ADHD and Behavioral Inhibition: A Re-examination of the Stop-signal Task

The current study investigates two recently identified threats to the construct validity of behavioral inhibition as a core deficit of attention-deficit/hyperactivity disorder (ADHD) based on the stop-signal task: calculation of mean reaction time from go-trials presented adjacent to intermittent stop-trials, and non-reporting of the stop-signal delay metric. Children with ADHD (n = 12) and typically developing (TD) children (n = 11) were administered the standard stop-signal task and three variant stop-signal conditions. These included a no-tone condition administered without the presentation of an auditory tone; an ignore-tone condition that presented a neutral (i.e., not associated with stopping) auditory tone; and a second ignore-tone condition that presented a neutral auditory tone after the tone had been previously paired with stopping. Children with ADHD exhibited significantly slower and more variable reaction times to go-stimuli, and slower stop-signal reaction times relative to TD controls. Stop-signal delay was not significantly different between groups, and both groups’ go-trial reaction times slowed following meaningful tones. Collectively, these findings corroborate recent meta-analyses and indicate that previous findings of stop-signal performance deficits in ADHD reflect slower and more variable responding to visually presented stimuli and concurrent processing of a second stimulus, rather than deficits of motor behavioral inhibition.     

Response Style Differences in the Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

This study examined potential differences between the inattentive and combined ADHD subtypes using laboratory tasks assessing behavioral inhibitory processes. Seventy-five children completed two tasks of behavioral inhibition believed to isolate different processes: the cued reaction time task (CRT), a basic inhibition task, and the go/no-go task (GNG), a complex inhibition task that incorporates motivational contingencies. Three groups of participants were identified, including ADHD/Inattentive (n = 17), ADHD/Combined (n = 37), and comparison (n = 21). Results indicated that rather than showing behavioral inhibition deficits, the ADHD/I children appeared overly inhibited, as evidenced by slower reaction times across the two tasks and significantly higher errors of omission in the GNG task. Additionally, the ADHD/I children did not demonstrate cue dependency effects on the CRT task, suggesting that they were failing to incorporate relevant information before making a response. The sluggish and inhibited performance of the ADHD/I group challenges the idea that it is a subtype of ADHD.     

Coordinating cognition: the costs and benefits of shared gaze during collaborative search

Collaboration has its benefits, but coordination has its costs. We explored the potential for remotely located pairs of people to collaborate during visual search, using shared gaze and speech. Pairs of searchers wearing eyetrackers jointly performed an O-in-Qs search task alone, or in one of three collaboration conditions: shared gaze (with one searcher seeing a gaze-cursor indicating where the other was looking, and vice versa), shared-voice (by speaking to each other), and shared-gaze-plus-voice (by using both gaze-cursors and speech). Although collaborating pairs performed better than solitary searchers, search in the shared gaze condition was best of all: twice as fast and efficient as solitary search. People can successfully communicate and coordinate their searching labor using shared gaze alone. Strikingly, shared gaze search was even faster than shared-gaze-plus-voice search; speaking incurred substantial coordination costs. We conclude that shared gaze affords a highly efficient method of coordinating parallel activity in a time-critical spatial task.     

Taxometric analyses of borderline personality features in a large-scale male and female offender sample

Few studies to date have examined the extent to which borderline personality features are best construed as representing an underlying dimension or a discrete class or taxon. The authors conducted taxometric analyses using a large-scale sample of male (n=787) and female (n=368) prison inmates who had completed the Personality Assessment Inventory (L. C. Morey, 2007). Analyses based on the 4 subscales of the Borderline Features Scale offered compelling support for a dimensional structure in both the full sample and the female subsample--even after controlling for the potentially confounding effects of negative response distortion. Theoretical and pragmatic implications of these findings are reviewed.     

Clinical practice as natural laboratory for psychotherapy research: a guide to case-based time-series analysis

Both researchers and practitioners need to know more about how laboratory treatment protocols translate to real-world practice settings and how clinical innovations can be systematically tested and communicated to a skeptical scientific community. The single-case time-series study is well suited to opening a productive discourse between practice and laboratory. The appeal of case-based time-series studies, with multiple observations both before and after treatment, is that they enrich our design palette by providing the discipline another way to expand its empirical reach to practice settings and its subject matter to the contingencies of individual change. This article is a user's guide to conducting empirically respectable case-based time-series studies in a clinical practice or laboratory setting.     

Contextual control of slot-machine gambling: replication and extension

Participants were trained and tested to select stimuli of differing physical quantities in the presence of 2 color contextual cues for more than and less than. Following more than and less than relational training, participants allocated the majority of their responses to the slot machine that shared formal properties of color with the contextual cue for more than, despite the identical payout probabilities of the slot machines.     

Safety in work vehicles: a multilevel study linking safety values and individual predictors to work-related driving crashes

Although work-related driving is associated with high accident rates, limited research has investigated the factors influencing driving crashes in the work setting. This study explored multilevel influences on self-reported crashes in the workplace by surveying a sample of work-related drivers (n = 380), their workgroup supervisors (n = 88), and fleet managers (n = 47). At the driver level of analysis, safety motivation predicted self-reported crashes. In turn, drivers' perceptions of their fleet managers' safety values (but not drivers' perceptions of their supervisors' safety values), their own attitudes, and their own efficacy beliefs predicted motivation to drive safely. Furthermore, the influence of supervisors and fleet managers interacted such that drivers were more motivated to drive safely if they perceived both their supervisor and fleet manager to value safety. This study also explored the cross-level relationships between supervisors' and fleet managers' perceptions of organizational safety values and drivers' perceptions of managerial safety values and found a relationship between fleet managers' perceptions of organizational safety values and drivers' perceptions of fleet managers' safety values. These results illustrate that perceptions of workplace safety values are transmitted across levels of the organization.     

Prejudice as Self‐Control Failure1

Research has suggested that whereas stereotypical attitudes may be automatically activated, the response to these stereotypes can be controlled. Anything that interferes with self‐control may result in more biased behavior. The ego strength model hypothesizes that after exerting self‐control, subsequent self‐control performance will suffer. Hence, depletion of ego strength may lead to increased prejudice. In 2 studies, depletion was found only to affect individuals who normally try to control their prejudicial responses. Participants who do not normally try to control their use of stereotypes were equally prejudiced, regardless of their level of ego strength. The results have implications for prejudice and stereotyping, as well as models of self‐control.