Loneliness in the Brain: Distinguishing Between Hypersensitivity and Hyperalertness

Introduction: Loneliness has emerged as a pressing public health issue, necessitating greater understanding of its mechanisms to devise effective treatments. While the link between loneliness and biased social cognition is a commonly proposed, the precise nature of this relationship remains unclear. This study aims to investigate the cognitive processes underlying loneliness, specifically distinguishing between hypersensitivity (heightened initial response) and hyperalertness (slow habituation) to social stimuli in lonely individuals.Methods: In Study 1, 36 participants were tested to identify the relevant EEG channels and time windows that show differential processing of angry vs happy faces and first vs later exposure in a roving oddball paradigm. Study 2 will compare these face processing effects in lonely and non-lonely participants. We aim to recruit a sample of 50 lonely and 50 non-lonely participants, who will be identified by their responses on a standardised loneliness questionnaire with population norms.Results: In Study 1, a greater response to angry compared to happy facial expressions was observed between 120-170ms over posterior and central channels, and between 360 and 470ms over right posterior channels. A greater response to the initial compared to the fifth presentation of an emotional face was found between 480 and 600ms over right posterior and central channels. These findings align with previous research on emotion and novelty processing in similar experiments.For Study 2, we anticipate observing higher response amplitudes when comparing angry expressions to happy expressions in lonely participants, indicating hypersensitivity. Furthermore, we expect to see greater amplitudes when comparing early presentations to late presentations of angry faces in lonely individuals, indicating increased alertness.Discussion: to be added at Stage 2