Acute stress and human spatial working memory strategy use

Figures & data

Figure 1. Timeline of study procedures. HR: heart rate recording interval; VAS: visual analogue scale subjective stress rating; S: saliva sample; TSST: Trier Social Stress Test; Control: control tasks; CANTAB: spatial working memory subtest of the Cambridge Neuropsychological Test Automated Battery.

Study procedure timeline. The study began with informed consent, a demographic questionnaire, and paper mazes that took a total of thirty minutes. Next there was a five-minute heart rate measurement and three minutes of subjective stress and saliva collections. The TSST or control tasks were then performed for fifteen minutes. Heart rate was recorded for five minutes during the speech preparation period and ten minutes during performance of the speech and math tasks. A second subjective stress rating was then collected for one minute and was followed by the CANTAB spatial working memory task which lasted ten minutes. The study concluded with a third subjective stress rating and a second saliva collection which took a total of three minutes.

Figure 2. (a) Untransformed mean visual analogue scale (VAS) subjective stress ratings made at baseline (VAS1), immediately following the Trier Social Stress Test or control tasks (VAS2), and immediately following the CANTAB spatial working memory task (VAS3). (b) Untransformed mean salivary cortisol levels at baseline (S1) and immediately following the CANTAB spatial working memory task (S2). All participant data points are also plotted. Control: control group participants; Stress: stress group participants.

Plots of mean and individual participant untransformed subjective stress ratings and salivary cortisol levels. Stress participants’ subjective stress ratings were higher than controls only immediately after the Trier Social Stress Test. Stress participants’ salivary cortisol levels were higher than controls only immediately following completion of the CANTAB spatial working memory task.

Figure 3. (a) Mean spatial working memory between search errors. (b) Mean first box-based strategy proportions. (c) Mean sequence-based strategy proportions. All participant data points are also plotted. Control: control group participants; Stress: stress group participants.

Three bar charts showing mean and individual participant values for spatial working memory between search errors, first box-based strategy proportions, and sequence-based strategy proportions. There were no significant group differences in between search errors or search strategy proportions.

Table 1. Pearson product-moment correlations between stress group participants’ subjective stress responses, cortisol stress responses, between search errors, first box-based strategy proportions, and sequence-based strategy proportions.

	VAS3 - VAS1^a	S2 - S1^a
Between search errors	0.04	−0.08
First box-based strategy proportion	0.06	−0.13
Sequence-based strategy proportion	0.10	−0.09

VAS: Visual Analogue Scale rating of subjective stress; S: salivary cortisol.

^aAll ps > 0.050.

Data availability statement

Data are available from the corresponding author upon request.