A Dual-Process Discrete-Time Survival Analysis Model: Application to the Gateway Drug Hypothesis

The gateway drug model is a popular conceptualization of a progression most substance users are hypothesized to follow as they try different legal and illegal drugs. Most forms of the gateway hypothesis are that “softer” drugs lead to “harder,” illicit drugs. However, the gateway hypothesis has been notably difficult to directly test—that is, to test as competing hypotheses in a single model that licit drug use might lead to illicit drug use or the reverse. This article presents a novel statistical technique, dual-process discrete-time survival analysis, which enables this comparison. This method uses mixture-modeling software to estimate 2 concurrent time-to-event processes and their effects on each other. Using this method, support for the gateway hypothesis in the National Longitudinal Survey of Youth, 1997, was weak. However, this article was not designed as a strong test of causal direction but more as a technical demonstration and suffered from certain technological limitations. Both these limitations and future directions are discussed.     

Basal ganglia, dopamine and temporal processing: performance on three timing tasks on and off medication in Parkinson's disease

A pervasive hypothesis in the timing literature is that temporal processing in the milliseconds and seconds range engages the basal ganglia and is modulated by dopamine. This hypothesis was investigated by testing 12 patients with Parkinson's disease (PD), both 'on' and 'off' dopaminergic medication, and 20 healthy controls on three timing tasks. In a seconds range (30-120 s) time production task, patients tested 'on' medication showed a significantly different accuracy profile compared to controls and when tested 'off' medication. However, no group or on vs off medication differences in accuracy were found on a time reproduction task and a warned reaction time task requiring temporal processing within the 250-2000 ms range. Variability was measured using the coefficient of variation, with the performance of the patient group on the time reproduction task violating the scalar property, suggesting atypical temporal processing mechanisms. The data suggest that the integrity of the basal ganglia is necessary for 'typical' time production in the seconds range as well as for time reproduction at shorter intervals. Exploratory factor analysis suggested that the time production task uses neural mechanisms distinct from those used in the other two timing tasks. The dissociation of the effects of dopaminergic medication and nature of task on performance in PD raises interesting questions about the pharmacological mediation and task-specificity of deficits in temporal processing.     

Cues to deception

Do people behave differently when they are lying compared with when they are telling the truth? The combined results of 1,338 estimates of 158 cues to deception are reported. Results show that in some ways, liars are less forthcoming than truth tellers, and they tell less compelling tales. They also make a more negative impression and are more tense. Their stories include fewer ordinary imperfections and unusual contents. However, many behaviors showed no discernible links, or only weak links, to deceit. Cues to deception were more pronounced when people were motivated to succeed, especially when the motivations were identity relevant rather than monetary or material. Cues to deception were also stronger when lies were about transgressions.     

A Randomized Trial of Two Promising Computer-Based Interventions for Students with Attention Difficulties

Few studies have examined whether attention can be improved with training, even though attention difficulties adversely affect academic achievement. The present study was a randomized-controlled trial evaluating the impact of Computerized Attention Training (CAT) and Computer Assisted Instruction (CAI) on attention and academic performance in 77 inattentive first graders. Students receiving either intervention were more likely than controls to show a moderate decline in teacher rated attention problems in first grade. Students receiving CAI also showed gains in reading fluency and in teacher ratings of academic performance. Intervention effects for attention were absent by second grade largely because attention problems declined in all groups. However, post hoc analyses indicated potential longer-term benefits for children with 6 or more inattentive symptoms at baseline. Persistent attention problems were associated with poorer academic performance in multiple domains. Results provide initial evidence that CAT and CAI can improve children’s attention in the classroom - and support additional studies to determine whether more clinically significant benefits are attainable.     

Is It a Name or a Fact? Disambiguation of Reference Via Exclusivity and Pragmatic Reasoning

Adults reason by exclusivity to identify the meanings of novel words. However, it is debated whether, like children, they extend this strategy to disambiguate other referential expressions (e.g., facts about objects). To further inform this debate, this study tested 41 adults on four conditions of a disambiguation task: label/label, fact/fact, label/fact, and fact/label (Scofield & Behrend, 2007 ). Participants also provided a verbal explanation for their referent selections to tease apart the underlying processes. Results indicated that adults successfully discerned the target object in the label/label and label/fact condition, yet not the remaining two conditions. Verbal reports indicated that the strategy utilized to disambiguate differed depending upon communicative context. These findings confirm that the tendency to reason by exclusivity becomes restricted to word‐learning situations with growing linguistic and communicative experience.     

A 12-Year Prospective Study of Patterns of Social Information Processing Problems and Externalizing Behaviors

This study investigated how discrete social information processing (SIP) steps may combine with one another to create distinct groups of youth who are characterized by particular patterns of SIP. SIP assessments were conducted on a community sample of 576 children in kindergarten, with follow-up assessments in grades 3, 8, and 11. At each age, four profiles were created, representing youth with no SIP problems, with early step SIP problems (encoding or making hostile attributions), with later step SIP problems (selecting instrumental goals, generating aggressive responses, or evaluating aggression positively), and with pervasive SIP problems. Although patterns of SIP problems were related to concurrent externalizing during elementary school, the consistency between cognition and future externalizing behavior was not as strong in elementary school as it was between grades 8 and 11. In some cases, youth characterized by the co-occurrence of problems in early and later SIP steps had higher externalizing scores than did youth characterized by problems in just one or the other.