Cognitive task performance under (combined) conditions of a metabolic and sensory stressor

Effects of stressors on cognitive task performance have primarily been studied in isolation, and little is known about the combined effects of two or more stressors. This study examined how a metabolic stressor (skipping breakfast) and a sensory stressor (noise) affect cognitive task performance in isolation and combined. In addition to performance, we collected physiological and subjective data to get insight in the underlying mechanisms. Twenty participants came to the lab twice, once after skipping breakfast, and once after a standardized breakfast. They performed runs of the 2-back task and the International Shopping List Task, which were alternately presented with and without noise. During the 2-back task, electrocardiography (ECG), electrodermal activity (EDA), and electroencephalography (EEG) were recorded. Subjective ratings on effort and stress were also collected. No interaction effects between the two stressors on cognitive performance were found. Skipping breakfast did not cause hypoglycemia, but resulted in subjective discomfort and a lower state of arousal (as indicated by lower heart rate and EDA). These may underly the trend for more missed responses on the 2-back task after breakfast skipping. Noise appeared to generate arousal and increased attention (reflected in higher EDA and P300) in accordance with higher experienced load and stress. This is consistent with less missed 2-back responses in noise conditions. The results indicate that individuals spent extra effort to maintain task performance in the presence of noise. We propose to use a model that, besides additional effort, takes the effect of stressors on performance into account.