Predictive value of body posture and pupil dilation in assessing consumer preference and choice

In neuroeconomics and neuromarketing, the assessment of arousal has become one of the key measures in our effort to understand the basic mechanisms of value-based choice. While neurophysiological responses such as pupil dilation and galvanic skin response (GSR) have provided a significant explanatory value in our understanding of decision making, other, less known responses such as body posture, may provide additional explanatory value. Here, we report the results from three separate high-resolution eye-tracking studies in which pupil dilation and body posture provide both independent and interacting contributions in predicting preference judgments and choice. Notably, our data suggest that a combination of pupil dilation and posture can be used to assess arousal and valence, respectively, and thus provide a better estimate of emotional responses to stimuli, and their effect on choice. However, the use of this combined measure needs to be used with care, as the dynamic relationship between pupil size and posture is affected by different categories of stimuli. We discuss these findings in light of the academic and commercial call for neuroimaging and physiology measures that can predict and explain the causal mechanisms underlying preference formation and value based choice.