Loneliness and Health: Physiological and Cognitive Mechanisms in Adulthood and Childhood

Abstract

This thesis outlines a series of six studies that examine the potential cognitive and physiological mechanisms that underpin the association between loneliness and health. The current theoretical model (Cacioppo & Hawkley, 2009) proposes that loneliness is linked to poor health through hypervigilance to social threat (HSTH), resulting in increased activation of the hypothalamic-pituitary-adrenal (HPA) axis. The first two studies address gaps in the adult literature for loneliness and health and examine HSTH and the HPA axis stress response in real life social contexts: public speaking and meeting strangers.
In adulthood, long term loneliness has been linked to poor health (Shioitz-Ezra & Ayalon, 2010); within childhood literature loneliness and health has only been examined in cross-sectional studies (Mahon & Yarcheski, 2003; Mahon et al., 1993). Thus, the fourth and fifth studies use a longitudinal design to examine loneliness and health in childhood. Cacioppo and Hawkley (2009) also propose that the HSTH in lonely people results in cognitive biases in processing of social information, which affect behavioural responses in social situations. Although cognitive biases have been examined in adulthood, this is yet to be examined in children, so the sixth study addresses this gap in the literature. The final study examines relationships between loneliness and perception of social threat in a real life social context for children: the transition from primary to secondary school.
Findings demonstrate, similar to adult literature, that long-term loneliness in childhood is linked to poor health. Further, evidence for HSTH in lonely adults and children in real life social contexts was demonstrated, offering ecological validity for the current theoretical model (Cacioppo & Hawkley, 2009). The results also implicate chronic stress and a lack of cortisol flexibility as functional mechanisms linking loneliness to poor health. Unlike research with adults, memory biases for social information were not found in lonely children, indicating that lonely children may process social information different to lonely adults. Lonely children also found it harder to ignore irrelevant distractors in cognitive tasks than non-lonely children, when the distracting information involved speech, but not when it was a visual distraction, indicating that speech information is processed differently than other distractors in lonely children.
It is argued that Cacioppo and Hawkley’s (2009) model should be re-examined in light of the findings. Key areas for examination of the current theoretical model (Cacioppo & Hawkley, 2009) are highlighted and discussed: the adoption of chronic stress as a functional mechanism linking loneliness to poor health, investigation of mechanisms that result in a reduction of loneliness levels, and an introduction of a developmental perspective to understanding processes involved in the maintenance of loneliness.