Thursday, December 29, 2016
It is well known that stress can impair memory. Everyone has had some experience of this kind. As a student suffering test anxiety, grades are likely to suffer. In high-stakes social or business interactions, the stress may well cause memory to fail us, as when Presidential candidate Rick Perry forgot the name of the agency he wanted to abolish if elected, or when we forget a friend’s name in the process of making a social introduction. How does stress do this? Is there anything we can do about it?
First, we need to know what stressful events do to the body and brain. Brain freezes, like Rick Perry's, probably occur because thinking can get so preoccupied with the stress-inducing stimuli that other thoughts cannot emerge. But other kinds of stress-induced memory impaired come from the well-known “fight or flight” response in which stress activates the release of adrenalin into the blood stream. Adrenalin has many bodily effects that support fight or flight, such as raising heart rate and blood pressure, and increasing arousal perhaps to the point of anxiety and fear. The increased attentiveness may have a fleeting beneficial effect on memory, as has been demonstrated in laboratory experiments. But the other effects of adrenalin on anxiety and distress are likely to impair memory.
The other thing that happens during stress is the activation of the anterior pituitary gland’s release of ACTH, which in turn activates another part of the adrenal gland to dump cortisol into the blood stream. In the short term, cortisol can have many beneficial effects for combatting stress, such as mobilizing white blood cells and enhancing the immune system. But cortisol binds to cells in the brain’s hippocampus, the area that converts new experiences into memory. This binding actually disrupts the memory-forming process. Ultimately, if stress continues, the synaptic regions deteriorate, making the impairment permanent.
The effects of both adrenalin and cortisol were revealed in an interesting study of mild social stress. Here, the focus was on a theory of how stress effects on memory might be thwarted by a learning technique called forced retrieval. Prior research with students, had shown, that the usual study technique of re-reading notes or text is not nearly as effective as requiring the learner to actively retrieve the information, as one might do, with flash cards, for example. Just a few months ago, I posted a blog on this forced retrieval phenomenon as a key element in “strategic studying.”
This new research was aimed at testing the possibility that forced retrieval might protect learners from the memory deficits caused by stress. In the study on the first day, 120 subjects studied a list of 30 nouns or images of nouns one at a time. Then, one half of the group restudied the items while the other half practiced retrieval by recalling as many items as they could (but without feedback telling them if they got it right). One the next day, half of each group were stressed by being required to solve hard math problems and by giving speeches in front of two judges and three peers. Then they were tested. Twenty minutes later they took a second test on items that had not been tested on the first test. The results revealed that retrieval practice yielded better results.
On the first test, we see that the stressed learners who just studied the items the day before had fewer of the items remembered on the first test given immediately after the stress. But there was no such effect on the stressed leaners who used retrieval practice during the initial learning. This protective effect of retrieval practice was evident on the second test 25 minutes later. In fact, the retrieval practice effect was better than on the first test, even though different items were tested. You may have noticed that the stressed study group on the second test did worse than they did on the first test. This is attributed to a mild effect of adrenalin, which as mentioned above can have some benefit on memory. Adrenalin’s action is immediate and is apparently swamped on the second test by the delayed release of cortisol, which shows up by the second test. Students might note that the magnitude of difference may appear small, but in percentage terms could equal to more than two letter grades (compare the two stressed groups on the delayed test).
To explain why forced retrieval works, the authors speculate that it provides better initial encoding. That is, the new information is registered more strongly if you make yourself try to retrieve it. This is consistent with the everyday experience that most of us have had wherein information that strongly grabs our attention is more likely to be remembered. Forced retrieval is a way to make ourselves pay better attention to what we are trying to lean.
Readers wanting to learn more about improving memory are urged to check “Memory Medic’s” books, Memory Power 101 and Better Grades, Less Effort.
Klemm, W. R. (2016). Strategic studying. October 9, http://thankyoubrain.blogspot.com/2016/10/strategic-studying.html
Smith, Amy M. et al. (2016). Retrieval practice protects memory against acute stress. Science. 354 (6315), 1046-1047.
Saturday, December 10, 2016
Everyone has feelings about those who have been close to them: parents, siblings, spouses, and colleagues. Those feelings are usually formed from memories of past interactions with those people. When those memories are negative, they can poison relationships and lead to terrible results: family feuds, alienated siblings, estrangement between children and parents, divorce, law suits, and assorted vendettas. The saddest part of all is that research is showing that many of these negative memories can be wrong.
Memories are seldom fully literal. Memories are constructed, not recorded like an audio tape. The brain decides how an experience is to be packaged as a narrative to remember. We even generate fictions for experiences that do not involve our own inter-personal relationships. Witness the conflicting stories about how many planes struck the World Trade Center or about the Ferguson "hands up, don't shoot" imagined incident. The criminal justice system now downplays eye-witness testimony because so much of it in the past has proven unreliable. Often this happens when experiences are intense and complex, causing the over-taxed brain to jam them unthinkingly into its already formed store of memories.
Construction of false memory is especially likely during childhood, for several inevitable reasons:
· Children do not process reality as readily or correctly as adults.
· The brain circuitry of children changes dramatically as brains grow and re-wire, which causes many memories to be lost or corrupted.
· Constant replay of the memory over the years leads to further alteration of the memory and the repetition confirms the memory, even when it is wrong.
A recent article in the Wall Street Journal says that we categorize memories to help define ourselves. The author says this is a good thing because it is a method for bolstering one's ego. We may, for example, construct memories to help us think of ourselves as superior, righteous, or likable. But others will construct memories that confirm a pre-existing low self-esteem, thinking of oneself as a victim, incorrigible, unlikable, or whatever. This is a well-studied phenomenon that psychologists call confirmation bias. For better or worse, we transform real experiences into memories that are a "creative blend" that mixes fact and fiction.
When we construct memories that put a negative spin on past interactions with others, we build a negative attitude toward them. Negative attitudes about others are hard to hide. Then as subsequent relationship experiences occur, they too get the negative spin, adding to the storehouse of false memories that can grow into hostility. Rubbing salt into mental wounds by rehearsing grievances year after year intensifies the memory and reinforces belief in it. Apologies and forgiveness become harder and harder to generate.
Why does the brain work this way? A Harvard study revealed that the same areas of the brain are used for remembering past events and imaginary events. A University of Dayton study showed another reason: people have an unconscious incentive to create false memories to protect themselves from threats to their beliefs about themselves. As a relatively benign example, college students who opposed increased tuition, after writing an essay that required them to defend a tuition increase, mis-remembered their initial opposition.
More serious consequences result when, as a Northwestern U. psychology professor explains, people exaggerate the negativity or misery of past experiences to impress themselves and others by their endurance of suffering or "escape" from it. Such exaggeration also occurs as responses to real-time events, as for example when people put the worst possible spin on a current experience. It makes them seem to be a bigger victim and coping with it seems like a bigger achievement.
A University of Utah psychologist says false memories take on more meaning and apparent justification when recounted to others. So as if the false memory were not bad enough, we use it to poison the reputation of others. A child who thinks parents or siblings were unfair, gains validation by telling friends about the presumed mistreatment. A worker may put a negative spin on an annual review and may feel better if he uses that memory to discredit the boss in the eyes of others.
The damage in such cases is three-fold: 1) lying to oneself prevents dealing with real solutions, 2) damaging the reputation of others is mean-spirited and unjust, and 3) spreading this kind of falsehood ultimately destroys the reputation of the perpetrator.
"Bury the hatchet" is sound advice. The more promising way to have good relationships is to base them on the present and to nurture them in positive ways for the future.
Dr. Klemm is author of the recent book,
Mental Biology (New York: Prometheus).
Krokos, Dan. (2012). False Memory. New York: Hyperion.
Shellenbarger, Sue (2016). How inaccurate memories can be good for you. Wall Street Journal. July 27.