Experiment Research About Perceptual Sensitivity Of Looming Sound

An object’s motion relative to an observer can ethologically confer meaningful information. Approaching or looming stimuli can signal threats/collisions to be avoided or prey to be confronted, whereas receding stimuli can signal successful escape or failed pursuit. Previous study suggested that relative to equivalent falling level tones, people significantly overestimate the loudness change of approaching stimuli and underestimate their distance. But there is some other researches using different paradigm obtained opposite results. This dissertation want to prove looming sounds are ecologically salient stimuli and explore the reasons.In study one, using movement detection, we investigated the multisensory integration of looming and receding auditory and visual information. To induce the perception of movement, visual stimuli changed in size and auditory stimuli changed in volume so as to give the impression of either looming or receding. The result demonstrated that the movement of looming sound can be detected more quickly and the crossmodal integration can promote the sensitivity.To examine the influence of loudness level on perception, we used 2(low, high)×2(looming, receding)within-subjects design. Participants are requested to detect whether sound is moving or not. Two main effects were significant, that the perception of looming or louder sound is more sensitive. And more importantly, we found the interaction between loudness level and orientation. Looming sound can be detected more accurately when loudness level is high, but this promote is diminished when loudness level is low.We used two experiments to explore the potential mechanism. The error management theory asserted that people tend to make less costly mistakes, because looming sound may have high risk, leading to the participants being sensitive to its perception. According to the emotion priming effect, we predict that the participants’reaction time to angry expressions will be shorter when the prime stimulus is looming sound. In order to prove this point, we used the 3 (anger, fear, happy expression) × 2 (looming sound, receding sound) within-subjects design. The participants were requested to estimate the expression is positive or negative. We found that when the expression was angry, the participants’reaction time was shorter when the prime stimulus was looming sound. For the happy and fear expression, reaction times don’t have significant difference between prime stimulus. The result confirmed that anger expression and looming sound is consistent on emotion valence, completely verified our hypothesis.