A mobile EEG investigation of the neural dynamics underpinning real-world economic decisions during product purchasing.

Economic decisions are continuously made throughout daily life and involve subjective value (SV) assignment and subsequent selection of the option with the highest SV amongst competing alternatives. The precise temporal characteristics of early value computation are unknown, and, to date, no research has examined the neural dynamics of subjective valuation in naturalistic environments, which have different perceptual and motivational characteristics which could alter SV. The current thesis examined the spatiotemporal neural dynamics underpinning subjective valuation of products in naturalistic settings using mobile electroencephalography (EEG) and eye-tracking. Eye-movement related potentials (EMRPs) underpinning SV of products were examined in a product gallery for 2-D images, and a custom-built mock shop for real 3-D products. Stimulus onset corresponded to the first instance of the gaze touching an object. Products were viewed and rated whilst mobile electroencephalography and eye-tracking recordings were taken. Willingness to pay (WTP) values were used as a measure of SV and were elicited using a Becker-DeGroot-Marschak (BDM) auction following the mobile EEG task. ICA was used to reduce contamination of eye-movement artefacts. Source dipole modelling was used to estimate cortical generators of EMRP components. Results from three experimental chapters suggest early encoding of unique bands of SVs for 2-D and 3-D products in multiple distinct cortical clusters. Low- and high-value products were discriminated binarily in early latencies of EMRPs, with facilitated encoding of low-value items. Intermediate-value items were discriminated in later components of EMRPs, both within parietal/occipital cortex. Linear encoding of SV was observed for 3-D products. The current thesis demonstrates, using novel methodologies and mobile EEG and eye-tracking recordings in realistic settings, that early SVs assigned to 2-D and 3-D products are computed on a coarse grid, within multiple distinct components of EMRPS within parietal/occipital cortex, with facilitated binary representations of low- and high-value products and later encoding of intermediate-value products