How to build a brain: from function to implementation

To have a fully integrated understanding of neurobiological systems, we must address two fundamental questions: 1. What do brains do (what is their function)? and 2. How do brains do whatever it is that they do (how is that function implemented)? I begin by arguing that these questions are necessarily inter-related. Thus, addressing one without consideration of an answer to the other, as is often done, is a mistake. I then describe what I take to be the best available approach to addressing both questions. Specifically, to address 2, I adopt the Neural Engineering Framework (NEF) of Eliasmith &; Anderson [Neural engineering: Computation representation and dynamics in neurobiological systems. Cambridge, MA: MIT Press, 2003] which identifies implementational principles for neural models. To address 1, I suggest that adopting statistical modeling methods for perception and action will be functionally sufficient for capturing biological behavior. I show how these two answers will be mutually constraining, since the process of model selection for the statistical method in this approach can be informed by known anatomical and physiological properties of the brain, captured by the NEF. Similarly, the application of the NEF must be informed by functional hypotheses, captured by the statistical modeling approach.     

Is Theory of Mind Understanding Impaired in Males with Fragile X Syndrome?

Males with fragile X syndrome (FXS) have difficulties with social interaction and many show autistic features. This study examined whether the social deficits characteristic of FXS are associated with theory of mind difficulties. Two groups of boys with FXS participated: a group with few autistic features and a group with many autistic features. An intellectual disability control group also participated. In addition to using standard theory of mind tasks, new techniques were used that were able to separate out the various processing demands of the task (e.g., memory, inhibitory control). Overall, the findings indicate that both groups of boys with FXS have difficulty with theory of mind tasks compared to an intellectual disability control group. However, both groups with FXS also performed worse on comparison trials that required working memory but not theory of mind. Theory of mind difficulties are likely to be an important aspect of the FXS clinical profile, but are most likely the result from a more basic difficulty with working memory.     

The effects of anxiety upon attention allocation to affective stimuli

Pictures of emotionally aversive, neutral, and pleasant scenes were presented for 500 ms, followed by a probe presented in the same location (valid trials) or an alternate location (invalid trials) as the picture. Response-times to the probes were recorded in low (N=20) and high (N=27) trait anxious participants. Results revealed an overall negative cue validity effect of shorter reaction times (RTs) on invalid than valid trials, suggestive of an inhibition of return effect. Moreover, high trait anxious females showed a reduced negative cue validity effect for aversive pictures in comparison with neutral and pleasant pictures, suggestive of selective interference by the unpleasant material. By contrast, low trait anxious females showed an enhanced negative cue validity effect for aversive pictures relative to neutral and pleasant pictures, suggestive of attentional avoidance of the aversive content. The emotional content of picture cues did not significantly affect RTs in males, regardless of anxiety status. The results suggest that biased attention processes for aversive stimuli may contribute to the greater female propensity for anxiety disorders.     

Vicarious learning and the development of fears in childhood

Vicarious learning has long been assumed to be an indirect pathway to fear; however, there is only retrospective evidence that children acquire fears in this way. In two experiments, children (aged 7-9 years) were exposed to pictures of novel animals paired with pictures of either scared, happy or no facial expressions to see the impact on their fear cognitions and avoidance behavior about the animals. In Experiment 1, directly (self-report) and indirectly measured (affective priming) fear attitudes towards the animals changed congruent with the facial expressions with which these were paired. The indirectly measured fear beliefs persisted up to 3 months. Experiment 2 showed that children took significantly longer to approach a box they believed to contain an animal they had previously seen paired with scared faces. These results support theories of fear acquisition that suppose that vicarious learning affects cognitive and behavioral fear emotion, and suggest possibilities for interventions to weaken fear acquired in this way.     

Variation in coordination of a discrete multiarticular action as a function of skill level

The authors investigated coordination modes that emerged as a function of the interaction between skill level and task constraints in a multiarticular kicking action. Five skilled, 5 intermediate, and 5 novice participants attempted to satisfy specific height and accuracy constraints in kicking a ball over a barrier. Skilled and intermediate groups demonstrated a functional coordination mode involving less joint involvement at the proximal joints and greater joint involvement at distal joints, mimicking a chip-like action in soccer. Conversely, the novice group tended to produce larger ranges of motion throughout the kicking limb in a driving-like kicking action. Key differences were also found for task outcome scores, joint angle-angle relations, and ball-trajectory plots between the skilled and intermediate groups and the novice group. Findings from this study demonstrated that joint involvement during this discrete multiarticular action is a function of skill level and task constraints rather than a consequence of a global freezing-freeing strategy suggested in some previous research. The authors also highlight the merit of using a model of the acquisition of coordination in examining how coordination modes for multiarticular actions differ as a function of skill.     

Introducing the Concepts of “Positions,” “Space,” and “Worlds”: Seeing Human Being and Becoming—and Religion—in New Ways

Theories of psychological development, however diverse, often express common underlying ontological-epistemological commitments shaped by the legacies of Descartes, Newton, and Kant. Three related psychoanalytic concepts—“positions,” “space,” and “worlds”—individually and collectively sketch the contours of a different way of construing human being and becoming—a way that departs from these legacies. Implications for the study of religion of this “different way” are examined.     

The reduction of sensory pleasure to desire

One of the leading approaches to the nature of sensory pleasure reduces it to desire: roughly, a sensation qualifies as a sensation of pleasure just in case its subject wants to be feeling it. This approach is, in my view, correct, but it has never been formulated quite right; and it needs to defended against some compelling arguments. Thus the purpose of this paper is to discover the most defensible formulation of this rough idea, and to defend it against the most interesting objections.     

Memory for emotionally neutral information in posttraumatic stress disorder: A meta-analytic investigation

Studies have come to conflicting conclusions about whether posttraumatic stress disorder (PTSD) is associated with poorer memory for emotionally neutral information. The authors report a meta-analysis of 27 studies that investigated verbal and/or visual memory in samples with PTSD and healthy controls. The results indicated that the association between PTSD and memory impairment appears to be robust, small to moderate in size, and stronger for verbal than for visual memory. Effect sizes did not vary according to whether recall was immediate or delayed. The association is found in both civilian and military samples and cannot be readily explained as being due to the use of nontraumatized healthy control groups or concurrent head injury. The findings are placed in the context of recent neurobiological and experimental cognitive research.     

Choice strategies in multiple-cue probability learning

Choice strategies for selecting among outcomes in multiple-cue probability learning were investigated using a simulated medical diagnosis task. Expected choice probabilities (the proportion of times each outcome was selected given each cue pattern) under alternative choice strategies were constructed from corresponding observed judged probabilities (of each outcome given each cue pattern) and compared with observed choice probabilities. Most of the participants were inferred to have responded by using a deterministic strategy, in which the outcome with the higher judged probability is consistently chosen, rather than a probabilistic strategy, in which an outcome is chosen with a probability equal to its judged probability. Extended practice in the learning environment did not affect choice strategy selection, contrary to reports from previous studies, results of which may instead be attributable to changes with practice in the variability and extremity of the perceived probabilities on which the choices were based.     

When Women Become More Hostilely Sexist toward their Gender: The System-Justifying Effect of Benevolent Sexism

Two longitudinal studies examined the system-justifying effect of women’s benevolent sexist ideology in New Zealand female undergraduate samples. Women’s endorsement of benevolent sexism predicted longitudinal changes in hostile sexist attitudes toward their gender over 6-month (study 1; n?=?117) and 12-month (study 2; n?=?76) periods. Consistent with Ambivalent Sexism Theory, these findings indicate that women’s endorsement of benevolent sexism disarms resistance to, and increases their endorsement of, more hostile forms of sexism directed toward their gender. However, the disarming effect of benevolent sexism occurred only for women high in Right-Wing Authoritarianism (study 2), suggesting that threat-driven authoritarian motivations for collective security and social cohesion cause women to actively participate in an ideological system that perpetuates gender inequality.