon illusion: II. Science, 136, 1023-1031.
Schacter, D. L. (1987). Implicit memory: History and current status. Journal of Experimental Psychology: Learning, Memory, and Cognition, 13, 501-518.
Spangler, W. D. (1992). Validity of questionnaire and TAT measures of need for achievement: Two meta-analyses. Psychological Bulletin, 112, 140-154.
Warrington, E. K., & Weiskrantz, L. (1970). Amnesia: Consolidation or retrieval? Nature, 228, 628-630.
Weiskrantz, L. (1986). Blindsight: A case study and implications. Oxford, U.K.: Oxford University Press.
Wilson, T. D. (2002). Strangers to Ourselves: Discovering the Adaptive Unconscious. Cambridge, Ma.: Belknap Press of Harvard University Press.
Winkielman, P., Berridge, K.C., & Wilbarger, J.L. (2005). Unconscious affective reactions to masked happy versus angry faces influence consumption behavior and judgments of value. Personality & Social Psychology Bulletin, 31, 121-135.
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