Loneliness and Resting Parasympathetic Activity Interact to Influence Approach Motivations

Loneliness, or perceived social isolation, increases motivation to approach and reaffiliate while simultaneously enhancing sensitivity to potential threats, allowing individuals to avoid further social threats. Some individuals successfully leverage these competing motivations to reduce feelings of loneliness. However, others further withdraw, perpetuating a harmful cycle of loneliness. What drives this variability in responses to loneliness is still not well understood. Prior research found that resting parasympathetic nervous system (PNS) activity, linked to increased regulatory capacity and more flexible adaptation, moderates responses to loneliness. Individuals with higher resting PNS activity and higher levels of loneliness demonstrate enhanced approach of both positive and negative information. Here, we aimed to replicate and expand on this research, examining whether this effect is more pronounced for social information. 107 participants (ages 18 to 56 years) completed an approach-avoidance task in which they made decisions about whether to approach or avoid positive and negative social or non-social images. For individuals with higher resting PNS activity, loneliness was associated with reduced approach of negative information, but no differences in approach of positive information. These effects were comparable for social and non-social stimuli. Our findings suggest lonely individuals with higher resting PNS activity may be better able to flexibly leverage shifts in approach and avoidance motivations in a context-dependent manner, contributing to the field’s understanding of how loneliness shapes motivated behaviors as a function of environmental context, particularly the social nature of incoming valenced information.