Automatic evaluation of visual symmetry

Artists have always considered symmetry and beauty to be related, while animals are known to prefer symmetrical mates. It seems that the neural mechanisms that detect symmetry are linked to those which mediate positive affect. However, the nature of this link is uncertain. It could be that symmetry automatically elicits a positive response. Alternatively, the affective response may only happen when attempting explicit aesthetic judgment. In order to explore the automatic evaluation hypothesis, we conducted two behavioral studies. First, we found that English words with positive valence (based on ANEW data set) are pronounced more quickly when presented on top of a symmetrical dot pattern than a random dot pattern. Second, we used the Implicit Association Test (IAT) and found that symmetrical patterns were associated with positive words, and random patterns were associated with negative words. These results imply that symmetry is indeed evaluated automatically, even in the absence of explicit instruction. We have also recorded electroencephalographic (EEG) data from 64 scalp electrodes and electromyographic (EMG) data from the Zygomaticus Major (ZM, smiling muscle) while our participant’s viewed symmetrical or random visual dot-patterns. We hypothesize that symmetrical patterns will produce a known pattern of Event Related Potential (ERP) activity at posterior electrodes, and that this will be followed by activation of the ZM. In summary, this program of behavioral and electrophysiological research suggests that visual symmetry automatically elicits positive affect, and promises to uncover the time-course and neural basis of this connection