Pupil dilation: What does it measure

This article talks about the usefulness of pupil dilation in studying advertising effectiveness in the U.S. A popular and allegedly valid non-verbal measure of psychological response to visual stimuli is the pupillometer. Developed as an academic research tool to monitor and measure the linkage of pupil dilation and constriction to ongoing mental activity, it was later adopted for commercial use. Typical application has been to problems of evaluating advertising materials, packages, and products, which has led to a growing conviction that in many areas of consumer research one might make better predictions of behavior from pupil responses than from verbal or opinion data. Unfortunately, in the field of consumer research in general and advertising research in particular, the need for objective measures of psychological responses to various stimuli materials often leads to the practice of adopting a technique as a useful predictor of human behavior without first thoroughly investigating the technique. The utilization of the pupil dilation technique as a measure of the effectiveness of advertisements is a prime example of this fallacious strategy on the part of advertising researchers.