Robin Chark

Social Cognitive Role of Schizophrenia Candidate Gene GABRB2

The occurrence of positive selection in schizophrenia-associated GABRB2 suggests a broader impact of the gene product on population fitness. The present study considered the possibility of cognition-related GABRB2 involvement by examining the association of GABRB2 with psychosis and altruism, respectively representing psychiatric and psychological facets of social cognition. Four single nucleotide polymorphisms (SNPs) were genotyped for quantitative trait analyses and population-based association studies. Psychosis was measured by either the Positive and Negative Syndrome Scale (PANSS) or antipsychotics dosage, and altruism was based on a self-report altruism scale. The minor alleles of SNPs rs6556547, rs1816071 and rs187269 in GABRB2 were correlated with high PANSS score for positive symptoms in a Han Chinese schizophrenic cohort, whereas those of rs1816071 and rs1816072 were associated with high antipsychotics dosage in a US Caucasian schizophrenic cohort. Moreover, strongly significant GABRB2-disease associations were found among schizophrenics with severe psychosis based on high PANSS positive score, but no significant association was observed for schizophrenics with only mild psychosis. Interestingly, in addition to association with psychosis in schizophrenics, rs187269 was also associated with altruism in healthy Han Chinese. Furthermore, parallel to correlation with severe psychosis, its minor allele was correlated with high altruism scores. These findings revealed that GABRB2 is associated with psychosis, the core symptom and an endophenotype of schizophrenia. Importantly, the association was found across the breadth of the psychiatric (psychosis) to psychological (altruism) spectrum of social cognition suggesting GABRB2 involvement in human cognition.

Computational substrates of social norm enforcement by unaffected third parties

Enforcement of social norms by impartial bystanders in the human species reveals a possibly unique capacity to sense and to enforce norms from a third party perspective. Such behavior, however, cannot be accounted by current computational models based on an egocentric notion of norms. Here, using a combination of model-based fMRI and third party punishment games, we show that brain regions previously implicated in egocentric norm enforcement critically extend to the important case of norm enforcement by unaffected third parties. Specifically, we found that responses in the ACC and insula cortex were positively associated with detection of distributional inequity, while those in the anterior DLPFC were associated with assessment of intentionality to the violator. Moreover, during sanction decisions, the subjective value of sanctions modulated activity in both vmPFC and rTPJ. These results shed light on the neurocomputational underpinnings of third party punishment and evolutionary origin of human norm enforcement.

The Bias of Size in Gambling Decisions: Evidence From a Casino Game:

Casino operators strive to motivate gamblers to wager to maximize their gaming revenue. This motivation may be achieved by increasing gamblers’ perceived likelihood of winning, which stems from cognitive bias. Therefore, it is important for casino operators to understand the components that promote cognitive bias in gambling. This study introduces and demonstrates the existence of a bias of size in gambling decisions using a casino game referred to as Cussec. Specifically, participants are expected to bias their choice toward the option of Big (vs. Small) in the game; however, these two options are of equal chance. In the present research, a field observational study and two experimental studies were conducted. In the observational study, the bias was identified using 4,565 Cussec bets that were recorded in a casino in Macao. The bias was further demonstrated in experimental studies that involved Chinese participants (389 participants in the laboratory and 1,000 participants through an online survey platform). The bias is robust against the order of appearance (i.e., Big is displayed before or after Small). The online experiment contributes knowledge to the literature by indicating that gamblers’ bias toward Big distorts their perceived likelihood of winning. It is recommended that casino operators provide more games that feature size cues, and gaming designers incorporate these cues in the design of casino games.

A Room of One’s Own: Need for Uniqueness Counters Online WoM

We examine how consumers’ desire to be different reduces their reliance on others’ suggestions and thus increases their tendency to diverge from the average opinion. While the extant literature focuses on the role of need for uniqueness in attitude formation and choice behavior, not much has been done to test the effect of uniqueness seeking on reactions to persuasive, word of mouth (WoM) messages. In four studies, we find converging evidence for a uniqueness effect. Specifically, the uniqueness motivation interacts with the valence of the average opinion such that when uniqueness motivation is low, consumers follow others’ advice and thus their attitudes depend primarily on the valence of the average opinion; meanwhile, the uniqueness seekers rely less on the valence and are more likely to form less favorable attitudes after reading positive reviews and to hold less unfavorable ones when the reviews are negative. These effects are found when trait need for uniqueness is measured as well as when situational need for uniqueness is manipulated. We further examine the process through which uniqueness motivation results in nonconformist attitudes. Uniqueness seekers perceive minority opinions as more diagnostic. Thus, these minority opinions are disproportionately represented in uniqueness seekers’ nonconformist views. These findings are important to the hospitality industry as consumers often rely on others’ experiences by reading online reviews to help make decisions concerning their own hospitality needs, which are highly experiential in nature.

Price Fairness in the Era of the Sharing Economy

The meaning of price fairness in the sharing economy is examined in four experiments. The results suggest that the sharing economy evokes communal norms that make customers more sensitive to the unfairness of demand-based pricing. Specifically, the four studies demonstrate that (a) framing demand-based pricing as a surcharge is perceived as less fair than framing it as a foregone discount when used by a family on Airbnb but not when used by a hotel on Expedia or a hotel on Airbnb; (b) the effect of host (family vs. hotel) on the perceived fairness of surcharges is diminished when the surcharge is justified with an exchange good (free wifi service) but not when it is justified by a communal good (free cooking instruction); (c) the interaction of host by type of extra good on perceived price fairness is mediated by the activation of communal (vs. exchange) norms; and (d) the host-by-framing interaction has similar effects on booking intention as it does on perceived price fairness.

Boundedly Rational Expectations in Insurance Decision Making: Experimental and Field Evidence

We examine a type of behavioral regularities in insurance decision making, namely instances when consumers do not fully take into account the informational value of the insurer’s offered premium. Specifically, we study scenarios when the consumer is less informed about the loss probability than the insurer. We examine basic violations of rational expectations, with which the consumer overestimates the loss probability beyond what could be inferred from the premise that the insurer must seek to break even or earn a profit over the risk to be covered. We report a field study and an experiment that reveal systematic occurrence of such violations. Violations were especially frequent at low premium levels, and the demand for insurance had an inverted-U dependence on the premium. Our findings suggest that, when consumers form beliefs over the loss probability, they take into account the offered premium to some extent, but often insufficiently so.

Extended Present Bias: A Direct Experimental Test of the Hyperbolic Discounting Hypothesis

In accounting for the phenomenon of present bias, the hyperbolic discounting and quasi-hyperbolic discounting models have distinct predictions beyond today. We provide experimental evidence supporting diminishing rate of discounting beyond present period under careful experimental controls. In three studies involving 1378 subjects in total, the average discount rates assessed in the delayed menus are each significantly lower than those for a more proximate menu. Yet, there is no significant difference between the average discount rates assessed in the delayed menus. Taken together, our findings suggest an extended present bias hypothesis with distinct present and near term bias followed by exponential discounting into the future.