Recognizing threat: a simple geometric shape activates neural circuitry for threat detection.

The urgent need to recognize danger quickly has been shown to rely on preferential processing in dedicated neural circuitry. In previous behavioral studies examining the pattern of the face when displaying anger, we found evidence that simple noncontextual geometric shapes containing downward-pointing V-shaped angles activate the perception of threat. We here report that the neural circuitry known to be mobilized by many realistic, contextual threatening displays is also triggered by the simplest form of this V-shaped movement pattern, a downward-pointing triangle. Specifically, we show that simple geometric forms containing only downward-pointing V-shapes elicit greater activation of the amygdala, subgenual anterior cingulate cortex, superior temporal gyrus, and fusiform gyrus, as well as extrastriate visual regions, than do presentations of the identical V-shape pointing upward. Thus, this simple V-shape is capable of activating neural networks instantiating detection of threat and negative affect, suggesting that recognition of potential danger may be based, in part, on very simple, context-free visual cues.