Naltrexone Alters Responses to Social and Physical Warmth: Implications for Social Bonding

Tristen K. Inagaki; Laura I. Hazlett; Carmen Andreescu


Soc Cogn Affect Neurosci. 2019;14(5):471-479. 

In This Article

Social–Physical Warmth

Connecting with others is often described as a heart-warming or warm experience. More than metaphor, physical warmth, and the thermoregulatory pathways that keep individuals at an optimally warm core body temperature, may also contribute to experiences of social warmth, the experience of feeling loved by, cared for and connected to other people (Panksepp, 1998; Inagaki et al., 2016b). In particular, we have proposed that humans have an innate system that both supports social warmth and concurrently maintains core temperature for survival purposes (Inagaki et al., 2016b). The association between social and physical warmth may have then been strengthened by our very first social encounter: that between infant and caregiver. Warmth may have simultaneously signaled the proximity of a caregiver (physical warmth) and of potential care or connection (social warmth) such that later in life there may be a bidirectional relationship where activating either physical or social warmth might similarly activate the other.

In support of this hypothesis, cutaneous warmth has been shown to affect social warmth and the reverse (though results are not uniform; Lynott et al., 2014). For example, holding a warm object (vs room temperature object) led to increases in affiliative feelings (IJzerman and Semin, 2009; Fay and Maner, 2012). In the other direction, experimentally increasing feelings of social connection led to increases in feelings of warmth (Inagaki and Eisenberger, 2013), whereas experimentally decreasing feelings of social connection led to decreases in perceptions of warmth (Zhong and Leonardelli, 2008).

More direct evidence for shared mechanisms comes from neuroimaging work in humans. Neural activity to a socially warm experience shared overlapping neural activity with physical warmth but not another pleasant task (Inagaki and Eisenberger, 2013). Specifically, activity in the VS and MI, regions known to activate to warm thermal stimuli (e.g. Rolls et al., 2008) and, separately, to close social connections (Bartels and Zeki, 2004; Aron et al., 2005; Acevedo et al., 2012; Inagaki and Eisenberger, 2013; Atzil et al., 2017), showed similar responses to both kinds of experiences. Thus, it is possible that these regions contribute to the convergence of the subjective experiences of warmth and social connection.