Phd in PHD PROGRAM IN BEHAVIORAL NEUROSCIENCE

Thesis title: Loneliness effects on social attention and affective processes

Loneliness, an aversive state often associated with depression or anxiety, differs from being physically alone and is characterized by the perception of being socially isolated and dissatisfied with current social relationships. It can range from transient sensations to chronic conditions, with the latter linked to various mental and physical health problems including anxiety or depression, cardiometabolic disease and increased mortality rates. Theoretical models of loneliness propose that lonely individuals are prone to negative thinking, expect rejection, and perceive their social environment as threatening. Evidence from studies using emotional stimuli, in particular emotional faces, have showed that socially excluded participants are more likely to give priority to social relevant positive stimuli. Studies have also evidenced that socially excluded individuals tend to avoid negative relevant social stimuli, in line with the hypothesis that social exclusion motivates toward affiliative related cues and away from negative social stimuli. The present research aims to comprehensively explore the impact of loneliness on memory for faces, orienting attention to social cues, selective attention to faces, and inhibition for social stimuli. The first study aimed to investigate whether loneliness and social contacts modulated the Own Age Memory Bias, i.e., the enhanced recognition for faces pertaining to the individuals own age group. Results indicated that individuals reporting lower levels of loneliness were more likely to exhibit an Own Age Bias for novel signs of affiliation, specifically novel happy faces. Conversely, this bias was not observed in individuals with higher levels of loneliness. The second study examined the modulation effect of loneliness on attentional shift towards emotional faces. Although gaze cueing effects were observed, no group differences between lonely and non-lonely participants emerged. The third study aimed to assess the modulation effect of loneliness on selective attention for emotional faces. Results showed interference from emotional distractors when the valence of targets word did not match the valence of the distractor’s facial expression, but no effect of loneliness. The forth study explored the impact of loneliness on later processes of cognition, specifically whether loneliness influenced response inhibition to emotional stimuli. Result evidenced a modulation effect of emotion in response inhibition; however, this was independent of loneliness. Understanding the effects of loneliness on different aspects of social cognition is crucial, but it has become more urgent recently as especially young individuals have suffered from the lack of social contacts with their peers during the Covid-19 lockdown. Future research on the effects of loneliness on social cognition may be beneficial to comprehend if the mechanisms contributing to prolonged loneliness involve reduced bias towards negative stimuli or hypervigilance towards social threat signals.