Richard P. Ebstein

Using data from a large-scale behavioral experiment in Beijing, we investigate how social efficiency orientation may relate to rice culture proxied by the rice farming ratio in the subject’s birth province. We find that the observed behavior in several behavioral games that enhances social efficiency is positively associated with the rice farming ratio. This is corroborated by a further analysis of data related to giving help from the China Family Panel Studies. The overall finding supports our hypothesis that rice culture fosters the individual’s intrinsic preference toward greater social efficiency.

Converging evidence suggests that oxytocin (OT) is associated with creative thinking (CT) and that release of OT depends on ADP ribosyl-cyclases (CD38andCD157). Neural mechanisms of CT and OT show a strong association with dopaminergic (DA) pathways, yet the link between CT andCD38,CD157, dopamine receptor D2 (DRD2) and catechol-O-methyltransferase (COMT) peripheral gene expression remain inconclusive, thus limiting our understanding of the neurobiology of CT. To address this issue, two principal domains of CT, divergent thinking (AUT), were assessed. In men, both AUT is associated with gene expression ofCD38,CD157, and their interactionCD38 × CD157. There were no significant associations for DA expression (DRD2,COMT,DRD2 × COMT) on both CT measures. However, analysis of the interactions of OT and DA systems reveal significant interactions for AUT in men. The full model explained a sizable 39% of the variance in females for the total CT score. The current findings suggest that OT and DA gene expression contributed significantly to cognition and CT phenotype. This provides the first empirical foundation of a more refined understanding of the molecular landscape of CT.

The motivation to strive for and consume primary rewards such as palatable food is bound by devaluation mechanisms, yet secondary rewards such as money may not be bound by these regulatory mechanisms. The present study therefore aimed at determining diverging devaluation trajectories for primary (chocolate milk) and secondary (money) reinforcers on the behavioral and neural level. Devaluation procedures with repeated exposure to reward combined with a choice (Experiment 1) and an incentive delay (Experiment 2) paradigm consistently revealed decreasing hedonic value for the primary reward as reflected by decreasing hedonic evaluation and choice preference with repeated receipt, while hedonic value and preferences for the secondary reward increased. Concomitantly acquired functional near-infrared spectroscopy (fNIRS) data during the incentive delay paradigm revealed that increasing value of the secondary reward was accompanied by increasing anticipatory activation in the lateral orbitofrontal cortex, while during the consummatory phase the secondary reinforcer associated with higher medial orbitofrontal activity irrespective of devaluation stage. Overall, the findings suggest that—in contrast to primary reinforcers—secondary reinforcers, i.e. money, can acquire progressively enhanced incentive motivation with repeated receipt, suggesting a mechanism which could promote escalating striving to obtain secondary rewards.

An amendment to this paper has been published and can be accessed via the original article.