From the perspective of evolutionary psychology, anxiety is an adaptive mechanism. If you are a zebra at a watering hole and the grass moves, you had better run like hell. Ninety-nine times out of hundred it will just be the wind; the one time it is a lion and you don’t run you will have lost more than your reproductive capacity…
From
Irrational Emotions or Emotional Wisdom?
The Evolutionary Psychology of Emotions and Behavior
Martie G. Haselton
UCLA, Center for Behavior Evolution and Culture
&
Timothy Ketelaar
New Mexico State University, Department of Psychology
As we have already hinted, perhaps nowhere does there exist better evidence for the domain-specificity of emotion than in the domain of fear. Modern environments possess an abundance of lethal threats that hardly evoke a moment’s notice. Humans routinely operate speeding automobiles, work around sources of electrical hazard, and expose themselves to carcinogenic agents without breaking a sweat. Yet, a single harmless stinging insect can bring about behavioral changes that are detectable for several city blocks. Why do humans appear to lack fear of objects that can kill (automobiles and electrical outlets) and yet display an almost debilitating fear of objects that present only a small threat (spiders and snakes)? In this section, we illustrate how an adaptationist view on the functional-specificity of emotions allows us to make sense of this otherwise puzzling array of fear responses.
Evolutionary psychologists argue that the non-random distribution of fear stimuli is a legacy of the evolutionary past. The absence of fear responses to evolutionarily novel sources of danger (automobiles, electrical outlets, etc.), for example, suggests that emotional responses are not simply the product of rational deliberation. Instead, human fears are the result of domain-specific mechanisms that correspond to ancient sources of harm such as dangerous animals, bodily insults, heights, social evaluation, and the risk of social exclusion (Costello, 1982; Marks & Nesse, 1994; Nesse, 1990; Ohman & Mineka, 2001; Seligman, 1971). Snake fear is perhaps the best researched example. Although snakes do not pose much of a risk in modern environments, snakes and humans have coexisted for millennia and snake bites can be lethal. In the laboratory, researchers can condition people to fear snakes and snake-like stimuli using mild electrical shocks. By contrast, it is difficult to condition fear to other stimuli, even those with strong semantic associations with shock (e.g., damaged electrical outlets; see Ohman & Mineka, 2001 for a review). Unlike responses to evolutionarily novel sources of harm, biologically prepared fear responses (snakes, spiders, etc.) are notoriously difficult to extinguish (see Mineka, 1992; Cook & Mineka, 1990; Nesse, 1990; Marks & Nesse, 1994; Seligman, 1971 for reviews).
One of the curiosities of evolved fear responses is that they often appear over-responsive (Nesse, 1990, 2005). For example, prey animals express startle and flight responses at rates that suggest that they overestimate risk (Bouskila & Blumstein, 1992), and the human tendency to acquire and retain snake fears on the basis of slim evidence can also be conceived of as a bias (Haselton & Nettle, in press). Rather than indicating irrationality, this hyper-sensitivity to particular environmental cues may be due to error management (Haselton & Buss, 2000; Haselton & Nettle, in press). For example, when the costs of expressing a defensive reaction are small (e.g., a few calories spent fleeing), whereas the consequences of failing to do so can be deadly (failing to evade a predator), it pays to err on the side of making false positive errors rather than false negative errors, even if this increases overall error rates (Bouskila & Blumstein, 1992; Nesse, 1990; Haselton & Nettle, 2005). In sum, adaptive over-responsiveness in our emotional reactions may sometimes lead to the mistaken impression that defensive emotions (fear, anxiety, and aggression) are not well designed.
