Competing Core Processes in Attention-Deficit/Hyperactivity Disorder (ADHD): Do Working Memory Deficiencies Underlie Behavioral Inhibition Deficits?

The current study examined competing predictions of the working memory and behavioral inhibition models of ADHD. Behavioral inhibition was measured using a conventional stop-signal task, and central executive, phonological, and visuospatial working memory components (Baddeley 2007) were assessed in 14 children with ADHD and 13 typically developing (TD) children. Bootstrapped mediation analyses revealed that the visuospatial working memory system and central executive both mediated the relationship between group membership (ADHD, TD) and stop-signal task performance. Conversely, stop-signal task performance mediated the relationship between group membership and central executive processes, but was unable to account for the phonological and visuospatial storage/rehearsal deficits consistently found in children with ADHD. Comparison of effect size estimates for both models suggested that working memory deficits may underlie impaired stop-signal task performance in children with ADHD. The current findings therefore challenge existing models of ADHD that describe behavioral inhibition as a core deficit of the disorder.     

Environmental Contributions to the Stability of Antisocial Behavior over Time: Are They Shared or Non-shared?

It has recently been argued that shared environmental influences are moderate, identifiable, and persistent sources of individual differences in most forms of child and adolescent psychopathology, including antisocial behavior. Unfortunately, prior studies examining the stability of shared environmental influences over time were limited by possible passive gene-environment correlations, shared informants effects, and/or common experiences of trauma. The current study sought to address each of these limitations. We examined adolescent self-reported antisocial behavior in a 3.5 year longitudinal sample of 610 biological and adoptive sibling pairs from the Sibling Interaction and Behavior Study (SIBS). Results revealed that 74–81% of shared environmental influences present at time 1 were also present at time 2, whereas most non-shared environmental influences (88–89%) were specific to a particular assessment period. Such results provide an important constructive replication of prior research, strongly suggesting that shared environmental contributions to antisocial behavior are systematic in nature.     

The effects of temporal delay and orientation on haptic object recognition

We examined the effects of interstimulus interval (ISI) and orientation changes on the haptic recognition of novel objects, using a sequential shape-matching task. The stimuli consisted of 36 wedge-shaped plastic objects that varied along two shape dimensions (hole/bump and dip/ridge). Two objects were presented at either the same orientation or a different orientation, separated by either a short (3-sec) ISI or a long (15-sec) ISI. In separate conditions, ISI was blocked or randomly intermixed. Participants ignored orientation changes and matched on shape alone. Although performance was better in the mixed condition, there were no other differences between conditions. There was no decline in performance at the long ISI. There were similar, marginally significant benefits to same-orientation matching for short and long ISIs. The results suggest that the perceptual object representations activated from haptic inputs are both stable, being maintained for at least 15 sec, and orientation sensitive.     

Examination of gaze behaviors under in situ and video simulation task constraints reveals differences in information pickup for perception and action

Queensland University of Technology, Brisbane, Queensland, Australia Gaze and movement behaviors of association football goalkeepers were compared under two video simulation conditions (i.e., verbal and joystick movement responses) and three in situ conditions (i.e., verbal, simplified body movement, and interceptive response). The results showed that the goalkeepers spent more time fixating on information from the penalty kick taker’s movements than ball location for all perceptual judgment conditions involving limited movement (i.e., verbal responses, joystick movement, and simplified body movement). In contrast, an equivalent amount of time was spent fixating on the penalty taker’s relative motions and the ball location for the in situ interception condition, which required the goalkeepers to attempt to make penalty saves. The data suggest that gaze and movement behaviors function differently, depending on the experimental task constraints selected for empirical investigations. These findings highlight the need for research on perceptual— motor behaviors to be conducted in representative experimental conditions to allow appropriate generalization of conclusions to performance environments.     

Artificial Intelligence, Religion, and Community Concern

Future developments in artificial intelligence (AI) will likely allow for a greater degree of human-machine convergence, with machines becoming more humanlike and intelligent machinery becoming more integrated into human brain function. This will pose many ethical challenges, and the necessity for a moral framework for evaluating these challenges will grow. This paper argues that community concern constitutes a central factor in both the evolution of religion and the human brain, and as such it should be used as the organizing principle for moral evaluations of AI technologies.     

Working Memory Deficits and Social Problems in Children with ADHD

Social problems are a prevalent feature of ADHD and reflect a major source of functional impairment for these children. The current study examined the impact of working memory deficits on parent- and teacher-reported social problems in a sample of children with ADHD and typically developing boys (N = 39). Bootstrapped, bias-corrected mediation analyses revealed that the impact of working memory deficits on social problems is primarily indirect. That is, impaired social interactions in children with ADHD reflect, to a significant extent, the behavioral outcome of being unable to maintain a focus of attention on information within working memory while simultaneously dividing attention among multiple, on-going events and social cues occurring within the environment. Central executive deficits impacted social problems through both inattentive and impulsive-hyperactive symptoms, whereas the subsidiary phonological and visuospatial storage/rehearsal systems demonstrated a more limited yet distinct relationship with children’s social problems.     

Age-of-Onset or Behavioral Sub-Types? A Prospective Comparison of Two Approaches to Characterizing the Heterogeneity within Antisocial Behavior

There are two common approaches to sub-typing the well-documented heterogeneity within antisocial behavior: age-of-onset (i.e., childhood-onset versus adolescence-onset; see Moffitt 1993) and behavioral (i.e., physical aggression versus non-aggressive rule-breaking). These approaches appear to be associated, such that aggression is more characteristic of childhood-onset antisocial behavior whereas rule-breaking is linked to both child- and adolescence-onset antisocial behavior. However, it remains unclear which approach, if either, better explains the heterogeneity within antisocial behavior. We examined this question in a prospective sample of male twins, assessed at the ages of 11, 14, 17, and 24 years. Although the age-of-onset subtypes predicted adult antisocial behavior in the expected direction when analyzed alone, this association dissipated once we controlled for aggression and rule-breaking. Such findings suggest that the behavioral sub-types of antisocial behavior may be a stronger predictor of later antisocial outcomes than is its age-of-onset.     

Bayesian Fundamentalism or Enlightenment? On the explanatory status and theoretical contributions of Bayesian models of cognition

The prominence of Bayesian modeling of cognition has increased recently largely because of mathematical advances in specifying and deriving predictions from complex probabilistic models. Much of this research aims to demonstrate that cognitive behavior can be explained from rational principles alone, without recourse to psychological or neurological processes and representations. We note commonalities between this rational approach and other movements in psychology - namely, Behaviorism and evolutionary psychology - that set aside mechanistic explanations or make use of optimality assumptions. Through these comparisons, we identify a number of challenges that limit the rational program's potential contribution to psychological theory. Specifically, rational Bayesian models are significantly unconstrained, both because they are uninformed by a wide range of process-level data and because their assumptions about the environment are generally not grounded in empirical measurement. The psychological implications of most Bayesian models are also unclear. Bayesian inference itself is conceptually trivial, but strong assumptions are often embedded in the hypothesis sets and the approximation algorithms used to derive model predictions, without a clear delineation between psychological commitments and implementational details. Comparing multiple Bayesian models of the same task is rare, as is the realization that many Bayesian models recapitulate existing (mechanistic level) theories. Despite the expressive power of current Bayesian models, we argue they must be developed in conjunction with mechanistic considerations to offer substantive explanations of cognition. We lay out several means for such an integration, which take into account the representations on which Bayesian inference operates, as well as the algorithms and heuristics that carry it out. We argue this unification will better facilitate lasting contributions to psychological theory, avoiding the pitfalls that have plagued previous theoretical movements.     

Learning associations between action and perception: effects of incompatible training on body part and spatial priming

Observation of another person executing an action primes the same action in the observer's motor system. Recent evidence has shown that these priming effects are flexible, where training of new associations, such as making a foot response when viewing a moving hand, can reduce standard action priming effects (Gillmeister, Catmur, Liepelt, Brass, & Heyes, 2008). Previously, these effects were obtained after explicit learning tasks in which the trained action was cued by the content of a visual stimulus. Here we report similar learning processes in an implicit task in which the participant's action is self-selected, and subsequent visual effects are determined by the nature of that action. Importantly, we show that these learning processes are specific to associations between actions and viewed body parts, in that incompatible spatial training did not influence body part or spatial priming effects. Our results are consistent with models of visuomotor learning that place particular emphasis on the repeated experience of watching oneself perform an action.