Present-Biased Preferences Associated with Socioeconomic Status in Intertemporal Decision-Making: Evidence from Behavioral and Electroencephalographic Measures

Background: The role of socioeconomic status (SES) in individual intertemporal decision-making has received widespread research attention. However, findings regarding its underlying psychological mechanisms remain inconclusive. This study investigates not only the association between SES and intertemporal decision-making but also the underlying cognitive neural mechanisms from both behavioral and electrophysiological perspectives. Methods: Individuals with high and low SES were recruited. In Experiment 1, a behavioral experiment used the Monetary Choice Questionnaire to measure delay discounting rates using the Kirby method and hierarchical Bayesian modeling, as well as choice consistency using the inverse temperature parameter of the softmax function, to examine differences in decision-making between the two groups. In Experiment 2, event-related potential techniques were employed to examine differences in dynamic neural activity during an intertemporal choice task between the high- and low-SES groups. Results: The behavioral results revealed that, in Experiment 1, the low-SES group exhibited a larger delay discounting rate than the high-SES group. The hierarchical Bayesian modeling further indicated that the low-SES group had lower choice consistency. Experiment 2 found that the low-SES group showed a significantly higher proportion of smaller-sooner (SS) choices than the high-SES group. Electroencephalographic results revealed that, compared with the high-SES group, the low-SES group exhibited larger P200 amplitudes but smaller N2 and P300 amplitudes. Within the high-SES group, the larger-later (LL) option elicited more negative N2 and larger P300 amplitudes than the SS option. Conversely, in the low-SES group, P300 amplitudes did not differ significantly between the SS and LL options during the later stage of intertemporal decision-making. Conclusions: The results showed that the low-SES group was more inclined toward immediate gains, made more random choices, displayed higher variability, relied more on intuitive heuristic strategies, and exhibited weaker cognitive control and reduced cognitive resource allocation during intertemporal decision-making. However, at the later stage, the absence of a significant difference between SS and LL options provided preliminary EEG evidence consistent with the possibility that individuals in the low-SES group did not completely disregard future outcomes.