A Web-based study of cerebral asymmetry for perception of emotion.

Many studies have examined cerebral asymmetry via lateralized presentation of stimuli using specialized software. Because these studies typically require extensive control over variables such as stimulus exposure duration, size, location, and so forth, they are not easily transferred to the World Wide Web. The present study replicated a free-vision, chimeric faces task via the Internet, using HTML and JavaScript. Previous results had shown that right-handed participants tend to perceive a chimeric face with a smile to their (the viewers') left as happier than its mirror image. That result was replicated in the Web-based study, and the leftward bias was actually significantly greater than that found using the traditional pencil-and-paper version of the task. Possible reasons for this difference are discussed.