Physiological stress responses to digital single- and multitasking demands in younger and older adults

Differences in multitasking (MT) performance have been found across the lifespan. Little is known about physiological stress responses to MT demands in older people. In our study, 106 younger (22.8 ± 3.9 years, 75.5 % female) and 113 older adults (70.9 ± 5.1 years, 70.8 % female) participated and were assigned to either a single-tasking (ST) or an MT condition. Physiological stress responses of the Autonomic Nervous System (ANS), and the hypothalamic-pituitary adrenal (HPA) axis were assessed. Task 1 was a sentence verification task, which was interrupted by push notifications (task 2) in the MT condition. Participants answered questions that assessed their comprehension of the notification content afterwards. Performance was lower in the MT condition in the older participants in task 1. All participants perceived stress during both tasks. Autonomic responses (i.e., for heart rate) were found for the MT condition in the older participants. No differences in physiological stress responses were found for the further autonomic measures. Cortisol levels decreased throughout the session for all participants. Our results confirm that MT performance decreases in older age. This may be associated with stronger ANS responses during MT in older than in younger people. Our findings partially support the specificity hypothesis, i.e., that cognitive stressors specifically initiate responses of the ANS, but no responses of the HPA axis. More research with more demanding tasks and the inclusion of further factors such as experience with MT and educational level is needed.