Trends in Cognitive Sciences
ReviewPerceived social isolation and cognition
Introduction
The health, life and genetic legacy of members of social species are threatened when they find themselves on the social perimeter. Social isolation decreases lifespan in the fruit fly [1]; promotes obesity and Type 2 diabetes in mice [2]; exacerbates infarct size and edema and decreases post-stroke survival rate following experimentally induced stroke in mice [3]; promotes activation of the sympatho-adrenomedullary response to an acute immobilization or cold stressor in rats [4]; delays the effects of exercise on adult neurogenesis in rats [5]; decreases open field activity, increases basal cortisol concentrations and decreases lymphocyte proliferation to mitogens in pigs [6]; increases the 24 h urinary catecholamines levels and evidence of oxidative stress in the aortic arch of rabbits [7]; and decreases the expression of genes regulating glucocorticoid response in the frontal cortex of piglets [8]. Humans, born to the longest period of abject dependency of any species and dependent on conspecifics across the lifespan to survive and prosper, do not fare well either, whether they live solitary lives or simply perceive that they live in relative isolation (Box 1).
Perceived social isolation, known more colloquially as loneliness, was characterized in early scientific investigations as ‘a chronic distress without redeeming features’ (p. 15) [9]. Recent research suggests that the social pain of loneliness evolved as a signal that one's connections to others are weakening and to motivate the repair and maintenance of connections to others that are needed for our health and well being and for the survival of our genes (Box 2) [10]. Experimental, cross-sectional and longitudinal studies are beginning to elucidate the various ways in which loneliness is related to, and in some cases affects, human information processing.
Section snippets
Cognitive capacities
Human social processes were once thought to have been incidental to learning and cognition, whereas the social complexities and demands of primate species are now thought to have contributed to the evolution of the neocortex and various aspects of human cognition. Consistent with this reasoning, human toddlers and chimpanzees have similar cognitive skills for engaging the physical world but toddlers have more sophisticated cognitive skills than chimpanzees for engaging the social world [11];
Executive functioning
Executive functioning includes the capacity to control one's attention, cognition, emotion and/or behavior to better meet social standards or personal goals, that is, to self-regulate. Early evidence from young adults who performed a dichotic listening task suggested that attentional regulation was poorer in lonely than nonlonely individuals [24]. Participants were asked to identify the consonant-vowel pair presented in the left or right ear. Typically, performance shows a right-ear advantage
Colorations of cognition
Experimental manipulations of loneliness not only impair executive functioning but also produce higher negative mood, anxiety, anger and depressive symptomatology [30]. An experience sampling study, in which participants were beeped randomly nine times per day for seven days, confirmed that the social interactions of lonely, in contrast to nonlonely, individuals were more negative and less satisfying and such interactions contributed subsequently to more negative moods and interactions [31].
Social cognition
The brains of lonely, in contrast to nonlonely, individuals are on high alert for social threats, so lonely individuals tend to view their social world as threatening and punitive (Box 3). Experimental manipulations of loneliness not only cause people to feel more anxious, fear negative evaluation and act more coldly toward others [30], but it also causes them to feel colder as assessed by ratings of room temperature [42]. Lonely individuals also tend to form more negative social impressions of
Contagion
Loneliness is typically investigated as an individual factor, but because perceived and objective isolation can be differentiated, loneliness can also vary within and across groups. Network linkage data from the population-based Framingham Heart Study were used to trace the topography of loneliness in social networks and the path through which loneliness spreads through these networks [52]. Results indicated that loneliness occurs in clusters within social networks, is disproportionately
Conclusion
Cognition has been regarded as a quintessential individual activity. Mental representations and processes were rendered testable in the dawn of the cognitive sciences by virtue of reverse engineering: mathematical and computer models were created that specified stimulus inputs, information processing operations that acted on and transformed these inputs to produce and change representational structures, and information processing operations that led to observable responses. Computers today are
Disclosure statement
This research was supported by the National Institute of Aging Program Project Grant No. PO1 AG18911 & RO1 AG034052-01 and by a grant from the John Templeton Foundation. These funding sources had no role or influence in the preparation of this review.
References (78)
Immobilization and cold stress affect sympatho-adrenomedullary system and pituitary-adrenocortical axis of rats exposed to long-term isolation and crowding
Physiol. Behav.
(2004)Consequences of repeated early isolation in domestic piglets (Sus scrofa) on their behavioural, neuroendocrine, and immunological responses
Brain Behav. Immun.
(2004)Effects of early weaning and social isolation on the expression of glucocorticoid and mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase 1 and 2 mRNAs in the frontal cortex and hippocampus of piglets
Brain Res.
(2006)Double dissociation of social and environmental stimulation on spatial learning and reversal learning in rats
Behav. Brain Res.
(2004)Behavioral, neurochemical and endocrinological characterization of the early social isolation syndrome
Neuroscience
(2000)Decreased dendritic spine density on prefrontal cortical and hippocampal pyramidal neurons in postweaning social isolation rats
Brain Res.
(2003)Brain-derived neurotrophic factor mRNA downregulation produced by social isolation is blocked by intrahippocampal interleukin-1 receptor antagonist
Neuroscience
(2003)Lonely traits and concomitant physiological processes: the MacArthur social neuroscience studies
Int. J. Psychophysiol.
(2000)Loneliness within a nomological net: An evolutionary perspective
J. Res. Pers.
(2006)- et al.
Unconscious affective processing and empathy: an investigation of subliminal priming on the detection of painful facial expressions
Pain
(2009)