MEMORY

2nd Edition

Chapter 5

Interactive exercise

Quiz

Glossary

Amygdala:
An area of the brain close to the hippocampus that is involved in emotional processing.
Cell assembly:
A concept proposed by Hebb to account for the physiological basis of long-term learning, which is assumed to involve the establishment of links between the cells forming the assembly.
Change blindness:
The failure to detect that a visual object has moved, changed, or been replaced by another object.
Consolidation:
The time-dependent process by which a new trace is gradually woven into the fabric of memory and by which its components and their interconnections are cemented together.
Consolidation of memory:
A process whereby the memory becomes more firmly established. It is commonly now divided into two processes, synaptic consolidation a process that is assumed to involve the hippocampus and operate over a 24 hour timescale, and systems consolidation. This is assumed to operate over a much longer period, and to involve the transfer of information from the hippocampus to other parts of the neocortex.
Distributed practice:
Breaking practice up into a number of shorter sessions; in contrast to massed practice, which comprises fewer, long, learning sessions.
Expanding retrieval:
A learning schedule whereby items are initially tested after a short delay, with pretest delay gradually increasing across subsequent trials.
Fragment completion:
A technique whereby memory for a word is tested by deleting alternate letters and asking participants to produce the word.
Hippocampus:
Brain structure in the medial temporal lobe that is important for long-term memory formation.
Immersion method:
A strategy for foreign language teaching whereby the learner is placed in an environment where only the foreign language is used.
Latent inhibition:
Classical conditioning phenomenon whereby multiple prior presentations of a neutral stimulus will interfere with its involvement in subsequent conditioning.
Mere exposure effect:
A tendency for a neutral stimulus to acquire positive value with repeated exposure.
Nonsense syllable:
Pronounceable but meaningless consonant-vowel-consonant items designed to study learning without the complicating factor of meaning.
Stem completion:
A task whereby retention of a word is tested by presenting the first few letters.
Total time hypothesis:
The proposal that amount learned is a simple function of the amount of time spent on the learning task.

Flashcards

Research activity: learning strategies

Think carefully about how you go about revising for an exam or test. Imagine you were trying to revise for an exam that would test the contents of this chapter on learning; how would you go about it?

Very few of us are lucky enough to have a photographic memory, so there is no point simply reading and hoping that we can learn the content verbatim. First we have to cut the information down into suitable “learnable” elements or “chunks” of information and only then can we realistically start to try to learn it.

There are a number of strategies that we know can help us to learn; one of them is through “expanding retrieval” (see p.112 of Memory, 2nd edition). This is where you receive feedback from your learning at greater and greater intervals from the actual learning. As the information is better learned the practice–test interval is gradually extended. Another important aspect of this process is the way that the information is represented. Many of us don’t work very well from lists, and so some people try representing the information they wish to learn within some kind of “mind map.” This is where the information is represented within a semi-graphical format. Try using a blank piece of paper. Write “Learning” in the center; now put a circle around it. Then, within other circles around the center write down some of the main learning topic areas, and link these circles with the main circle (using different colors is also another good idea). Then further out from the center of the paper put down the other relevant information relating to the topics and link these with the topic circles (see Figure 1) Each of these circles should act as a prime, so that once you have managed to remember the pictorial representation of the “to be learned” knowledge, you should then find it more easy to recall the precise information …

Give it a go and see if it helps!

Figure 1:

Weblinks

A video about Pavlov’s experiments and classical conditioning.
http://www.youtube.com/watch?v=hhqumfpxuzI
Henry Roediger speaking about doing research on the science of learning.
http://www.youtube.com/watch?v=7me7PCROc7Y
An implicit memory demo.
http://www.gocognitive.net/demo/implict-memory-test-dot-clearing
A series of videos where Robert A. Bjork talks about his research on long-term memory, learning, and adaptive memory in real life.
http://www.gocognitive.net/video?f[0]=field_interviewee%3A1183
A series of videos where Ron Rensink talks about visual attention and change blindness.
http://www.gocognitive.net/video?f[0]=field_interviewee
A demo that allows you to test yourself in the change-blindness paradigm.
http://www.gocognitive.net/demo/change-blindness
Eric Kandel on the New Science of Mind.
http://www.youtube.com/watch?v=0FjnklIwT0s

Please find below biographies of three important researchers in the field of memory: Ivan Petrovich Pavlov, Daniel L. Schacter and Eric R. Kandel.

Ivan Petrovich Pavlov

Personal history

Pavlov was born on September 14, 1849 in Ryazan, Russia. Initially, following in the footsteps of his father, the village priest, he attended Ryazan’s church school and subsequently entered the Ryazan Ecclesiastical Seminary.

Pavlov changed directions after being exposed to the work of I.M. Sechenov, the father of Russian physiology, dropping out of the seminary and enrolling at the University of Saint Petersburg to pursue his Ph.D. in the natural sciences in 1870. During his study of physiology, he published a celebrated article with a fellow student about pancreatic nerves, for which they earned gold medal honors at the university. Although he received his research degree in 1875, Pavlov chose to continue his studies at the Academy of Medical Surgery in St. Petersburg where he would eventually earn his M.D. and another gold medal, graduating in 1879. As the Director of the Physiological Laboratory in S.P. Botkin’s clinic, as well as a recipient of a competitive fellowship at the Academy, Pavlov finished his research and presented his doctoral thesis, The Centrifugal Nerves of the Heart.

Beginning a 45-year stint as the Director of the Department of Physiology at the Institute of Experimental Medicine in 1890, Pavlov helped catapult the Institute to prominence. Pavlov simultaneously accepted the post of Professor of Pharmacology at the Military Medical Academy and, in 1895, was appointed to the Chair of Physiology, which he held until 1925. Pavlov’s research, largely conducted at the Institute of Experimental Medicine, which Pavlov directed until his death, formed the basis for a series of lectures in 1895, which were published 2 years later in a collection called Lectures on the Function of the Principal Digestive Glands.

In 1881, Pavlov married a teacher and friend of Fyodor Dostoyevsky, named Seraphima Vasilievna Karchevskaya. She would suffer a miscarriage (rumored to be due to her constant dashing about to keep up with her fast-moving husband) before giving birth to four sons (one of which died suddenly in childhood) and a daughter. Initially, the couple was strained by Pavlov’s limited resources, which forced the two to live apart for awhile, but Pavlov always felt that he owed much to Seraphima’s undying devotion to him and his work.

Elected a corresponding member of the Russian Academy of Sciences in 1901, 3 years before he won a Nobel Prize in Physiology or Medicine, Pavlov would go on to be elected Academician of the Russian Academy of Sciences in 1907. In 1915 he was awarded the Order of the Legion of Honor after having received an honorary doctorate at Cambridge University. His accomplishments and contributions to the world of science were publicly celebrated by Lenin in a special government decree, signed in 1921. Despite the special privileges offered by the Soviet government, Pavlov was an outspoken opponent of Communism until the last 2 years of his life when he had a change of heart.

On February 27, 1936, Pavlov died in the city of Leningrad, a process that Pavlov asked one of his students to document so to illuminate the subjective experience of death and dying. His laboratory in St. Petersburg remains a carefully preserved museum.

Research

Pavlov’s groundbreaking work on digestion led to his Nobel Prize in 1904. Specifically, he investigated the importance of digestive organs by surgically removing selected segments from animals and implanting tubes into organs, allowing their contents to be examined (a method developed by his colleague, D.D. Glinskii).

Dividing his nonhuman experimental subjects—mainly dogs—into the four temperament types proposed under Hippocratic theory, namely phlegmatic, choleric, sanguine, and melancholic, Pavlov concluded that all groups emit the same types of responses in the face of stressful stimuli, but go through those responses at different times because their nervous systems are constructed differently. Sanguine and phlegmatic beings, with their strong and relatively balanced nervous system, were shown to be not generally excitable or inhibited. As such, they require higher levels of stress before reaching their breaking point and shutting down (called transmarginal inhibition). Interestingly, those animals with a low stress tolerance were more likely to forget conditioned responses sooner than dogs that were more calm and imperturbable. It is Pavlov’s work on conditional (or conditioned) reflexes for which he is best known.

Pavlov used a fistula, implanted into the salivary glands of dogs, in order to analyze the composition of saliva. He noticed that his dogs began to salivate when they saw the experimenters’ lab coats, even before they actually received the food powder, in what he called a “psychic secretion.” This led him to spend decades trying to characterize under what circumstances the dogs learned to form (and extinguish) conditioned reflexes, such as salivation. While Pavlov’s dogs were often cued to salivate with bells, Pavlov also employed whistles, metronomes, and tuning forks.

At the 14th International Medical Congress in Madrid in 1903, Pavlov presented a paper suggesting that the conditioned reflex is an elementary psychological and physiological phenomenon, responsible for everything from basic reflexes to the complex ways in which humans come to react to their environments. Additionally, Pavlov and his students came to show that the cerebral cortex gave rise to these conditioned reflexes. Toward the end of his life, Pavlov busied himself by attempting to link the development of various neuroses to conditioning.

It’s important to note that Edward Twitmeyer, a Ph.D. student at the University of Pennsylvania in the United States, actually reported conditioning in humans a couple of years before Pavlov announced his similar findings while accepting his Nobel. Unfortunately for the relatively unknown Twitmeyer, his dissertation work and subsequent talk at the American Psychological Association Conference in 1904 have been obscured by the notoriety given to Pavlov. Even Pavlov’s work was slow to drive research in the United States, failing to take off until John B. Watson popularized the idea of conditioning, and English translations of Pavlov’s writings became available in 1927.

References

Pavlov, I. P. (1927). Conditioned reflexes. London: Oxford UP.

Pavlov, I. P. (1928). Lectures on conditioned reflexes: Twenty-five years of objective study of the higher nervous ability (behavior) of animals. New York: International Publishers.

Pavlov, I. P. (1957). Experimental psychology and other essays. New York: Philosophical Library.

Daniel L. Schacter

Personal history

Born on June 17, 1952 in Brooklyn, New York, Daniel Schacter moved to the Westchester suburbs with his younger brother and sister, Ken and Jane, where he showed an affinity for baseball, golf, and jazz music. A high school class in psychology guided him to further study in psychology. At the University of North Carolina, Chapel Hill, Schacter focused on clinical and abnormal psychology, as well as the history of the field, eventually receiving his Bachelor’s degree in 1974. In his senior year, Schacter was introduced to experimental psychology, working in Edward Kelly’s psychophysiological laboratory at Duke University.

Before moving to Canada to attend the University of Toronto, where he earned his Master’s degree in 1977, he joined Herbert Crovitz’s perception and memory laboratory at the Durham Veterans Administration Hospital. There he studied and published findings on patients with organic memory disorders, a topic that would become a cornerstone of his future research. After spending a year at Oxford University as a visiting researcher in the department of psychology, Schacter returned to the University of Toronto to pursue his Ph.D. in psychology, under the supervision of Endel Tulving.

He received his Ph.D. in 1981 and quickly became a Research Associate and Assistant professor in the Unit for Memory Disorders and the Department of Psychology at the University of Toronto, along with Tulving and Morris Moscovitch. After 6 years there, he became an Associate Professor of psychology at the University of Arizona, where he remained until 1991, then being promoted to a full professor in the Department of Psychology and Cognitive Sciences Program in 1989, the same year he was awarded the Arthur Benton Award from the International Neuropsychological Society.

Schacter moved to Harvard University in 1991, where he is currently the William R. Kenan, Jr. Professor of Psychology, acclaimed for his accessible and engaging writing by the New York Times Book Review Notable Books of the Year (1996, 2001), the Library Journal Best Science and Technology Books of the Year (1996), Amazon.com’s Best Books (2001), and the American Psychological Association’s William James Book Award (1997, 2003). Between the years of 1995 and 2005, he served as department chair. In addition to being a highly respected (and most frequently cited researcher in psychology between the years of 1986 and 1990, according to the Institute for Scientific Information in 1992) memory researcher and prolific author, Schacter has earned praise for his teaching, receiving the Harvard-Radcliffe Phi Beta Kappa Teaching Prize in 1997.

He has published over 350 articles and book chapters and is a recipient of a Guggenheim Fellowship and the Distinguished Scientific Award for Early Career Contribution to Psychology in Human Learning and Cognition. Schacter is married to Susan McGlynn, with whom he is raising their two daughters, Hannah and Emily.

Research

Schacter’s Ph.D. work was heavily influenced by his mentor’s investigations of encoding specificity, retrieval processes, and the newly proposed distinction between episodic and semantic memory. His Ph.D. thesis delved into the feeling of knowing, though his fascination with the life and work of German biologist Richard Semon led him to eventually pen a book, Stranger Behind the Engram (later re-released in 2001 under the title, Forgotten Ideas, Neglected Pioneers: Richard Semon and the Story of Memory), about the man that coined the word “engram” and the implications of his theories of memory.

His time at the Unit for Memory Disorders provided him the opportunity to study the dissociations between explicit and implicit memory revealed by patients suffering from organic amnesia, who often have intact implicit memory. In 1985, Schacter and his colleague Peter Graf formally introduced the explicit-implicit distinction to the literature. Working with Elizabeth Glisky, Schacter attempted to develop means to help remediate memory disorders.

In 2001, Schacter delineated The Seven Sins of Memory, dividing them into the sins of omission (transience, or the decreasing accessibility of memory over time; absent-mindedness; and blocking, or the temporary inaccessibility of stored information) and sins of commission (suggestibility, or the incorporation of misinformation due to leading questions; bias, or distortions reflecting current knowledge and beliefs; persistence, or unwanted recollective intrusions that people are unable to forget; and misattribution, or being unable to appropriately attribute a piece of information to its appropriate source). Although these sins aren’t always flaws, he described them as side-effects of the memory machinery upon which we rely.

Adding to Schacter’s previous work with amnesic patients, he is advancing the neuroimaging of memory with fMRI and PET to better understand the neural substrates of correct and false memory, how memory is used to imagine future events, and age-related memory effects.

References

Schacter, D. L. (1982). Stranger behind the engram: Theories of memory and the psychology of science. Hillsdale, NJ: Lawrence Erlbaum Associates.

Schacter, D. L. (1987). Implicit memory: History and current status. Journal of Experimental Psychology: Learning, Memory, and Cognition, 13, 501–518.

Sherry, D. F., & Schacter, D. L. (1987). The evolution of multiple memory systems. Psychological Review, 94, 439–454.

Schacter, D. L., Reiman, E., Uecker, A., Polster, M. R., Yun, L. S., & Cooper, L. (1995). Brain regions associated with retrieval of structurally coherent visual information. Nature, 376, 587–590.

Schacter, D. L., Alpert, N. M., Savage, C. R., Rauch, S. L., & Albert, M. S. (1996). Conscious recollection and the human hippocampal formation: Evidence from positron emission tomography. Proceedings of the National Academy of Sciences, 93, 321–325.

Schacter, D. L. (1996). Searching for memory: The brain, the mind, and the past. New York: Basic Books.

Schacter, D. L. (2001). The seven sins of memory: How the mind forgets and remembers. Boston and New York: Houghton Mifflin.

Slotnick, S. D., & Schacter, D. L. (2004). A sensory signature that distinguishes true from false memories. Nature Neuroscience, 7, 664–672.

Dobbins, I. G., Schnyer, D. M., Verfaellie, M., & Schacter, D. L. (2004). Cortical activity reductions during repetition priming can result from rapid response learning. Nature, 428, 316–319.

Eric R. Kandel

Personal history

Born on November 7, 1929 in Vienna, Austria into a middle-class Jewish family, Kandel’s life and research was heavily influenced by his early childhood experiences. When he was only 8 years old, Nazi Germany annexed Austria in March 1938, forcing his family to leave the country in the face of Jewish persecution. A year later, Eric and his older sibling, Ludwig, fled to Brooklyn, where they stayed with their uncle until their parents later made it to the United States.

Trained in Judaic studies by his grandfather, Kandel enrolled in the Yeshivah of Flatbrush and then Erasmus Hall High School where he became sports editor of his school newspaper, played soccer, and was co-captain of his track team. He majored in twentieth-century European history and literature at Harvard University, where he presented his honors dissertation entitled, The Attitude Toward National Socialism of Three German Writers: Carl Zuckmayer, Hans Carossa, and Ernst Jünger. During his undergraduate career—and thanks largely to his relationship with Anna Kris, a daughter of Freudian psychoanalysts—Kandel also became interested in Freudian analysis. Then matriculating at the New York University Medical School in 1952, Kandel initially was intent on becoming a psychoanalyst, but decided to study the biology of memory after taking a course on neurophysiology.

Unable to find a laboratory meeting his interests at NYU, he took an elective period at Columbia University, working with neurobiologist Harry Grundfest. It was at Columbia that Kandel met Denise Brystryn, a French Ph.D. student in medical sociology, whom he would later marry when he gradated with his M.D. in 1956. He interned at Montefiore Hospital while waiting for his wife to graduate before moving to the Laboratory of Neurophysiology at the National Institutes of Health and later a residency in psychiatry at Harvard Medical School. In 1962, Kandel visited Paris where Ladislav Tauc introduced him to the Aplysia californica, which would become the primary subject of much of Kandel’s later work.

After accepting the post of staff psychiatrist at Harvard Medical School in 1964, Kandel began a 9-year tenure in the Departments of Physiology and Psychiatry at New York University in 1965. Since 1974, Kandel has been a professor in the Department of Physiology and Psychiatry and the Department of Biochemistry and Molecular Biophysics at Columbia University. During this time, he helped establish the Howard Hughes Medical Research Institute at Columbia, with its mission to explore molecular neural science, where he is currently senior investigator.

In addition to his Nobel Prize in Physiology or Medicine for his work on the neural basis of memory storage, awarded in 2000, Kandel has won: the National Medal of Science and a Gold Medal for Scientific Merit, both in 1988; the Charles A. Dana Award for Pioneering Achievement in Health and the Gerard Prize for Outstanding Achievement in Neuroscience, both in 1997; Israel’s Wolf Prize in 1999; and the 2006 Los Angeles Times Book Award for Science and Technology for In Search of Memory: The Emergence of a New Science of Mind—to name just a few.

Research

While in medical school, Kandel began working with Harry Grundfest at Columbia University, attempting to record the electrical activity of hippocampal neurons in mammals. This proved a difficult challenge, given the synaptic density of the mammalian brain. Thus, after graduating from medical school, Kandel endeavored to use microelectrodes to obtain intracellular recording of much simpler marine life, such as crayfish. At the National Institutes of Health, he and Alden Spencer managed to record a combination of spontaneous action potentials and recurrent inhibition in hippocampal neurons.

Determined to better understand how modifications in the strength of synaptic connections between neurons might be the basis of Hebbian learning but again frustrated with the inherent complexity of mammalian neural structure, Kandel set about forming an animal model of simple learning processes by studying ganglia from the sea slug, Aplysia. His choice to research an invertebrate became the subject of ridicule by his colleagues who felt that mammalian memory processes could not be understood without studying mammals directly. However, Kandel’s risk eventually paid off. By repeatedly applying an electrical stimulation to two separate ganglion cells, representing the conditioned and unconditioned stimuli in a classical conditioning paradigm, he witnessed gradual changes in the synaptic activity between them that could then be extinguished.

Thus, Kandel had found evidence that short-term memories are formed through the modulation of existing synapses. He then went on to learn that the addition of phosphate groups were responsible for these changes.

Kandel’s work with the Aplysia’s gill-withdrawal reflex, in which the gill tissue recoils in the face of danger, was shown to be influenced both by habituation (in which synaptic connections were lost) and sensitization (in which new connections were made). In the 1990s Kandel extended his findings for short-term and long-term implicit memories in the fear response of mice. This painstaking research helped cement Kandel’s discovery that long-term memories are maintained through the activation of certain genes promoting the synthesis of proteins that create new synaptic connections, and earned him a share of the 2000 Nobel Prize in Physiology or Medicine.

More recently he has been studying the episodic (spatial) memory capabilities of genetically modified mice in order to characterize the neural processes responsible for memory impairments related to dementia and other illnesses. This research not only revealed the importance of inhibition, in addition to activation, for effective memory storage, but also continues to yield promising targets for new drugs aimed at helping those afflicted with memory disorders.

References

Kandel, E. R., Schwartz, J., & Jessel, T. (1991). Principles of neural science. New York: Elsevier.

Squire, L. R., & Kandel. E. R. (1999). Memory: From mind to molecules. New York: W. H. Freeman & Co.

Kandel, E. R. (2006). In search of memory: The emergence of a new science of mind. New York: W. W. Norton.