The Brain: Forgetting So We Remember, Avoiding Overload

Nov. 29, 2012 — -- We accumulate so many memories that it's a wonder our brains don't clog, strangling us on the trivia of our daily lives. How do we recall the memories that are important to us without flooding our brains with the details of every insignificant event? How do we separate the memories we need from the mountains of garbage?

According to ongoing research, we separate the wheat from the chaff by shutting down some memories, at least temporarily, to allow that one chosen treasure to resurface. In short, we forget, so we can remember.

New research into "retrieval-induced forgetting," an awkward phrase that is easily forgotten, is reshaping much of what we have known about how memories are organized and retrieved. Psychologists Benjamin C. Storm of the University of California, Santa Cruz, and Robert A. Bjork of UC Berkeley, along with other cognitive scientists around the world, have produced some potentially game-changing results.

In laymen's language, the research suggests the healthy human brain comes equipped with something like a super-smart Web browser. A cue that should trigger the retrieval of a specific memory also allows the browser temporarily to suppress many memories that are similar to the target, but not precise enough.

The beauty of such a system, if it continues to be validated by other research, is that it would allow us to recall positive memories, which we prefer over negative memories, so every cue doesn't dredge up sad or heartbreaking remembrances. Yet even the saddest memories remain buried in our brains, and the temporary suppression that keeps them from constantly resurfacing doesn't bury them forever. They are suppressed, but not totally forgotten.

The research is based chiefly on word association. A cue of automobile-red, for example, may remind someone of their father's red Oldsmobile, but not necessarily of the tragic accident that killed him.

Storm and a colleague, Tara A. Jobe of the University of Illinois at Chicago, conducted a series of experiments, and report the results in the current issue of the journal Psychological Science. The first experiment allowed them to determine how efficient each participant was at suppressing -- or forgetting, as they prefer to call it -- some memories to facilitate recalling a specific memory. Surprisingly, the participants were unable to recall word associations they had practiced as well as words they had not practiced, indicating some inhibiting mechanism was at work.

That experiment allowed them to evaluate each participant's level of "retrieval-induced forgetting." Those who scored well had an especially effective "browser," while others were only mediocre, and some were even weaker.

The participants were then instructed to recall an autobiographical memory -- something that they experienced personally.

"There is a positivity bias in autobiographical memory such that people are more likely to remember positive events from their past than they are to remember negative ones," the scientists said, and much other research supports that.

The memories recalled by the participants suggest a very significant role for "retrieval-induced forgetting."

"Participants who exhibited lower levels of retrieval-induced forgetting (weak browser) recalled significantly more negative memories" than participants with a strong browser, the study concluded.