Bioelectrical echoes from a career at the cutting edge: John Cacioppo's legacy and the use of ERPs in social psychology.

In his many writings, John Cacioppo stressed how neural and physiological events could reveal psychological phenomena. Far from merely "physiologizing" psychology, John advocated social neuroscience in service of theory development and causal inference. These themes can be seen in his ERP work, which he began in the early 1990s to answer basic questions about attitudes. Fortuitously, his foray into ERP research overlapped with the dominance of the social cognition perspective in social psychology, which argues that complex thoughts and behaviors can be understood by breaking them into their underlying elements. ERPs are a natural methodological complement to this perspective, assuming that complex thoughts and behaviors are composed to separable information processing stages that manifest on the scalp as ERPs. Social cognitive theories, with their roots in mental chronometry, are thus fertile ground for researchers possessing a way to quantify underlying mental operations. This review illustrates John's influence by tracing its impact on our own research.