Individual Differences in Environmental Sensitivity

A fundamental trait found in most organisms is the ability to register, process, and respond to external factors. Although such environmental sensitivity is critical for adapting successfully to contextual conditions, individuals tend to differ in their sensitivity to the environment, with some more sensitive than others. Such differences in environmental sensitivity can be seen across many species, including humans. Although the notion of variability in environmental sensitivity is reflected indirectly in many traditional concepts of human psychology, several new frameworks address individual differences in environmental sensitivity more directly and from a perspective of developmental and evolutionary theory. In this article, I integrate these perspectives into a broad meta-framework before proposing ideas for research on individual differences in environmental sensitivity. I also emphasize that inter-individual variability in environmental sensitivity be considered in both theoretical and applied work. KEYWORDS—environmental sensitivity; developmental plasticity; diathesis-stress; vulnerability; resilience; differential susceptibility; vantage sensitivity Human development is fundamentally contextual. Without the specific and active support of a nurturing environment, no child would thrive or even survive. Given this dependence on external environmental resources, it is not surprising that humans register, process, and respond to many different aspects of their social and physical environment. However, individuals differ substantially in such sensitivity and responsivity, with some being more and others less responsive to the same environmental conditions. In this article, I look at individual differences in environmental sensitivity, drawing from several theoretical perspectives and emerging empirical evidence. Rather than discussing in detail conceptual differences between the various frameworks, I present an integrated view across concepts and perspectives. Finally, I propose research on individual differences in environmental sensitivity and suggest that we consider inter-individual variability in environmental sensitivity in both theoretical and applied work. VARIABILITY IN ENVIRONMENTAL SENSITIVITY Individual differences in the behavioral response to environmental factors can be seen across many species from pumpkinseed fish, zebra finches, mice, and nonhuman primates to humans (for review, see 1). The pattern that seems to emerge consistently is that some of the members of each of these species tend to be bold, aggressive, and impulsive when approaching new or threatening situations, whereas others appear to avoid such situations, behaving less aggressively and more cautiously and fearfully. These two prototypical behavioral types have been described as hawks and doves, reflecting two different behavioral strategies—proactive versus reactive coping (2)—that evolved over time, each characterized by specific advantages and disadvantages for health and reproductive fitness (3). Similar behavioral differences have been described in humans in many psychological frameworks, including extraand introversion, behavioral activation and inhibition, high and low reactive temperament, physiological stress reactivity, sensory sensitivity, resilience and vulnerability, reaction norms, and developmental plasticity (4–6). Although these established psychological concepts differ from one another, they all seem to describe how people vary in their response to contextual factors, with some more affected than others, manifested in qualitatively different psychological or behavioral response patterns. The notion that individuals differ in how they perceive and process environmental Michael Pluess, Queen Mary University of London. I express my gratitude to Judy Stamps, Elaine Aron, Bruce Ellis, and Jay Belsky for their comments and discussion of an earlier version of this article. Correspondence concerning this article should be addressed to Michael Pluess, Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom; e-mail: [email protected].