Conclusion

Learning and memory can be studied from a variety of vantage points.

First, memory is a critical psychological function. You can have a behaving organism which doesn't have a memory -- which operates purely on reflex, taxis, and instinct to respond to physical stimuli that are present in the current environment.  But such an organism is severely limited. 

• It can't respond to situations that are not physically present, because it has no way of representing them mentally.
• It can't respond to a rapidly changing environment, because its behavioral mechanisms have been fixed over the slow course of evolutionary time.
• It can't analyze current stimuli for meaning, because it lacks the cognitive capacity to analyze anything beyond the physical stimulus.

Memory takes us beyond the present, and permits us to transcend the here-and-now.  Without memory, intelligent behavior -- behavior which responds flexibly to changes in the situation --  just isn't possible, because memory provides the cognitive basis for other cognitive functions.

In particular, memory affords the possibility of learning, defined traditionally as relatively permanent changes in behavior that occur as a result of experience -- because memory is what makes these changes permanent. Without memory, some capacity to store the changes in knowledge that underlie the changes in behavior, learning just isn't possible.

Memory is also the cognitive basis of perception.  In Bruner's famous aphorism, perception requires that the perceiver go "beyond the information given" by the proximal stimulus. 

• Memory allows the perceiver to recognize a distal stimulus as familiar, by connecting the current event to past events.
• Memory allows the perceiver to infer the attributes, correlates, and consequences of the stimulus, by drawing on previously acquired world knowledge.
• Put another way, paraphrasing Bruner, every act of perception is an act of categorization.  In categorization, the mental representation of the stimulus makes contact with pre-existing knowledge stored in memory, so that the perceiver can determine how the stimulus is similar to some objects and events, and different from others.  This categorical knowledge is stored in memory, and categorization changes the contents of memory -- by adding a new instance to the category.

• The rules of judgment, decision-making, and grammar are stored in memory.
• Objects and events are symbolically represented by words, and this mental lexicon is also stored in memory.

• Some emotional responses involve the comparison between the present and the past.  This is not possible without mental representations of the past stored in memory.
• Some motives involve representations of long-term goals, not immediately presented by the environment.  This, also, is not possible without mental representations of the future stored in, or at least generated by, memory.

These considerations show us what kind of memory an intelligent organism has to have.  Memory must be capable of storing mental representations of knowledge acquired through experience.

• Semantic memory a component of declarative memory, which stores the meanings of words and other symbols, and the definitions of categories.
• Procedural memory, storing the repository of skills, rules, and strategies used to manipulate and transform symbolic representations, and translate ideas into actions.

All behaving organisms must have this sort of memory, and the more of it they have, the more intelligent their behavior will be.  This is because memory permits them to alter their behavior in response to changing circumstances, and to manipulate symbols instead of responding to stimuli.

But human behavior stores more than generic knowledge of symbols and rules.  It also stores mental representations of particular experiences, or episodic memory. 

• Episodic memory  stores knowledge of particular experiences -- knowledge which makes reference to a specific episodic context, the time and place in which an event occurred.
• Episodic memory also records the involvement of the self as the agent or patient of some action, or the stimulus or experiencer of some state.

• Memory stores mental representations of knowledge acquired through experience.
• Memory honors a distinction between declarative and procedural knowledge, or between facts and rules.
• And there are two forms of declarative knowledge, episodic and semantic, or between abstract and contextualized facts.

For the most part, the scientific study of learning involves the acquisition of abstract knowledge -- how we learn things in general: the meanings of words, the attributes of concepts, and cognitive skills.  This work began with Pavlov and Thorndike, and links human learning with animal learning.

For the most part, the scientific study of memory involves the acquisition of episodic memory -- how we construct and maintain an autobiographical narrative, and how we consciously recollect our own, unique, personal experiences.  This work began with Ebbinghaus, and has yielded a small but comprehensive set of principles governing encoding, storage, and retrieval which effectively summarize what we know about how memory works:

• Elaboration
• Organization
• Time-Dependency
• Consolidation
• Interference
• Availability vs. Accessibility
• Cue-Dependency
• Encoding Specificity
• Transfer-Appropriate Processing
• Schematic Processing
• Reconstruction
  

But we've also learned that episodic memory goes beyond conscious recollection, and includes implicit as well as explicit memories -- that is, representations of past experiences that influence experience, thought, and action in the absence of conscious recollection. 

• In some respects, implicit memories appear to alter the rules of memory, because they appear to be less dependent on elaborative processing at the time of encoding.
• The distinction between implicit and explicit memories is very important, because it shows that the hoary notion of unconscious influence is scientifically viable, and provides us with a methodology for studying unconscious influences in other domains. 
  
• It also raises the question of how conscious and unconscious memories differ, and may lead to a better understanding of consciousness itself.

Memory and the Brain

• We always understood that the nervous system had something to do with it(!).  Mental representations of knowledge and experience must have corresponding representations at the neural level.
• Now, newly emerging technologies such as brain-imaging and single-unit recording permit us to go beyond earlier studies involving brain lesions and surface recordings such as the EEG.
• The biological basis of memory can be approached at many different levels of biological structure:
• Cell
• Tissue
• Organ
• System

• The repeated joint firing of particular pre- and post-synaptic neurons increases the strength of the synaptic connection between them.
• The result is a reorganization of neural tissue as a result of experience -- a reorganization that constitutes the neural substrate of learning.

• The medial temporal lobe memory system consists of the hippocampus and related structures, such as the perirhinal cortex, entorhinal cortex, and parahippocampal cortex.
• This appears to be critical for the conscious recollection of past experiences.
• It is not critical for the acquisition of procedural or semantic memories.
• It is not critical for the implicit expression of episodic memories.
• There are probably other brain systems which mediate other aspects of learning and memory.
• The amygdala may play a special role in emotional learning.
• The cerebellum seems to play a critical role in classical conditioning.
• The cerebellum -- it's not just for motor coordination any more.

• What accounts for the experience of "reliving" a past episode.
• The nature of unconscious memories of the past.

• Episodic memory, especially, is critical to the personal self: it's the narrative record of autobiographical memory, and reflects how the individual organizes and understands his own experiences and actions.
• So we need to understand the individual's memory, as an aspect, and expression, of identity -- how what a person remembers relates to who that person is.
• And we need to understand how memory relates to other aspects of personality, particularly the person's affective and conative life.
• Just as memories are reconstructed, not just retrieved, so personality is continually shaped and reshaped by experience.
• We can study memory to understand these formative experiences.
• But memory may also be reciprocally shaped by personality.
• What a person is may determine what s/he will remember.

In either case, we need to understand the relation between one's personal recollections and one's theories about oneself.

Memory in Social Relations

In analyzing individual aspects of memory, we must take account of sociocultural factors.  Individuals don't live in isolation from each other.  Rather, we live in groups based on cooperation, competition, and social exchange.  Therefore, we can't understand the individual's mental life and behavior without taking into account the sociocultural context in which the individual lives his/her life.  For this reason, we can't just analyze memory as an individual mental faculty or biological function. 

• At the very least, we need to understand how the individual's memories may be shaped by social influences.  The same processes of conformity and persuasion that shape the individual's beliefs, attitudes, and behaviors may shape the individual's memories of the past as well.
  
• Also, sharing of memories is an important social function.
• Flashbulb memories connect individual's personal narratives to the historical record.
• Shared memories connect individual people to each other.

Moreover, societies and cultures have memories too, and these social representations of the past transcend individual recollections.

• Consider the ethnic conflict in the former Yugoslavia, where the rallying cry of the Serbs against the Muslims was, essentially, "Remember 1389".
• But nobody remembers 1389 -- at least, not as a personal recollection.
• Still Serb cultural identity depends on the preservation of this memory.
• Similarly, consider the motto of survivors of the Holocaust during World War II: "Never forget".
• But within the next half-century, the last Holocaust survivor will be dead.
• Still, memories of the Holocaust will persevere in cultural artifacts such as Yad Vashem in Israel, and Holocaust memorials in many other countries around the world.

What is the nature of collective memory?

• Societies preserve representations of the past in the form of memorials, monuments, and museums such as the Pearl Harbor Memorial and Veterans Day.
• Cultures also preserve representations of the past.
• In Christianity, the festival of Christmas commemorates the birth of Jesus.
• In Hispanic cultures, La Posada re-enacts the search of Mary and Joseph for shelter in Jerusalem.
• In Judaism, Hanukkah celebrates the victory of the Jews over Syria, and the re-dedication of the Temple.
• In Islam, Ramadan celebrates the revelation of the Koran to Mohamed.
• The evolutionary biologist Richard Dawkins has introduced the concept of memes to refer to elements of culture which are preserved in knowledge, belief, and memory.
• Naturally, for an evolutionary biologist, Dawkins believes that memes are preserved, and modified, through a process analogous to natural selection.
  

Just as we need to know about memory as an individual mental function, we also need to know about collective memory as a sociocultural construct.

We also need to know about the relations between individual and collective memory.

A major plot device in George Orwell's novel, 1984, was the memory hole, which was an instrument for destroying documents, rather than preserving them, as the official version of history changed -- and the representation of the past must be changed accordingly.  Big Brother's assumption, apparently, is that individual memory is also malleable, and that personal recollections will fall in line with the official story.  But this isn't necessarily the case, raising the question of whether individual memories can resist collective forces.

A full analysis of individual and collective memory is that memory is not just a subject for cognitive psychologists, and cognitive neuroscientists, anymore.  A complete understanding of the nature and function of memory requires contributions from other fields.

• Personality, social, and clinical psychology.
• Sociology, anthropology, and history
• Literary studies, and even music and art history.