Modeling the effect of reward amount on probability discounting

The present study with college students examined the effect of amount on the discounting of probabilistic monetary rewards. A hyperboloid function accurately described the discounting of hypothetical rewards ranging in amount from $20 to $10,000,000. The degree of discounting increased continuously with amount of probabilistic reward. This effect of amount was not due to changes in the rate parameter of the discounting function, but rather was due to increases in the exponent. These results stand in contrast to those observed with the discounting of delayed monetary rewards, in which the degree of discounting decreases with reward amount due to amount-dependent decreases in the rate parameter. Taken together, this pattern of results suggests that delay and probability discounting reflect different underlying mechanisms. That is, the fact that the exponent in the delay discounting function is independent of amount is consistent with a psychophysical scaling interpretation, whereas the finding that the exponent of the probability-discounting function is amount-dependent is inconsistent with such an interpretation. Instead, the present results are consistent with the idea that the probability-discounting function is itself the product of a value function and a weighting function. This idea was first suggested by Kahneman and Tversky (1979), although their prospect theory does not predict amount effects like those observed. The effect of amount on probability discounting was parsimoniously incorporated into our hyperboloid discounting function by assuming that the exponent was proportional to the amount raised to a power. The amount-dependent exponent of the probability-discounting function may be viewed as reflecting the effect of amount on the weighting of the probability with which the reward will be received.     

Introduction: the human sciences and Cold War America

Studies of the history of the human sciences during the Cold War era have proliferated over the past decade--in JHBS and elsewhere. This special issue focuses on the connections between the behavioral sciences and the culture and politics of the Cold War in the United States. In the recent literature, there is a tendency to identify the Cold War human sciences with two main paradigms: that of psychocultural analysis, on the one hand, and of the systems sciences, on the other. The essays in the special issue both extend understanding of each of these interpretive frameworks and help us to grasp their interconnection.     

The Invincible Summer: On Albert Camus’ Philosophical Neoclassicism

What follows is a work of critical reconstruction of Camus' thought. It aims to answer to the wish Camus expressed in his later notebooks, that he at least be read closely. Specifically, I hope to do three things. In Part I, we will show how Camus' famous philosophy of the absurd represents a systematic scepticism whose closest philosophical predecessor is Descartes' method of doubt, and whose consequence, as in Descartes, is the discovery of a single, orienting certainty, on the basis of which Camus would proceed to pass beyond the 'nihilism' that conservative critics continued to level against him (MS 34). Part II will unfold the central tenets of Camus' mature thought of rebellion, and show how Camus' central political claims follow from his para-Cartesian claim to have found an irreducible or 'invincible' basis for a post-metaphysical ethics, consistent with the most thoroughgoing epistemic scepticism. Part III then undertakes to show that the neoclassical rhetoric and positioning Camus claimed for his postwar thought—as a thought of moderation or mesure, and a renewed Greek or Mediterranean naturalism—is more than a stylistic pretension. It represents, so I argue, a singular amalgam of modern and philosophical classical motifs which makes Camus' voice nearly unique in twentieth century ideas, and all the more worth reconsidering today. So let us proceed.     

Association of <Emphasis Type="Italic">ADAM10</Emphasis> and <Emphasis Type="Italic">CAMK2A</Emphasis> Polymorphisms with Conduct Disorder: Evidence from Family-Based Studies

Twin and family studies have shown that genetic factors play a role in the development of conduct disorder (CD). The purpose of this study was to identify genetic variants associated with CD using a family-based association study. We used 4,720 single nucleotide polymorphisms (SNPs) from the Illumina Panel and 11,120 SNPs from the Affymetrix 10K GeneChips genotyped in 155 Caucasian nuclear families from Genetic Analysis Workshop (GAW) 14, a subset from the Collaborative Study on the Genetics of Alcoholism (COGA). 20 SNPs had suggestive associations with CD (p < 10⁻³), nine of which were located in known genes, including ADAM10 (rs383902, p = 0.00036) and CAMK2A (rs2053053, p = 0.00098). Our results were verified using the International Multi-Center ADHD Genetics Project (IMAGE) dataset. In conclusion, we identified several loci associated with CD. Especially, the two genes (ADAM10 and CAMK2A) have been reported to be associated with Alzheimer’s disease, bipolar disorder and depression. These findings may serve as a resource for replication in other populations.     

The Dopamine Receptor D4 Gene (<Emphasis Type="Italic">DRD4</Emphasis>) Moderates Family Environmental Effects on ADHD

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prime candidate for exploration of gene-by-environment interaction (i.e., G x E), particularly in relation to dopamine system genes, due to strong evidence that dopamine systems are dysregulated in the disorder. Using a G x E design, we examined whether the DRD4 promoter 120-bp tandem repeat polymorphism, previously associated with ADHD, moderated the effects of inconsistent parenting and marital conflict on ADHD or Oppositional-Defiant Disorder (ODD). Participants were 548 children with ADHD and non-ADHD comparison children and their parents. Homozygosity for the DRD4 promoter 120-bp tandem repeat insertion allele increased vulnerability for ADHD and ODD only in the presence of inconsistent parenting and appeared to increase susceptibility to the influence of increased child self-blame for marital conflict on ADHD inattention. DRD4 genotypes may interact with these proximal family environmental risk factors by increasing the individual’s responsivity to environmental contingencies.     

Conservatives Anticipate and Experience Stronger Emotional Reactions to Negative Outcomes

The present work examined whether conservatives and liberals differ in their anticipation of their own emotional reactions to negative events. In two studies, participants imagined experiencing positive or negative outcomes in domains that do not directly concern politics. In Study 1, 190 American participants recruited online (64 male, M_age = 32 years) anticipated their emotional responses to romantic relationship outcomes. In Study 2, 97 Canadian undergraduate students (26 male, M_age = 21 years) reported on their anticipated and experienced emotional responses to academic outcomes. In both studies, more conservative participants predicted they would feel stronger negative emotions following negative outcomes than did more liberal participants. Furthermore, a longitudinal follow‐up of Study 2 participants revealed that more conservative participants actually felt worse than more liberal participants after receiving a lower‐than‐desired exam grade. These effects remained even when controlling for the Big Five traits, prevention focus, and attachment style (Study 1), and optimism (Study 2). We discuss how the relationship between political orientation and anticipated affect likely contributes to differences between conservatives and liberals in styles of decision and policy choices.     

The effects of environmental support and secondary tasks on visuospatial working memory

In the present experiments, we examined the effects of environmental support on participants’ ability to rehearse locations and the role of such support in the effects of secondary tasks on memory span. In Experiment 1, the duration of interitem intervals and the presence of environmental support for visuospatial rehearsal (i.e., the array of possible memory locations) during the interitem intervals were both manipulated across four tasks. When support was provided, memory spans increased as the interitem interval durations increased, consistent with the hypothesis that environmental support facilitates rehearsal. In contrast, when environmental support was not provided, spans decreased as the duration of the interitem intervals increased, consistent with the hypothesis that visuospatial memory representations decay when rehearsal is impeded. In Experiment 2, the ratio of interitem interval duration to intertrial interval duration was kept the same on all four tasks, in order to hold temporal distinctiveness constant, yet forgetting was still observed in the absence of environmental support, consistent with the decay hypothesis. In Experiment 3, the effects of impeding rehearsal were compared to the effects of verbal and visuospatial secondary processing tasks. Forgetting of locations was greater when presentation of to-be-remembered locations alternated with the performance of a secondary task than when rehearsal was impeded by the absence of environmental support. The greatest forgetting occurred when a secondary task required the processing visuospatial information, suggesting that in addition to decay, both domain-specific and domain-general effects contribute to forgetting on visuospatial working memory tasks.     

Threats to the Internal Validity of Spinal Surgery Outcome Assessment: Recalibration Response Shift or Implicit Theories of Change?

A recalibration response shift will cause the patient to think about a self-report measure’s response options differently after a health state change. Commonly assessed using the retrospective-pretest design (“then-test”), recent guidelines suggest adjusting then-test estimates for competing explanations. This prospective longitudinal study investigated recalibration response shift after adjusting for implicit theories of change in patients undergoing spinal surgery. The Oswestry Disability Index (ODI) and Short Form-36 (SF-36) were collected before surgery and at 6 weeks and 3 months after spinal decompression surgery. Then-tests of the measures were also collected at all post-tests. Recalibration response shift was operationalized as the then-minus-pre difference score on the evaluative SF-36. Implicit theories of change were operationalized as the then-minus-pre difference score on the perception-based ODI. Improved vs. No-Effect patient groups were compared using the Minimally Important Difference (±15 points) as a cut-off on the Visual Analogue Scale (VAS) items for back and leg pain. Logistic regression analyses investigated whether recalibration response shift had an independent effect distinguishing patient groups, after adjusting for implicit theories of change. The sample (baseline n?=?169, mean age 52, 39 % female) was well-educated, and 1/3 were working. All then-minus-pre difference scores were non-zero at each time point and were stable over time. In the adjusted models distinguishing Improved versus No Effect groups, then-minus-pre ODI difference scores were significant in the majority of the adjusted models at all timepoints, but only one then-minus-pre SF-36 difference score—for physical functioning recalibration—was significant and only at 6-weeks post-surgery. This suggests that implicit theories of change bias the estimation of post-surgical outcomes, but that recalibration response shift biased only the estimation of physical functioning and only at 6 weeks post-surgery. Recalibration response shift and implicit theories of change can both be sources of bias in patient-reported outcome assessment. Our findings suggest that implicit theories of change are a greater threat to validity in this patient sample. Future research using the then-test should control for implicit theories of change to minimize misspecification of effects.     

Meta-Analysis of the Effects of Computerized Cognitive Training on Executive Functions: a Cross-Disciplinary Taxonomy for Classifying Outcome Cognitive Factors

The growing prevalence of neurodegenerative disorders associated with aging and cognitive decline has generated increasing cross-disciplinary interest in non-pharmacological interventions, such as computerized cognitive training (CCT), which may prevent or slow cognitive decline. However, inconsistent findings across meta-analytic reviews in the field suggest a lack of cross-disciplinary consensus and on-going debate regarding the benefits of CCT. We posit that a contributing factor is the lack of a theoretically-based taxonomy of constructs and representative tasks typically used. An integration of the Cattell-Horn-Carroll (CHC) taxonomy of broad and narrow cognitive factors and the Miyake unity-diversity theory of executive functions (EF) is proposed (CHC-M) as an attempt to clarify this issue through representing and integrating the disciplines contributing to CCT research. The present study assessed the utility of this taxonomy by reanalyzing the Lampit et al. (2014) meta-analysis of CCT in healthy older adults using the CHC-M framework. Results suggest that: 1) substantively different statistical effects are observed when CHC-M is applied to the Lampit et al. meta-analytic review, leading to importantly different interpretations of the data; 2) typically-used classification practices conflate Executive Function (EF) tasks with fluid reasoning (Gf) and retrieval fluency (Gr), and Attention with sensory perception; and 3) there is theoretical and practical advantage in differentiating attention and working-memory tasks into the narrow shifting, inhibition, and updating EF domains. Implications for clinical practice, particularly for our understanding of EF are discussed.