P3b as an electroencephalographic index of automatic associations of exercise-related images

Objective: Interest in automatic associations of exercise and physical activity as potential contributors to behavior is rising. However, the measurement of these associations presents a challenge, since the reliability and validity of behavioral tests (despite their widespread usage) is unsatisfactory by most accounts. As a possible alternative, an electroencephalographic (EEG) index (i.e., P3b amplitude) was examined in the present study. Design: We used a mixed-factor design, with one group of insufficiently and one group of sufficiently physically active participants being compared across different experimental conditions. Methods: Thirty-seven insufficiently and thirty-six sufficiently active participants viewed exercise-related images presented within series of negative, neutral, or positive images and rated all images as negative (unpleasant) or positive (pleasant) while EEG recordings were obtained. The amplitude of the P3b component of the EEG-derived event-related potential, time-locked to the onset of exercise images in each context (series), was extracted as the dependent variable. Results: Insufficiently active participants rated the exercise-related images as neutral-to-positive, whereas sufficiently active participants rated the images as positive. However, all participants exhibited the smallest P3b amplitude when the images were presented in the neutral context, suggesting that the images were registering as neutral. Conclusion: Exercise-related images may evoke neutral automatic associations, but these associations may differ from how individuals reflectively rate the same images. P3b amplitude may be useful in detecting such discrepancies and potentially a promising (evidence-based) option for assessing automatic associations of exercise stimuli.