Particularly Exciting Experiments in Psychology

Having a good memory is typically viewed as being highly desirable. Indeed, people often actively work to improve their memory. At the extreme, there is an annual World Memory Championship, in which people compete by memorizing, among other things, as many digits in pi as they can.

The benefits of excellent memory are obvious because people rely on memory on a regular basis — to remember the grocery list, the name of a new colleague, or the location of the car keys. But recent research suggests that there are situations in which forgetting, not remembering, is advantageous.

For example, forgetting can be beneficial for real-world associative learning. Multiple cues may be present in the environment at any given time, even if they do not have a meaningful relationship. Thus, successful learning involves both learning true relationships and forgetting random relationships that do not have predictive value.

Gonzalo, López, and Martín (2013, Journal of Comparative Psychology) (PDF, 107KB) tested this kind of adaptive forgetting in Iberian green frog tadpoles. Tadpoles were exposed to a neutral chemical cue (derived from zebra fish) paired with an alarm cue (a chemical cue derived from dead tadpoles). Tadpoles were then tested on a separate day with either the zebra fish cue or clean water.

Tadpoles tested with the zebra fish cue exhibited less movement than did those tested in clean water, demonstrating that they had learned to recognize that the zebra fish cue signaled danger when it was previously paired with an alarm cue (moving less in the presence of a predator helps tadpoles avoid detection).

In a subsequent experiment, tadpoles were exposed to the zebra fish cue–alarm cue pair, followed by separate sequential exposures to the zebra fish and alarm cues alone. In this case, there were no differences in behavior between the tadpoles tested with the zebra fish cue and those tested in clean water.

In other words, exposure to the two cues independent of each other caused tadpoles to forget any learned association between the zebra fish cue and the alarm cue formed during the paired-exposure phase. This ability to avoid learning irrelevant information is beneficial because it prevents tadpoles from exhibiting maladaptive or costly antipredator behavior in the presence of nonpredators.

Forgetting has also been shown to be beneficial in a very different domain: creative thinking. Storm and Patel (2014, Journal of Experimental Psychology: Learning, Memory, and Cognition) (PDF, 155KB) presented participants with four uses for common household objects (e.g., newspaper: paper mâché, gift wrapping, start a fire, tablecloth).

On baseline trials, participants were simply instructed to study the uses. On thinking trials, participants studied the list and then had one minute to generate new uses for the object. In the subsequent test phase, participants were shown the name of each household object and were asked to list the four studied uses.

Participants remembered fewer studied uses in the thinking condition than in the baseline condition, suggesting that thinking of new uses caused participants to forget studied uses. However, participants who experienced greater thinking-induced forgetting (e.g., a greater memory deficit on thinking vs. baseline trials) generated new uses that were rated more creative than the uses suggested by participants who experienced less thinking-induced forgetting.

Moreover, there was a significant correlation between the magnitude of the thinking-induced forgetting effect and the number of generated creative uses but not the number of generated noncreative uses. The authors suggested that forgetting may promote the ability to think creatively by making information that is no longer useful less accessible, so it does not interfere with access to new information or ideas.

Together, these studies demonstrate that forgetting can have very diverse kinds of benefits across a wide range of domains.

Other Interesting Reading

• Stahl et al. (2014, Journal of Experimental Psychology: General) demonstrated that impulsivity in human adults consists of five correlated but separable behavioral components.
• Mitchell et al. (2014, Behavioral Neuroscience) showed that cocaine-induced neural adaptations promote the development of impulsive decision making in male Long-Evans rats.

The table below illustrates the three phases of Pavlovian (classical) conditioning.

Before Conditioning	unconditioned stimulus (food) > unconditioned response (drool) neutral stimulus (bell) > no response
During Conditioning	neutral stimulus (bell) + unconditioned stimulus (food) > unconditioned response (drool)
After Conditioning	conditioned stimulus (bell) > conditioned response (drool)

• Recreate this table and replace with the cues and responses (in bold) with those from the experiment in Gonzalo et al. where tadpoles learned to move less in the presence of the zebra fish cue.
• Storm and Patel suggest that forgetting renders old information less accessible, so it does not interfere with retrieval of new information. How does this hypothesis explain their finding that forgetting studied uses leads participants to generate more creative uses for common objects?

• Find one media article about an individual with extraordinary memory.
• Write a one paragraph summary of the article.
• What kind of memory does the person excel at?
• Does the person report using any heuristics?

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