Contact Esther Brendel (e-mail: ebrendel@uni-mainz.de) Universität Mainz, Psychologisches Institut, 55099 Mainz, Germany Acknowledgements Funded by DFG-Sachbeihilfe HE 2122/6-1 „Kontaktzeitschätzung im Kontext“ We thank Bernhard Both, Oliver Daum, Lisa Kiltz, Malte Klüver, Benyne Palayoor Jos, Stephanie Preuß, Johannes Rau, Tobias Schneider, Maurizio Sicorello, Kristiane Usitzka, Romy Weiland, and Lisa Zschutschke for data collection, and Agnes Münch for assistance in programming. 36th European Conference on Visual Perception (ECVP), 25-29 August 2013, Bremen, Germany Emotional factors in time-to-contact estimation Esther Brendel, Heiko Hecht, Johannes Gutenberg-Universität Mainz References Brendel, E., DeLucia, P., Hecht, H., Stacy, R., & Larsen, J. (2012). Threatening pictures induce shortened time-to-contact estimates. Attention, Perception, & Psychophysics, 74(5), 979–987. DeLucia, P. R. (1991). Pictorial and motion-based information for depth perception. Journal of Experimental Psychology: Human Perception and Performance, 17(3), 738–748. Ferneyhough, E., Kim, M. K., Phelps, E. A., & Carrasco, M. (2013). Anxiety modulates the effects of emotion and attention on early vision. Cognition & Emotion, 27(1), 166–176. Vagnoni, E., Lourenco, S. F., & Longo, M. R. (2012). Threat modulates perception of looming visual stimuli. Current Biology, 22(19), R826. Lang, P. J., Bradley, M. M., & Cuthbert, B. N. (2005). International affective picture system (IAPS): Affective ratings of pictures and instruction manual. Technical Report A-6. University of Florida, Gainesville, FL. Hanoch, Y., & Vitouch, O. (2004). When less is more: Information, emotional arousal and the ecological reframing of the Yerkes-Dodson Law. Theory & Psychology, 14(4), 427–452. Method Measures  time-to-contact judgments of IAPS pictures (Lang et al., 2005)  picture ratings: self-assessment-manikins  skin conductance measurement (Exp. 2) Varied design (always fully crossed)  200 to 1000 ms visible approach  600 to 1200 ms time-to-contact after picture‘s disappearance  4 or 5 m/s approach velocity  2 picture sizes Stimulus categories Experiment 1: threatening versus pleasant Experiment 2:  threatening  pleasant  neutral  spiders (not from IAPS) Experiment 3:  neutral  flat color control  6 combinations of valence and arousal: Background Recently, the emotional content of a looming stimulus has been shown to affect time-to-contact estimation. Threatening pictures of attacks (Brendel et al. 2012) and of spiders and snakes (Vagnoni et al. 2012) are judged to arrive sooner compared to neutral pictures, possibly buying the organism time to prepare defensive actions. We investigated which aspect of the emotional stimulus content drives this effect: Is the specific valence of fear necessary, or is it an effect of unspecific arousal, for example by speeding up the internal clock? Results Conclusion: Fear modulates the effect of arousal on time-to-contact estimation The results show that shortened time-to-contact judgments are mainly an effect of arousal. However, they are modulated by a number of additional variables. Emotional top-down effects influencing time-to-contact judgments seem to follow the ecologically reframed Yerkes-Dodson Law (Hanoch & Vitouch, 2004): If arousal reaches higher- than-optimum levels, performance is less negatively affected in case of evolutionary relevant (i.e. unpleasant) looming stimuli. More specifically, the effect of arousal on time-to-contact estimation seems to be modulated by specific fears or even by more general trait anxiety, which has been shown to modulate the effects of emotion on basic visual performance such as contrast sensitivity (Ferneyhough et al. 2013). Arousal rather than fear (Experiment 1, N = 14) In contrast to shortened time-to- contact judgments of threatening pictures in a context of neutral pictures (left panel), time-to-contact judgments of threatening pictures were not shortened in a context of pleasantly arousing pictures (right panel). Spider fearfuls (Experiment 2, N = 2 x 20) Spider-fearful observers judged looming pictures of spiders and a frontally attacking dog, snake, or human to arrive earlier than both neutral and arousing pleasant pictures. The control group judged spider pictures to arrive later than all other categories. The latter may be explained by the small size of the depicted spiders (Size-Arrival-Effect; DeLucia, 1991). Disentangling valence and arousal (Experiment 3, N = 30) The more arousing an unpleasant picture, the sooner it was judged to arrive. In contrast, pleasant pictures were judged to arrive earliest (least overestimation) at a medium level of arousal. Notes * and red color indicate significant difference at p < .05. All error bars represent standard error of the mean. pleasant unpleasant more arousing