Unpredictability Improves Memory Recall

Memory training with unpredictable components could be more effective in enhancing episodic memory than training with predictable elements, according to new findings from UT Dallas researchers published in the journal Frontiers in Psychology.

Episodic memories are those associated with autobiographical events, such as a past birthday party or first trip to an amusement park. This type of memory is crucial to our ability to accurately retell stories.

Dr. Chandramallika Basak, assistant professor at UT Dallas’ Center for Vital Longevity (CVL), and graduate student Margaret O’Connell tested episodic memory in 46 adults between the ages of 60 and 86 at three different stages: before memory training, immediately after training and one and a half months after completing the training. Participants were separated into two groups — predictable training or unpredictable training — and did not differ in terms of education or cognitive abilities.

For both groups, sequences of digits in different colors were presented. Participants were asked to indicate when the color of the current digit matched an earlier one of the same color. In training that involved a predictable element, the changing colors occurred in a fixed order, whereas the color switching was random in the training that involved unpredictability.

“Completing the task when the color changes occur unpredictably requires more cognitive resources, or control,” said Basak, who directs the Lifespan Neuroscience and Cognition Laboratory at CVL. She likens the effect to what happens when you take a new, previously uncharted way home from work. The cognitive demands required to navigate new landmarks that are part of the journey increase with the new route’s unpredictability.

The two groups of participants demonstrated equivalent story recall before training, but the group given training with the unpredictable element was able to narrate a previously heard story more accurately than the other group. That benefit, however, appeared to fade when the same group was tested a month and a half later.

“Training-related improvements from our novel approach dissipated when performance was tested awhile after completion of the training,” Basak said. “This could be a case of use it or lose it — that the training must be sustained. Future research could investigate if booster training may help with retaining the long-term benefits.

“Studies such as this one shed light on the role of cognitive control in memory training. They also highlight the differences in training-related performance gains between people, and could help researchers and clinicians develop better cognitive training strategies for older adults who are at risk for dementia.”

The findings support Basak’s hypothesis — her theory of working memory adaptability — which posits that switching between items in working memory involves cognitive control, and that different types of cognitive training regimens can influence demands on cognitive control.

Image shows a multi colored brain.

For both groups, sequences of digits in different colors were presented. Participants were asked to indicate when the color of the current digit matched an earlier one of the same color. In training that involved a predictable element, the changing colors occurred in a fixed order, whereas the color switching was random in the training that involved unpredictability. Image is for illustrative purposes only.

Working memory involves the ability to keep information in the focus of attention and to manipulate or reorder it despite distractions — the sort of mental juggling required in everyday life, she said.

“When you have multiple items to remember, you need to focus your attention on what is most relevant and up-to-date, setting aside what may be distracting,” Basak said. “Such focusing of attention is more challenging when cues appear in an unpredictable order, thus requiring more cognitive control. It seems from our study that improving the efficiency of focusing attention to the target using unpredictable training strategy led to more accurate episodic memory.”

About this memory research

Funding: The research was supported by funds from UT Dallas’ Faculty Research Initiative.

Source: Alex Lyda – UT Dallas
Image Source: The image is in the public domain.
Original Research: Full open access research for “To Switch or Not to Switch: Role of Cognitive Control in Working Memory Training in Older Adults” by Chandramallika Basak and Margaret A. O’Connell in Frontiers in Psychology. Published online March 2 2016 doi:10.3389/fpsyg.2016.00230


Abstract

To Switch or Not to Switch: Role of Cognitive Control in Working Memory Training in Older Adults

It is currently not known what are the best working memory training strategies to offset the age-related declines in fluid cognitive abilities. In this randomized clinical double-blind trial, older adults were randomly assigned to one of two types of working memory training – one group was trained on a predictable memory updating task (PT) and another group was trained on a novel, unpredictable memory updating task (UT). Unpredictable memory updating, compared to predictable, requires greater demands on cognitive control (Basak and Verhaeghen, 2011a). Therefore, the current study allowed us to evaluate the role of cognitive control in working memory training. All participants were assessed on a set of near and far transfer tasks at three different testing sessions – before training, immediately after the training, and 1.5 months after completing the training. Additionally, individual learning rates for a comparison working memory task (performed by both groups) and the trained task were computed. Training on unpredictable memory updating, compared to predictable, significantly enhanced performance on a measure of episodic memory, immediately after the training. Moreover, individuals with faster learning rates showed greater gains in this episodic memory task and another new working memory task; this effect was specific to UT. We propose that the unpredictable memory updating training, compared to predictable memory updating training, may a better strategy to improve selective cognitive abilities in older adults, and future studies could further investigate the role of cognitive control in working memory training.

“To Switch or Not to Switch: Role of Cognitive Control in Working Memory Training in Older Adults” by Chandramallika Basak and Margaret A. O’Connell in Frontiers in Psychology. Published online March 2 2016 doi:10.3389/fpsyg.2016.00230

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