Attention to Fear-Relevant Stimuli by Adults and Young Children

Snakes are among the most common targets of fears and phobias. In visual detection tasks, adults detect their presence more rapidly than the presence of other kinds of visual stimuli. We report evidence that very young children share this attentional bias. In three experiments, preschool children and adults were asked to find a single target picture among an array of eight distractors. Both the children and the adults detected snakes more rapidly than three types of nonthreatening stimuli (flowers, frogs, and caterpillars). These results provide the first evidence of enhanced visual detection of evolutionarily relevant threat stimuli in young children. Many people—perhaps most—have had the experience of suddenly feeling frightened by the presence of a snake basking in the sun on the path ahead or nearly hidden in the grass alongside. Such fearful reactions occur relatively frequently, as most people have a negative orientation to snakes, and snakes constitute one of the most common objects of intense fears and phobias (Fredrikson, Annas, Rischer, & Wik, 1996; King, 1997). Fearful reactions to snakes have also been observed in a variety of nonhuman primates (e.g., Cook & Mineka, 1989; Yerkes, 1943). The prevalence of snake fear has led some theorists (e.g., Öhman &Mineka, 2001; Seligman, 1970) to consider it to be an example of prepared learning, the idea being that humans have an evolved predisposition to associate snakes with fear. According to this view, poisonous snakes (and spiders) constituted a recurrent threat to survival throughout most of mammalian evolution, so animals that quickly learned to avoid them were more likely to survive, reproduce, and pass on their genes. Consequently, a tendency to readily learn to fear snakes evolved in humans and other mammals. Empirical support for prepared learning of snake fear in humans has come from research with adults showing superior conditioning of fear-relevant responses (e.g., heart rate acceleration) to snake stimuli (see Öhman & Mineka, 2001, for a review). Evidence for prepared learning in nonhuman primates has come from research by Mineka and her colleagues (Cook & Mineka, 1989; Öhman & Mineka, 2001) showing that monkeys very rapidly learn to fear snakes simply from seeing another monkey react fearfully to the presence of a snake. In a related vein, Öhman (1993; Öhman & Mineka, 2001) proposed the existence of an evolved fear module—a neural system that is selectively sensitive to evolutionarily relevant threat stimuli. The evolutionary claim is that individuals who more rapidly detected the stimulus attributes signifying the presence of a poisonous snake or a spider would have been more likely to escape the danger and hence to survive and reproduce. As a consequence, a mechanism supporting the rapid detection of this type of dangerous stimulus evolved. The claim for the existence of a bias toward the rapid detection of evolutionarily relevant threat stimuli has received empirical support from visual search studies showing faster detection of fear-relevant than fear-irrelevant stimuli. Öhman, Flykt, and Esteves (2001) presented participants with matrices consisting of pictures of snakes (fear relevant) and flowers (fear irrelevant). One of the two types of stimuli was designated the target, and each matrix included either a single target or no target. Participants had to decide as quickly as possible whether or not the target was present in each trial. They reliably detected the presence of a snake target among flowers more quickly than a flower target among snakes. The same pattern of results was obtained for spiders versus mushrooms. Moreover, participants who reported being afraid of snakes found snake targets even faster than nonfearful individuals did. The basic finding reported by Öhman et al. (2001)—more rapid detection of snakes and spiders than of non-threat-relevant stimuli—has been replicated by several other investigators (e.g., Lipp, Derakshan, Waters, & Logies, 2004; Tipples, Young, Address correspondence to Vanessa LoBue, University of Virginia, PO Box 400400, Charlottesville, VA 22904, e-mail: vl8m@virginia. edu. PSYCHOLOGICAL SCIENCE 284 Volume 19—Number 3 Copyright r 2008 Association for Psychological Science Quinlan, Broks, & Ellis, 2002). However, some of the results of these studies are inconsistent with the conclusions reached by Öhman et al. In some cases, superior detection was also found for non-threat-relevant animals (e.g., bears, dogs, and kittens; Tipples et al., 2002). In addition, there are reports of superior detection of modern threatening stimuli (e.g., syringes, guns, and knives; Blanchette, 2006; Brosch & Sharma, 2005). Furthermore, in some of these studies, results varied with the number of distractors, contrary to the analysis offered by Öhman et al. All of these visual search results and claims are based on adult participants, who presumably have extensive knowledge about snakes and various kinds and degrees of experience with them (Rachman, 2002). However, if humans have an evolved ability to detect threat-relevant stimuli exceptionally quickly, as proposed by Öhman (Öhman et al., 2001; Öhman & Mineka, 2001), the tendencymight be observable in individuals with relatively little or no experience with such stimuli. Thus, the primary goal of the research reported herewas to take a developmental approach to the topic of threat detection, examining the visual detection of evolutionarily relevant threat stimuli—snakes—by very young children. A second goal was to expand the range of comparison stimuli used to examine the detection of snakes. All of the previous research compared detection of snakes with detection of one or two nonthreat stimuli (typically flowers or plants). In contrast, we compared the detection of snakes with the detection of a variety of other types of stimuli, including, most notably, other animals. These comparisons provide particularly strong tests of the hypothesized advantage for the detection of threat-relevant stimuli.