Shocking! Being scared enhances memory

WASHINGTON U.-ST. LOUIS (US) — A jolt of fear from viewing frightening or devastating images reinforces memory, but pleasant ones don’t have the same effect.

While it may be counterintuitive, a new study finds viewing emotion-laden pictures immediately after taking a test actually enhances retention of the tested material.

“Memory is labile and dynamic—after you retrieve something, you’re still engaged in processing that information in some way,” says Bridgid Finn, postdoctoral researcher in psychology at Washington University in St. Louis.

“Having a picture of a gun pointed at you just after you’ve just been tested on something probably isn’t the best situation for learning, but because there is an intricate relationship between areas involved in emotion and remembering, the amygdala and the hippocampus, we find that the negative picture can enhance later retention.”

The research is published in the journal Psychological Science.

For the study, 40 undergraduate students studied 10 lists of 10 pairs of Swahili-English vocabulary items (lulu/pearl; ubini/forgery) and were given a cued recall test after studying each set of 10 pairs and then given a final test on all 100 pairs.

On the initial test, following each correct answer, they were shown a picture either of a negative emotional image, such as a pointed gun; a neutral image, such as a chair; or a blank screen. The participants then did a one-minute multiplication test as a sort of mental palette cleansing to remove the effects of short-term memory, like a serving of sherbet in a multiple-course meal.

On the final cued-recall test on all 100 Swahili-English items, participants performed the best on items that had been followed by negative pictures.

This initial experiment showed that the process involved in retrieving an item does not end when that item is retrieved. In a second experiment designed to explore the limits of the enhancement effect, the researchers tested a second group of students who viewed the images two seconds after successful retrieval.

The question: Does the retrieval process persist during those two seconds? “The answer appears to be yes, the students continue to process the information during the two-second pause,” Finn says.

A third study of 61 students was intended to rule out the possibility that arousing images simply made certain pairs of words seem more distinct and thus made them easier to remember. This experiment was similar to the other two with one major distinction: Instead of taking the initial tests, participants restudied the items.

“For negative emotion to enhance later retention of something, this experiment shows that you have to retrieve that information,” Finn says. “That is, you have to go get it. In the absence of retrieval, the negative pictures do not enhance later performance. That’s critical.”

Gender did not factor into the participants’ success rate and physiological parameters such as adrenaline or hormonal responses were not used as a measure.

Positive images don’t enhance retrieval or retention. Preliminary data on a study of participants who were tested on items that were followed by sexually arousing images show no learning enhancement. While the pictures were arousing, they weren’t linked to enhanced retrieval on the later test. “Positive content, so far, doesn’t seem to be doing the trick,” Finn says.

“We’ve established that the period after retrieval is key in retaining information,” Finn says. “We want to build on that foundation and explore it in-depth.

“We want to see what kinds of manipulations can possibly be introduced in the post-retrieval phase to understand when enhancement or impairment of retention might occur.”

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