Reference: Banks, J. B., Welhaf, M. S., & Srour, A. (2015). The protective effects of brief mindfulness meditation training. Consciousness and Cognition, 33, 277-285.
Working memory is the cognitive system that mentally maintains and processes information relevant to your current goal or task. For example, if you had to mentally manipulate several pieces of information to solve a problem, you would be using your working memory. It is usually advantageous to be able to keep more information in mind for processing; that is, a larger working memory “capacity” (or ability) is usually associated with better problem-solving and reasoning abilities. Working memory capacity has been shown to decrease when experiencing stress, negative emotions, or off-task thinking, as well as to increase following mindfulness meditation.
Mindfulness meditation is a centuries-old practice intended to calm and stabilize the mind. Mindfulness practices can take many diverse forms but generally involve (1) bringing attention to one’s present-moment experience and (2) observing this experience in an accepting, non-evaluative way. Mindfulness meditation has been demonstrated to decrease stress, negative emotions, and off-task thinking as well as to increase the ability to sustain, focus, and monitor attention.
Jonathan Banks, Matthew Welhaf, and Alexandra Srour from Nova Southeastern University investigated if brief mindfulness meditation could increase working memory capacity, as well as buffer it from decrements due to stress and off-task thinking. Eighty meditation-naïve undergraduate students were recruited and randomly assigned to either a mindfulness meditation or relaxation group. The mindfulness meditation group listened to a 15-minute recording of a guided meditation that instructed them to (1) anchor their attention to the present moment by focusing on the sensations of breathing and (2) non-judgmentally observe any thoughts, feelings, or sensations that arose and then to gently return their attention back to their breathing. The relaxation group listened to a 15-minute recording that guided them to focus on bodily sensations and progressive muscle relaxation.
The relaxation group was used to control for expectancy effects and relaxation effects that could potentially account for improvement in working memory capacity. Expectancy effects refer to differential expectations of improvement between experimental groups; this can result in one group becoming more engaged in and exerting more effort during practice and posttests. Relaxation effects refer to a temporarily induced state of calm and peace; mindfulness often induces relaxation and the researchers wanted to isolate the effects of relaxation from the effects of present-focused, non-judgmental attention.
Both the mindfulness meditation and relaxation groups were measured on several outcome variables. Working memory capacity was measured by the operation span task, in which participants must mentally maintain information (i.e., 3-7 letters) during ongoing task processing (i.e., verifying the accuracy of interleaved math equations). Mind-wandering probes were also included in this task to measure off-tasking thinking: participants were intermittently asked to report the current contents of thought and these reports were rated as on-task thoughts or off-task thoughts. Participants also completed a writing stressor in which they elaborated on a current life event that was associated with negative emotions. The idea behind this writing activity was to induce stress in participants and promote off-task thinking during the working memory task (i.e., thinking about the current life event rather than the working memory task).
Hypothetical trial example of the operation span task used to measure working memory capacity in Banks, Welhaf, and Srour (2015). Participants must verify whether a math equation is accurate (i.e., process information) and then remember a letter (i.e., maintain information). After several repetitions, the participant attempts to sequentially recall all the letters they most recently encountered.
The experiment took place over 8-11 days. The procedure was as follows: Participants first completed baseline working memory, mind-wandering, and mood measures (Time 1), listened to a 15 minute recording (meditation or relaxation, depending on group), completed outcome measures a second time to assess potential changes from baseline (Time 2), completed a week of at-home practice using their group’s 15 minute recording, returned to the laboratory and completed outcome measures again (Time 3), completed the writing stressor to induce stress, negative emotions and off-task thinking, and then completed the outcome measures a final time (Time 4). The researchers hypothesized that the mindfulness meditation group would show improved working memory capacity and reduced off-tasking thinking at Times 2, 3, and 4 compared to the relaxation group.
The researchers’ hypotheses were partially supported. The meditation and relaxation groups did not differ in working memory capacity or off-task thinking at Times 1, 2, or 3. In other words, neither a single mindfulness meditation nor a week of at-home practice was sufficient to increase working memory capacity or decrease off-task thinking.
The critical finding came after the writing stressor (i.e., Time 4). The writing stressor was successful at inducing negative emotions, based on reports from both groups. However, only the relaxation group’s working memory capacity suffered. As predicted, the relaxation group’s performance declined after the writing stressor whereas the mindfulness meditation group showed stable working memory performance before and after the stressor. Put differently, brief mindfulness meditation practice protected working memory capacity from decrements due to stress.
Also at Time 4, the groups did not differ in the rate of off-tasking thinking, but there was a negative relationship between off-tasking thinking and working memory capacity in the relaxation group (i.e., as off-tasking thinking increased, working memory capacity decreased and vice versa). That is, mindfulness meditation appeared to change the relationship between stress, off-task thinking, and working memory capacity. The researchers believed this effect was due to mindfulness meditation reducing reactivity to repetitive, task-unrelated thoughts. Instead of actively suppressing unwanted thoughts – which is thought to consume working memory resources and decrease task performance – the mindfulness group’s accepting perspective on their present-moment experience precluded the need for thought suppression and enabled participants to more efficiently refocus their attention on their current task.
These findings are informative in several ways. First, acute stress can decrease cognitive performance by constraining working memory. Stress can decrement how one performs at work or at school by inducing off-tasking thinking and disrupting the functioning of the working memory system. Second, brief mindfulness meditation practice can benefit working memory under the right conditions (i.e., during periods of acute stress). That is, mindfulness meditation might buffer or protect working memory from decrements due to stress. Third, these findings may be useful for anyone needing optimal working memory performance during periods of stress or off-task, ruminative thinking. So, consider meditating before your next exam, public talk, or stressful event!
To listen to a recorded mindfulness meditation similar to the instructions given in this study, you can view this example by Dr. William Brendel.
Featured Image: Flickr. Accessed 11/26/2018. https://www.flickr.com/photos/oddsock/3705388300