Tracking fear in snake and spider fearful participants during visual search: A multi-response domain study

Abstract

In visual search tasks snake or spider fearful participants showed shorter reaction times (RTs) to respond to their feared animal (e.g., snake) than to the nonfeared animal (i.e., spider) (Öhman, Flykt, & Esteves, 2001). Here, we used this paradigm with heart rate (HR), RTs, and event-related potential (ERP) measures, to investigate the nature of the responses to the feared animal, a nonfeared (but fear-relevant) animal, and fear-irrelevant target stimuli with snake fearful, spider fearful, and nonfearful participants. Fearful participants showed shorter RTs and evoked larger amplitudes on a late positive potential (LPP; 500–700 ms) for their feared compared to the nonfeared and the fear-irrelevant targets. No relevant significant differences were found on early ERP components and HR measures. These findings do not support an involvement of early information processing in the detection of the feared animal in fearful participants, they favour instead a more elaborated analysis of these complex stimuli to achieve the detection.

Acknowledgments

This research was supported by the FNRS Grant No. 11-61659.00 provided by the Swiss National Science Foundation, a grant given to Klaus Scherer and Anders Flykt for the study of threat appraisal and its physiological correlates. The authors are grateful to Klaus Scherer for supporting this study, to Thomas Wherle for programming both the heart rate changes analysis program and also a program that transformed the matrix search arrays into nonfigurative pictures with the same colours and luminance as the original search arrays for the baseline in the event-related potential (ERP) experiment, to Lara Desire for recruiting the fearful subjects and assisting in both experiments, and to Didier Grandjean for assisting in the ERP experiment. We would like to thank Denis Brunet for his ERP analysis software: Cartool 3.1. Anders Flykt is now at the Mid Sweden University, Ostersund, Sweden, Roberto Caldara is currently supported by a post-doctoral fellowship provided by the Swiss National Science Foundation. We are grateful to Gillian Bruce for her comments on a previous version of the manuscript.