Hedger Nicholas, Adams Wendy J, Garner Matthew
Psychology Department, University of Southampton.
Clinical and Experimental Sciences, Faculty of Medicine and School of Psychology, University of Southampton.
J Exp Psychol Hum Percept Perform. 2015 Jun;41(3):798-806. doi: 10.1037/xhp0000051. Epub 2015 Apr 13.
The rapid detection and evaluation of threat is of fundamental importance for survival. Theories suggest that this evolutionary pressure has driven functional adaptations in a specialized visual pathway that evaluates threat independently of conscious awareness. This is supported by evidence that threat-relevant stimuli rendered invisible by backward masking can induce physiological fear responses and modulate spatial attention. The validity of these findings has since been questioned by research using stringent, objective measures of awareness. Here, we use a modified continuous flash suppression paradigm to ask whether threatening images induce adaptive changes in autonomic arousal, attention, or perception when presented outside of awareness. In trials where stimuli broke suppression to become visible, threatening stimuli induced a significantly larger skin conductance response than nonthreatening stimuli and attracted spatial attention over scrambled images. However, these effects were eliminated in trials where observers were unaware of the stimuli. In addition, concurrent behavioral data provided no evidence that threatening images gained prioritized access to awareness. Taken together, our data suggest that the evaluation and spatial detection of visual threat are predicted by awareness.
对威胁的快速检测和评估对生存至关重要。理论表明，这种进化压力促使了一种专门视觉通路的功能适应，该通路独立于意识觉知来评估威胁。有证据支持这一点，即通过反向掩蔽使其不可见的与威胁相关的刺激可以诱发生理恐惧反应并调节空间注意力。自那时起，这些发现的有效性受到了使用严格、客观的觉知测量方法的研究的质疑。在这里，我们使用一种改良的连续闪光抑制范式来探究当威胁性图像在意识之外呈现时，是否会引起自主唤醒、注意力或感知方面的适应性变化。在刺激打破抑制变得可见的试验中，威胁性刺激比非威胁性刺激诱发了显著更大的皮肤电导反应，并且在与加扰图像相比时吸引了空间注意力。然而，在观察者未意识到刺激的试验中，这些效应被消除了。此外，同时的行为数据没有提供证据表明威胁性图像获得了优先进入意识的机会。综合来看，我们的数据表明视觉威胁的评估和空间检测是由意识预测的。
