Adapting to the heat of the moment: A mobile experience sampling study on the dynamics of heat stress, appraisals, affect, and behaviour

Among the pressing challenges of climate adaptation is understanding and addressing perceptions and behaviour related to heat stress. Protective behaviour theories suggest that exposure to heat shapes perceptions, which can influence behaviour and, in turn, lead to changes in heat-related situational characteristics (e.g., moving to a cooler place). This mobile experience sampling study aims to identify the dynamic interplay between situational variations in exogenous heat stress, appraisals, affect, and behaviour. Firstly, we hypothesised that people adjust their threat appraisal to situational heat exposure, warnings, and protective activity and place characteristics (sensitivity hypothesis). Secondly, we expected that increased negative affect, threat appraisal, and coping appraisal precede protective behavioural changes (motivational hypothesis). Additionally, we explored whether reappraisals and affective alterations follow behavioural change (reappraisal hypothesis). By integrating meteorological and intensive longitudinal survey data, we collected a final sample of 4,387 observations from 134 participants. We used dynamic multilevel models on determinants of within-person changes in appraisal and behavioural characteristics. The results largely support our sensitivity hypothesis, as changes in threat appraisal are associated with situational heat stress, warnings, and protective characteristics. Whereas we found no evidence that appraisals or affect had a motivating effect preceding behavioural change, people reappraised temperatures as less threatening, less negative, and perceived themselves as better able to adjust after making protective behavioural changes. These findings suggest that situational factors are essential for explaining threat appraisal and thus underline the importance of longitudinal monitoring in research and heat action plans. While our findings do not support the notion that appraisals and affect motivate short-term heat-protective behavioural changes, we discuss the relevance of context-sensitive and flexible capacity-building, which can be influenced, for example, by warnings and urban planning measures. • People adjust situational threat appraisal to exogenous heat stress and context factors • No effect of appraised threats, coping options and affect on following behavioural changes • Receiving warnings precedes changes to less physically intensive activity • Reappraisals and improved affect about temperatures follow protective behavioural changes