The impact of acute stress on cognitive functioning: a matter of cognitive demands?

Introduction: There is a controversy in the literature whether stress and related cortisol responses are beneficial or impairing for cognitive functioning. Conflicting results might be due to individual differences in stress reactivity and cognitive load of the applied tasks.Methods: N = 48 participants underwent the Socially Evaluated Cold Pressor Test and were confronted with the Frankfurter Aufmerksamkeits-Inventar-2 (FAIR-2) which is a low-load attention task and two subscales of the Intelligenz-Struktur-Test 2000 R (I-S-T 2000R) as a high-load reasoning task before and after the stressor. Participants were post hoc divided into high (stress induced cortisol increase of ≥1.5 nmol/l) vs. low-cortisol responders.Results: Cortisol responders showed an increased attentional performance in the post-stress condition (η2 > .14). However, there were neither stress or responder main effects nor an interaction effect on reasoning abilities.Conclusions: Results of the present study show that stress related changes in cognitive performance are due to individual differences in cortisol response and the cognitive load of the performed task. Future studies will show if these results are also valid for alternative cognitive tasks and if they can be replicated in female participants.