Harvard professor discusses power of human memory

By Suzanne Johnson, Online Forty-Niner

Monday, November 16, 1998

It may seem ironic to refer to memory as a fragile power, but it is not inaccurate, according to Daniel Schacter, a professor of psychology at Harvard University and author of "Searching for Memory."

Schacter discussed building memory through encoding processes, the fragility of memory and the multiple forms of memory during his Odyssey presentation Tuesday.

Schacter referred to William Jefferson Clinton in his introduction as a well-known amnesiac with an immense potential for forgetting.

The differences in recall of the same object suggests that encoding processes play a significant role in memory, Schacter said.

The mind does not operate like a camera, Schacter said. People pay selective attention to aspects in their environment and relate those specifics to their prior knowledge.

Schacter defined three levels of encoding: structural, phonemic and semantic.

Experiments have revealed that memory is at its best after an individual has advanced to the semantic level, he said.

Neuro-imaging techniques have helped scientists understand the brain by showing the changes in blood flow and oxygenation in the brain regions most active during cognitive tasks, Schacter said.

"The issue of accuracy and distortion is one psychologists have long been interested in," Schacter said. It is receiving renewed interest due to the debate over recovered memories, he said.

Experiments reveal that older individuals have higher incidents of false recall and false recollection.

Schacter relayed an observation made by Mark Twain who said when he was younger, he could remember anything whether it had happened or not. As he aged however, he was only able to remember what had not happened.

"Conscious recollection is only one domain of memory," Schacter said. Memory is not a unitary entity, it encompasses both explicit and implicit memory, he said.

Explicit memory is a conscious and intentional recollection of past events whereas implicit memory is the unconscious and unintentional influence of past events on current recollection.

Memories of Holocaust survivors are a powerful testimony to the importance of not losing contact with the past, Schacter said.

Memories underlie our sense of self and define who we are, he said.