Predicting purchase decision: The role of hemispheric asymmetry over the frontal cortex.

This article examines how approach motivation as indexed by electroencephalographic (EEG) asymmetry over the prefrontal cortex predicts purchase decision when brand and price are varied. In a within-subjects design, the participants were presented purchase decision trials with 14 different grocery products (seven private label and seven national brand products) whose prices were increased and decreased while their EEG activity was recorded. The results showed that relatively greater left frontal activation (i.e., higher approach motivation) during the predecision period predicted an affirmative purchase decision. The relationship of frontal EEG asymmetry with purchase decision was stronger for national brand products compared with private label products and when the price of a product was below a normal price (i.e., implicit reference price) compared with when it was above a normal price. Higher perceived need for a product and higher perceived product quality were associated with greater relative left frontal activation.