Be(a)ware of spider! An attentional blink study on fear detection.

Abstract

We investigated whether detection of fearful stimuli is independent from attention by using an iconic version of the Attentional Blink Task in arachnophobic individuals. A colored animal icon (Target) and a black spider or butterfly icon (Probe) appeared in close temporal proximity within a stream of distractors, at one of 4 possible time lags. In one task, Probe detection was required; in another one, Target identification was also requested. In this case, competition for attentional resources produces the so-called AB effect, that is the decrease of Probe perception as a function of lag. During spider-Probe detection, arachnophobics showed a reduced AB effect with respect to the butterfly-Probe session. Their spider detection scores were also greater than ratings obtained by non-phobic controls with both Probe types. Thus, fear appears to enhance the probability of consciously perceiving the stimulus even when attention is engaged by a previous demanding event. One may assume that spider-Probe is scarcely attention demanding because detection of threat in arachnophobics is increased by rapid amygdala activation of visual areas and/or facilitated by a strong arousal-induced noradrenergic cortical input. Alternatively, an attention capturing mechanism involuntary triggered by the phobic meaning of the stimulus could be hypothesized.