Home Introduction Prescientific 19th Century Interference Cognitive Primary Learning Representation Encoding Storage Retrieval Implicit Memory Implicit Learning Neural Bases Modeling Development Emotion Personal Social Conclusion


This is a course about learning and memory -- but mostly, frankly, about memory.  The two topics are, obviously, closely related.  Learning could not take place without the capacity to retain what has been learned.  And nothing gets retained in memory unless it has been learned.  


The traditional definition of learning is as

 a relatively permanent change in behavior which results from experience.

This definition rules out innate responses to stimulation, such as:

It also rules out more permanent behavioral changes caused by other processes:

From a cognitive point of view, however, learning is better defined as 

a relatively permanent change in knowledge that results from experience.

The canonical cases of learning are the classical conditioning discovered by the Russian physiologist I.P. Pavlov (who got the Nobel Prize for his trouble), and the instrumental conditioning discovered by the American psychologist E.L. Thorndike -- both in 1898.  (The terms themselves were popularized, if not coined, by Hilgard and Marquis (1940).

But there are also special cases of learning.
There are examples of observational learning in nonhuman species -- most prominently, in Mineka's classic experiments on the observational learning of fear in rhesus monkeys.  According to the cognitive social learning theory promoted by Bandura and others, observational learning may have special rules.
No matter what kind of learning is involved, whatever has been learned obviously has to be stored somewhere, so that it can be used later as appropriate.  Without a capacity for memory, organisms would have no ability to permanently change behavior as a result of experience.  



Given the cognitive definition of learning as a change in knowledge resulting from experience, as a first approximation we may define memory as the mental repository of stored knowledge, acquired through experience -- including knowledge of the learning experience itself.

The concept of memory could be expanded to include innate knowledge, which is a product of the organism's evolutionary and genetic heritage.  But we have to draw a line somewhere -- and we want to draw it before we get to reflexes, taxes, and instincts.  Thus, in this course, we will limit memory to mental representations of knowledge acquired through experience.

Even so, it's clear that the contents of memory can range widely.  Memory can take many different forms, corresponding to the many different forms that knowledge can take.

Slide8.JPG (46010
              bytes)One hierarchical classification of memory begins with the distinction between two forms of knowledge -- a distinction with origins in computer science  (Winograd, 1975) that was imported into psychology (Anderson, 1976):

The knowledge acquired through classical and instrumental conditioning can be thought of as procedural in nature:

Of course, no individual piece of knowledge stands in isolation.  Each item in memory is linked to many others.  

AssNet.JPG (45499
              bytes)In declarative memory, there is an associative network where nodes represent concepts, and associative links represent the relations between them.


ProdSys.JPG (95303
              bytes)In procedural memory, there is a production system in which the output of each individual production serves as input to some other production.



And, for that matter, declarative and procedural memory are also related:

In the hierarchical classification of memory, procedural knowledge can be subdivided into two categories:

Following Tulving (1983), we can subdivide declarative memory into two categories:

AutoMem.JPG (58352
              bytes)Episodic memory concerns factual knowledge about discrete events -- episodes in an organism's experience -- with each event tied to a unique spatiotemporal context (two events can't occur at the same time in the same place).  Episodic memory is, in a sense, autobiographical memory, because it concerns the behaviors and experiences of an individual organism (though, as we will see, autobiographical memory is more than a record of discrete episodes).


Semantic memory concerns more abstract, generic, context-free knowledge.  Semantic memory constitutes a sort of "mental dictionary" or encyclopedia of world-knowledge.

Like learning and memory, episodic and semantic memory are related.

In this course, we are primarily concerned with episodic memory, but we will also have things to say about semantic and procedural memory.  


Mind and Brain

Levels.JPG (32988
              bytes)Memory is a mental capacity, and episodic memories are mental representations of past events, and this course will be primarily concerned with the psychological analysis of memory as an aspect of mental life.  But the brain is the physical basis of mind: whatever is represented in memory also has to be represented in the brain.  Accordingly, this course will also discuss the anatomy and physiology of learning and memory -- what physiological changes underlie the changes in behavior that take place as a result of experience; and the neural representation of knowledge and experience.

Some comments are in order concerning the relationship between cognitive psychology and cognitive neuroscience. Neuroscience is a very useful tool for psychology, because it connects psychology to the other biological sciences.  Some neuroscientists make the strong claim that neuroscientific knowledge will constrain psychological theory.  While I would quarrel with that position, because psychology is a biological science (as well as a behavioral science, a cognitive science, and a social science!), the relations between the mental and the physical is an enduring question for psychology.  

But, as someone (not me) once said, physiology is a tool for psychology, not an obligation.  A scientific analysis of memory can proceed exclusively at the psychological level -- deriving the principles of how knowledge is represented, and how memories are processes.  From this point of view, the biological basis of learning and memory is an interesting question, but it is not the focus of psychology.

In any event, advances in knowledge at the biological level of analysis depend on knowledge at the psychological level.  Psychological theory tells neuroscientists what to look for in the brain, and shows them how to interpret brain activity.  Put crudely: you can put subjects in a brain-imaging machine and give them something to learn, and some part of the brain will surely light up.  But without a clear understanding of the task at the psychological level of analysis, we would have no idea what that part of the brain is doing.  We would be left only with a kind of sophisticated phrenology.

Stage Analysis of Memory

Memory can be thought of as the mental storehouse of knowledge, but it is also an activity.  when knowledge is acquired through learning, retained over time, and used in performance, memories are being processed.  

In cognitive psychology, we analyze the processing of episodic memories in terms of three stages:

Note that, in principle, successful remembering requires success at all three stages:

Therefore, any particular instance of forgetting can involve a failure at any of these stages, alone or in combination.

Stage analysis is reflected in the library metaphor of memory, in which a memory trace is analogous to a book:

The encoding stage is where learning takes place.  Everything depends on this acquisition stage: no learning, no memory.  

This emphasis on encoding illustrates the intimate relationship between memory and perception: No perception, no memory.  Every experience changes the contents of memory.  

Following Richard Semon and Karl Lashley, we can define the engram as the lasting trace of experienced objects and events, which persists in memory after the experience is over.  According to the encoding specificity principle, to be discussed later, what can be retrieved depends on what has been encoded -- how an event has been processed at the time of perception.

Of course, perception also depends on memory.  Jerome Bruner famously observed that every act of perception is an act of categorization.  Perception is not complete until the stimulus event has been identified and categorized.  In this process, the perceptual representation makes contact with pre-existing knowledge stored in memory.  

In the final analysis, perception combines information from two sources:

Beyond the Library Metaphor

But the library metaphor makes clear that memory is not just a matter of encoding; it's also a matter of retrieval.  Stored memories are of no use unless one can gain access to them.  Tulving and Pearlstone (1966) made an important distinction between the availability of a memory in storage and the accessibility of that memory at the time retrieval is attempted.  Knowledge is made available by encoding and storage processes, but we gain access to available knowledge through retrieval processes.  And retrieval is not simply automatic.

The library is a powerful metaphor for memory, but it is also misleading. F.C. Bartlett (1932) had the insight that both perception and memory entailed effort after meaning: in perceiving, and remembering, we try to make sense of what we perceive and remember.  

Put another way, both perceiving and remembering represent problem-solving activity.

So, just as perception is constructive in nature, so memory is reconstructive in nature.  Both cognitive activities rely heavily on judgment and inference.

From Bartlett's point of view, then, we recreate events and experiences each time we remember them.  Beginning with fragmentary details stored in the memory trace, and suggested by other information available at the time of retrieval (including information contained in the query itself), we then engage in reconstructive activity, filling in gaps and fleshing out details, making inferences from our world-knowledge about what might have happened.

The point of Bartlett's analysis is that remembering is not so much like reading a book -- it's more like writing a book anew from fragmentary notes.

Thus, memory is linked not just to perception, but also to other cognitive processes of reasoning, judgment, inference, problem-solving, and decision-making.  Because memory depends on both perception and reasoning, it stands at the very center of cognitive psychology.


This page last modified 05/27/2014.