Emotional bias for the perception of rising tones

Paper in proceeding, 2008

Sounds with rising or falling intensity are often perceived as approaching or receding sound sources, respectively. Research has shown the existence of biases, both at perceptual and neural levels, in detecting and responding to approaching versus receding sounds. It has been suggested that these effects might account for a greater biological salience of approaching sounds. In the present study we investigated whether this asymmetry could be also explained by emotional theories. Participants were exposed to pairs of stimuli formed by an approaching or a receding sound, followed by a neutral, negative or positive photograph. They were required to make a speeded three-alternative forced choice (3AFC) task regarding how they felt when looking at the photographs. Reaction times (RTs) to this task and self-reported emotional ratings for the sounds were collected. In addition, participants' electrodermal activity and facial electromyography were measured as they listened to the sounds. Participants performed faster in the 3AFC task when photographs were preceded by approaching sounds, especially for photographs with negative content. Both the intensity range and slope of the sounds had a significant effect on RTs. Taken together, these results suggest that approaching sounds have a greater emotional power than receding ones.