Which sensory organ do you trust: your eyes or your ears? Most people would rather tend to their eyes when it comes to this question. But noises can have a major impact on our perception - even on what we believe to see.
Experts from the University of California at San Diego and the École Polytechnique Fédérale de Lausanne demonstrated how much acoustic stimuli influence our visual perception. They showed 185 subjects schematic illustrations of two objects combined with each other – for example, a mixture of airplane and raven or hammer and seal. These "morphs" were composed of different proportions of both objects. So sometimes there was more aircraft than raven to recognize or vice versa. In addition, the subjects were played sounds at different times during the experiments that either matched one of the two objects or had nothing to do with it.
Afterwards the test subjects should reconstruct what they had just seen. To do this, you should reproduce the right "mixing ratio" of the objects with a slider. It showed: If, for example, a hemerny sound was played, while a mixture of hammer and seal was seen, the test subjects pulled the controller more closely in the direction of hammer than the illustration had made purely visually. They also reacted faster.
However, this effect did not occur when the sound sounded before or after the fading. So it is not about expectations linked to the sound or subsequent reviews of what is seen, the authors conclude. The perception itself is changed by the addition of auditory information. "Our study demonstrates how important it is to examine visual processing as an integrative and not as an isolated process," they write in their publication in the specialist magazine "Psychological Science"
