Perceived social isolation and cognition

Abstract

Social species, from Drosophila melanogaster to Homo sapiens, fare poorly when isolated. Homo sapiens, an irrepressibly meaning-making species, are, in normal circumstances, dramatically affected by perceived social isolation. Research indicates that perceived social isolation (i.e. loneliness) is a risk factor for, and may contribute to, poorer overall cognitive performance, faster cognitive decline, poorer executive functioning, increased negativity and depressive cognition, heightened sensitivity to social threats, a confirmatory bias in social cognition that is self-protective and paradoxically self-defeating, heightened anthropomorphism and contagion that threatens social cohesion. These differences in attention and cognition impact on emotions, decisions, behaviors and interpersonal interactions that can contribute to the association between loneliness and cognitive decline and between loneliness and morbidity more generally.

Figure 1

Differential gene expression in individuals high versus low in loneliness. Genome-wide transcriptional profiles were assessed in peripheral blood leukocyte RNA samples collected from individuals in the top and bottom 15% of the distribution of subjective social isolation. Analysis by Affymetrix U133A high-density oligonucleotide arrays identified 209 transcripts showing >30% difference in mean expression levels across groups (green = over-expression in high-lonely, red = under-expression). High subjective social isolation is associated with a statistically significant net reduction in the number of expressed genes (131 down-regulated versus 78 up-regulated, p value by exact binomial test). (From Cole, Hawkley, Arevalo, Sung, Rose, & Cacioppo, 2007 .)

Figure 2

A cluster of voxels centered in the ventral striatum, but extending to the amygdala and portions of the anterior thalamus, showed an inverse relationship between loneliness and activation in the pleasant social–pleasant nonsocial contrast. The scatterplots demonstrate the association between loneliness and activity in this cluster in response to pleasant social pictures [r(21) = _.46, p < .05], and in response to pleasant nonsocial pictures [r(21) = .69, p < .001]. Estimated impulse response functions and mean percent signal change AUC for participants lower and higher in loneliness (estimates at 1 SD above and below the mean UCLA score in our sample are presented) show a crossover interaction for the relationship between loneliness and brain responses to pleasant social and pleasant nonsocial stimuli, such that nonlonely participants exhibit greater activation to pleasant pictures that contain social content and lonely participants exhibit greater activation to pleasant nonsocial pictures. (From Cacioppo, J. T., Norris, C. J., Decety, J., Monteleone, G., & Nusbaum, H. (2009). In the eye of the beholder: Individual differences in perceived social isolation predict regional brain activation to social stimuli. Journal of Cognitive Neuroscience, 2009 .)

Figure 3

The effects of loneliness on human cognition.