This thesis was carried out with two overall aims. The first was to test a possible interaction between cumulative stress and age on attentional processing. The second was to investigate the validity of a new theory of stress - the generalised unsafety theory of stress (GUTS; Brosschot, et al., 2016). Over the course of this project, 1074 individuals took part in four experiments to help address these aims.
Previous work has reported an interaction effect where older high stress participants perform worse than older low stress participants and worse than younger high or low stress participants. This interaction, reported for various cognitive tasks such as inhibition and working memory, has not yet been tested on attention. In chapters 2 and 3, we therefore expanded on previous work by measuring attentional performance (using the attentional blink task) and life time exposure to stress using self-report measures. We report mixed evidence for the stress/age interaction effect on attention. We suggest two reasons for the mixed results. The first being the difference in task design deployed between chapters leading to compensatory strategies reducing the effect of stress. The second is that increased age is largely associated with worse attentional performance in rapid attentional tasks such as the attentional blink task and so little scope is left to find the subtler effects of stress and this is linked to task load. Previous work also reported a stress/age interaction effect for resting state Delta power as measured by electroencephalogram. We do not report an increase in delta power for older, high stress participants as predicted or an association between delta power and task performance.
Our other main aim was based on the proposition that the current understanding of stress fails to provide an explanation for the maintenance of chronic stress. GUTS attempts to address this suggesting a perception of generalised unsafety (GU) is the mechanism for chronic stress maintenance and that when important life domains are compromised they contribute to GU perception. We tested two of these domains: the social network and the body domain, in chapters 4 and 5. We measured participants self-report loneliness, social fear, as well as perceived social support and self-esteem for the social network domain. We measured height, weight, BMI and overall physical activity for the body domain and used measured perceived stress as a proxy for GU. We found strong self-report evidence for the social network domain but not the body domain. However, we found no behavioural evidence for GUTS when using a valence discrimination task. We suggested this could be due to the problems of trying to operationalise GU. We also suggested GUTS might predict the perception of stress but not the behaviour associated with stress
