Kodi B. Arfer

Electrocortical reactivity to social feedback in youth: A pilot study of the Island Getaway task

Highlights • Event-related potential measure of reactivity to social feedback in youth.• Youth were more likely to reject peers who previously rejected them.• Feedback negativity (FN) was sensitive to social rejection vs. acceptance feedback.• Symptoms of depression and social anxiety related to behavioral responses and FN.

Neural responses to social and monetary reward in early adolescence and emerging adulthood

Reward processing is often considered to be a monolithic construct, with different incentive types eliciting equivalent neural and behavioral responses. The majority of the literature on reward processing has used monetary incentives to elicit reward-related activity, yet social incentives may be particularly important due to their powerful ability to shape behavior. Findings from studies comparing social and monetary rewards have identified both overlapping and distinct responses. In order to explore whether reward processing is domain general or category specific (i.e., the same or different across reward types), the present study recorded ERPs from early adolescents (ages 12-13) and emerging adults (ages 18-25) while they completed social and monetary reward tasks. Temporospatial principal components analysis revealed morphologically similar reward positivities (RewPs) in the social and monetary reward tasks in each age group. In early adolescents, no significant difference was found between the magnitude of the RewP to social and monetary rewards. In emerging adults, however, the RewP to monetary rewards was significantly larger than the RewP to social rewards. Additionally, responses to feedback between the two tasks were not significantly correlated in either age group. These results suggest that both domain-general and category-specific processes underlie neural responses to rewards and that the relative incentive value of different types of rewards may change across development. Findings from this study have important implications for understanding the role that neural response to rewards plays in the development of psychopathology during adolescence.

The attraction of gambling

If a repeated gamble is subjectively structured into units each consisting of a string of consecutive losses followed by a single win, longer strings will necessarily be less valuable. Longer, less valuable strings will be discounted by delay more than will shorter, more valuable strings. This implies that the whole gambles expected, delay-discounted value will increase as delay discounting increases. With this restructuring, even games of (objectively) negative expected value, such as those at casinos, may be subjectively positive. The steeper the delay discounting, the greater the subjective value of the gamble (over normal ranges of discounting steepness). Frequent gamblers, who value gambles highly, would thus be expected to discount delayed rewards more steeply than would nongamblers.

Sex-related substance use and the externalizing spectrum

BACKGROUND Substance use before and during sexual activity is associated with many negative health outcomes. Estimates suggest that at least 4.3 million American adults annually engage in regular sex-related alcohol consumption, indicating that the intersection of substance use and sexual behavior is of public health concern. However, it is likely that when considering broader sex-related substance use, estimates would be notably higher. While substance use disorders and antisocial personality disorder have been associated with sex-related alcohol consumption, no study has investigated how regular sex-related substance use is associated with the broader transdiagnostic externalizing spectrum. Further, no studies have assessed whether or not sexual risk-taking behaviors can be integrated into the externalizing spectrum. METHODS In a large internet sample (N=936), we used confirmatory factor analysis, item response theory, and logistic regression to link sex-related alcohol and drug use to an externalizing latent variable; identified psychometric characteristics of these behaviors; and determined the extent to which ones externalizing level was associated with changes in odds of regular sex-related substance use. We then replicated these findings in a nationally representative sample (N=34,653). RESULTS Results highlighted the close association between sex-related substance use and externalizing, with externalizing increases being associated with significantly increased odds of regular sex-related substance use. CONCLUSIONS These findings bear notable implications for conceptualization and treatment of sex-related substance use. Transdiagnostic intervention can be an efficient means of addressing this problematic behavior as well as other comorbid presentations. Results expand the current conceptualization of the externalizing spectrum.

Social processing in early adolescence: Associations between neurophysiological, self-report, and behavioral measures

Peer relationships play a major role in adolescent development, but few methods exist for measuring social processing at the neurophysiological level. This study extends our pilot study of Island Getaway, a task for eliciting event-related potentials (ERPs) to peer feedback. We differentiated ERPs using principal components analysis (PCA) and examined associations with behavioral and self-report measures in young adolescents (N=412). PCA revealed an early negativity in the ERP enhanced for rejection feedback, followed by a series of positivities (consistent with reward positivity [RewP], P300, and late positive potential) that were enhanced for acceptance feedback. Greater self-reported task engagement correlated with a larger RewP to acceptance and lower rates of rejecting peers. Youth higher in depressive symptoms exhibited a blunted RewP to social acceptance and reported lower engagement. Results highlight ERP components sensitive to peer feedback that may inform understanding of social processes relevant to typical and atypical development.

Criterion Validity of Self-Reports of Alcohol, Cannabis, and Methamphetamine Use Among Young Men in Cape Town, South Africa

Valid measurement of substance use is necessary to evaluate preventive and treatment interventions. Self-report is fast and inexpensive, but its accuracy can be hampered by social desirability bias and imperfect recall. We examined the agreement between self-report of recent use and rapid diagnostic tests for three substances (alcohol, cannabis, and methamphetamine) among 904 young men living in Cape Town, South Africa. Rapid diagnostic tests detected the respective substances in 32, 52, and 22% of men. Among those who tested positive, 61% (95% CI [56%, 66%]), 70% ([67%, 74%]), and 48% ([42%, 54%]) admitted use. Men were moderately more willing to admit use of cannabis than alcohol (log OR 0.42) or admit use of alcohol than methamphetamine (log OR 0.53). Our findings show that self-report has reasonable criterion validity in this population, but criterion validity can vary substantially depending on the substance.

The predictive accuracy of intertemporal-choice models

How do people choose between a smaller reward available sooner and a larger reward available later? Past research has evaluated models of intertemporal choice by measuring goodness of fit or identifying which decision-making anomalies they can accommodate. An alternative criterion for model quality, which is partly antithetical to these standard criteria, is predictive accuracy. We used cross-validation to examine how well 10 models of intertemporal choice could predict behaviour in a 100-trial binary-decision task. Many models achieved the apparent ceiling of 85% accuracy, even with smaller training sets. When noise was added to the training set, however, a simple logistic-regression model we call the difference model performed particularly well. In many situations, between-model differences in predictive accuracy may be small, contrary to long-standing controversy over the modelling question in research on intertemporal choice, but the simplicity and robustness of the difference model recommend it to future use.

The amount effect and marginal value.

The amount effect of delay discounting (by which the value of larger reward amounts is discounted by delay at a lower rate than that of smaller amounts) strictly implies that value functions (value as a function of amount) are steeper at greater delays than they are at lesser delays. That is, the amount effect and the difference in value functions at different delays are actually a single empirical finding. Amount effects of delay discounting are typically found with choice experiments. Value functions for immediate rewards have been empirically obtained by direct judgment. (Value functions for delayed rewards have not been previously obtained.) The present experiment obtained value functions for both immediate and delayed rewards by direct judgment and found them to be steeper when the rewards were delayed--hence, finding an amount effect with delay discounting.

Reputational concerns, not altruism, motivate restraint when gambling with other people's money

People may behave prosocially not only because they value the welfare of others, but also to protect their own reputation. We examined the separate roles of altruism and reputational concerns in moral-hazard gambling tasks, which allowed subjects to gamble with a partners money. In Study 1, subjects who were told that their partner would see their choices were more prosocial. In Study 2, subjects were more prosocial to a single partner when their choices were transparent than when their choices were attributed to a third party. We conclude that reputational concerns are a key restraint on selfish exploitation under moral hazard.

Reciprocation and altruism in social cooperation

Altruistic behavior benefits other individuals at a cost to oneself. The purpose of the present experiment was to study altruistic behavior by players (P) in 2-person iterated prisoners dilemma games in which reciprocation by the other player (OP) was impossible, and this impossibility was clear to P. Altruism by P could not therefore be attributed to expectation of reciprocation. The cost to P of altruistic behavior was constant throughout the study, but the benefit to OP from Ps cooperation differed between groups and conditions. Rate of cooperation was higher when benefit to OP was higher. Thus altruism (not attributable to expectation of reciprocation) can be a significant factor in interpersonal relationships as studied in iterated prisoners dilemma games, and needs to be taken into account in their analysis.