Can We Control What We Remember?

Clifford Robbins '10 and Sarah Bookbinder '10
Clifford Robbins '10 and Sarah Bookbinder '10
“In general, we are least aware of what our minds do best.” Marvin Minsky, an American cognitive scientist, said it succinctly and with due reason. Psychologists still do not know much about memory. Do we have control over what we remember? Sarah Bookbinder ’10 and Clifford Robbins ’10 are researching directed forgetting, a method for thought control in which participants are told to forget previously learned material. This summer they will try to determine the method’s effectiveness with Visiting Professor of Psychology Mark Oakes.

Bookbinder and Robbins are using what is called the “list method paradigm of directed forgetting.” Subjects are presented with a list of words and then given a cue to forget or remember it. Previous studies have focused on the “gist” of the words – that is, subjects recite the words based on their memory of the semantic concepts they convey. But this study will reach further into consciousness by testing the ability to recall details. The students will also ask how a higher working memory capacity might contribute to a larger directed forgetting effect.

Bookbinder will carry out several experiments using the list method. In one experiment, the participant will view lists of compound words such as “blackmail,” “grapefruit,” or even obscure words like “steeplechase.” The researchers will then present half of a word to see if the participant recognizes it as part of the whole or as two separate words. Synonyms and thematically-related words may jolt a person’s memory of the “gist,” rather than the detail, of a previous list. This might cause him to remember words that he didn’t actually hear.

She will also test the role of working memory (temporary storage of accessible information) through the list method, but this time, there’s a catch. Participants will have to perform an “N-back” test simultaneously. Words and numbers will appear alternately on a screen – the words make up the directed forgetting test, while the numbers are from the “N-back” test. While keeping in mind what words have flashed on the screen, participants will have to alert the test administrator as to when the present number matches the one from n steps earlier in the sequence.

Robbins is working on a portion of the project that is slightly different. His is similar to Bookbinder’s, but in place of words, he will use images with varying levels of detail. He presents a series of 18 consecutive scenes followed by an instruction to either forget or remember them. After the instruction, he presents a second group, followed by a recall test in which participants list as many themes as they can remember.

A machine called the ASL 6000 eye tracking unit will offer insight as to how details are encoded in the brain after a person is instructed to forget. Previous studies have shown that we are unaware of eye movements that occur in the first one or two seconds of visual interpretation of data. The ASL 6000 will help the researchers monitor these implicit eye movements. For instance, if they give six details in the first picture, and then five during the recognition stage, will the participant immediately see that something is missing? The machine will answer this and whether or not they look for something that was present in the first presentation, but absent in the second.

“We’re looking for the qualitative difference in how we visually assess what we have seen, or think we have to have not seen,” Robbins said.

Both students hope to go to graduate school after Hamilton. Regarding the nature of research, Robbins said, “There is a load of literature out there, and each take on a topic adds a different spin. This experiment offers another perspective that no one else has looked at yet.”
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