pressing one of four keys on a QWERTY keyboard corresponding to the four quadrants, and the response times were recorded. 3. Results: 4. Conclusion:.
The Advantage of Fear Stimuli in Accessing Visual Awareness Nuno Gomes , Samuel Silva , Carlos F. Silva , Sandra Xavier & Sandra C. Soares 1
2
3
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1Institute
of Health Sciences, Portuguese Catholic University, Portugal 2DETI / IEETA - University of Aveiro, Portugal 3Center for Health Technology and Services Research (CINTESIS-UA), Department of Education, University of Aveiro, Portugal 4Psychological Medicine Department, Faculty of Medicine, University of Coimbra, Portugal 5Department of Clinical Neuroscience, Division for Psychology, Karolinska Institutet, Sweden
1. Introduction: Evolutionary relevant fear stimuli (e.g.: snakes and spiders) hold a privileged access to the fear module (Ohman et al., 2001; Soares, et al., 2014), an independent behavioral, psychophysiological and neural system that is automatically and selectively activated, and is relatively encapsulated from more advanced human cognition (Ohman & Mineka, 2001). However, no study has directly assessed whether such stimuli are granted a facilitated access to visual awareness (compared to innocuous stimulus, such as birds). In the present study we used an interocular suppression technique, the Continuous Flash Suppression (Tsuchiya & Koch, 2005), known to reduce the activity along the geniculostriate pathway and to strongly suppress processing in the visual cortex (Lin & He, 2009). Our goal was to investigate whether ecologically relevant fear stimuli (snakes and spiders) overcame suppression and accessed awareness (breaking-CFS; Jiang et al., 2007) faster than non-evolutionary relevant animal stimuli (birds).
2. Method: 2.3 Stimuli
2.1 Participants 32 healthy participants (9 men) aged 18 to 35 (M = 22,03 ; SD = 0.69), with right ocular dominance (assessed with Miles’ test).
30 grayscale images of snakes, spiders and birds, with no statistically significant differences (p >0.05 in all cases) in spatial frequency bands and luminance.
2.2 CFS masks 2.4 Display CFS masks were constituted for several Mondrian-like patterns animated at 10Hz.
To use CFS technique with “anaglyph 3D glasses" the stimuli were presented using the blue RGB channel and the CFS masks using the red RGB channel.
2.5 Procedure
Participants were instructed to identify, as quickly and accurately as possible, in which quadrant a stimulus became visible. This was accomplished by pressing one of four keys on a QWERTY keyboard corresponding to the four quadrants, and the response times were recorded.
3. Results: Mean response times to access to visual awareness (ms)
The results showed a significant main effect of animal stimuli [F(2, 62) = 26.35, p < 0.001, η2p = 0.46]. Fear stimuli, spiders and snakes (M = 3706.01 ms; SD = 177.89, and M = 3750.14 ms; SD = 171.95, respectively) accessed visual awareness faster than birds (M = 3968.11 ms SD = 177.73), as shown by Bonferroni post-hoc comparisons (*** p< 0.001). No significant differences were found between spiders and snakes (p > 0.05).
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4000 3950 3900 3850 3800 3750 3700 3650 3600 3550
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Spiders
Snakes
Birds
4. Conclusion: Our findings support the notion that relevant stimuli hold a privileged access into awareness, most likely involving a direct brainstem-thalamic route to the amygdala (Lin & He, 2009). Importantly, they contribute to elucidate the functions and mechanisms of the fear system and may have important implications for understanding emotional disorders, since many of these involve the fear system (LeDoux, 1996; Ohman & Mineka, 2001). References: Jiang, Y., Costello, P., & He, S. (2007). Processing of Invisible Stimuli. Psyc, 18(4), 349–355. doi:10.1111/j.1467-9280.2007.01902.x Ledoux, J. (1996). The Emotional Brain: The Mysterious Underpinnings of Emotional Life. New York: Shuster Sa. Lin, Z., & He, S. (2009). Seeing the invisible: The scope and limits of unconscious processing in binocular rivalry. Progress in Neurobiology, 87(4), 195–211. Öhman, A, & Mineka, S. (2001). Fears, phobias, and preparedness: toward an evolved module of fear and fear learning. Psychological Review, 108(3), 483–522. Öhman, A., Flykt, A., & Esteves, F. (2001). Emotion drives attention: detecting the snake in the grass. Journal of Experimental Psychology. General, 130, 466–478. Soares, S. C., Lindström, B., Esteves, F., & Öhman, A. (2014). The Hidden Snake in the Grass: Superior Detection of Snakes in Challenging Attentional Conditions. PloS One, 9(12), e114724. Tsuchiya, N., & Koch, C. (2005). Continuous flash suppression reduces negative afterimages. Nature Neuroscience, 8(8), 1096–1101.
