Under Pressure: The Effects of Stress and Cognitive Load on Interrogative Suggestibility

High-stakes situations, like police interrogations, can impair critical thinking due to stress and cognitive demands, making individuals more susceptible to suggestion. While much research focuses on children, young adults are also at risk for interrogative suggestibility, which can have serious legal consequences. This study experimentally manipulated stress and cognitive load to test whether both factors increase suggestibility in young adults, both independently and interactively, with the highest suggestibility among those experiencing both greater stress and cognitive demands. This was evaluated by examining both condition effects and self-reports of stress and cognitive load. College students (N = 230), aged 18 to 26, were randomly assigned to one of six experimental conditions in a 3 (stress induction via interpersonal and environmental factors: low, neutral, high) x 2 (cognitive load: inherent, increased) between-subjects design. Multiple self-report measures assessed perceived stress and mental effort, and the Gudjonsson Suggestibility Scale (GSS) "yield" scores served as the primary measure of suggestibility. As hypothesized, participants in the increased load condition exhibited higher yield suggestibility scores than those in the inherent load condition. However, the varying levels of induced stress did not significantly influence suggestibility, nor was there a significant interaction between stress and cognitive load. These findings highlight the distinct impact of cognitive load on increasing vulnerability to suggestion in young adults, independent of the stress induced in the study. Results highlight the importance of considering cognitive demands during questioning and suggest that taxing cognitive resources may be a key factor influencing suggestibility.