Cumulative risk, maternal responsiveness, and allostatic load among young adolescents

The purpose of this study was to examine the impact of cumulative risk exposure in concert with maternal responsiveness on physiological indicators of chronic stress in children and youth. Middle-school children exposed to greater accumulated psychosocial (e.g., family turmoil, poverty) and physical (e.g., crowding, substandard housing) risk factors manifested higher levels of allostatic load, a physiological marker of cumulative wear and tear on the body caused by the mobilization of multiple, physiological response systems. This effect was longitudinal, residualizing allostatic load 3-4 years earlier when the youth were in elementary school. This effect, however, occurred only among adolescents with mothers low in responsiveness. Cumulative risk was also associated with dynamic cardiovascular processes in response to an acute stressor (mental arithmetic). Higher risk was associated with muted reactivity and slower, less efficient recovery in blood pressure. These dynamic cardiovascular effects occurred irrespective of maternal responsiveness.     

The probability of causal conditionals

Conditionals in natural language are central to reasoning and decision making. A theoretical proposal called the Ramsey test implies the conditional probability hypothesis: that the subjective probability of a natural language conditional, P(if p then q), is the conditional subjective probability, P(q/p). We report three experiments on causal indicative conditionals and related counterfactuals that support this hypothesis. We measured the probabilities people assigned to truth table cases, P(pq), P(p notq), P( notpq) and P( notp notq). From these ratings, we computed three independent predictors, P(p), P(q/p) and P(q/ notp), that we then entered into a regression equation with judged P(if p then q) as the dependent variable. In line with the conditional probability hypothesis, P(q/p) was by far the strongest predictor in our experiments. This result is inconsistent with the claim that causal conditionals are the material conditionals of elementary logic. Instead, it supports the Ramsey test hypothesis, implying that common processes underlie the use of conditionals in reasoning and judgments of conditional probability in decision making.     

Interference by process, not content, determines semantic auditory distraction

Distraction by irrelevant background sound of visually-based cognitive tasks illustrates the vulnerability of attentional selectivity across modalities. Four experiments centred on auditory distraction during tests of memory for visually-presented semantic information. Meaningful irrelevant speech disrupted the free recall of semantic category-exemplars more than meaningless irrelevant sound (Experiment 1). This effect was exacerbated when the irrelevant speech was semantically related to the to-be-remembered material (Experiment 2). Importantly, however, these effects of meaningfulness and semantic relatedness were shown to arise only when instructions emphasized recall by category rather than by serial order (Experiments 3 and 4). The results favor a process-oriented, rather than a structural, approach to the breakdown of attentional selectivity and forgetting: performance is impaired by the similarity of process brought to bear on the relevant and irrelevant material, not the similarity in item content.     

Preparing for Year 12 examinations: Predictors of psychological distress and sleep

This study examined the influence of protective factors on psychological distress and sleep among Year 12 students 1 month prior to their externally assessed examinations. The sample included 195 Year 12 students who were to sit for at least one examination. Students completed the Adolescent Resilience Questionnaire, a measure of subjective stress, the Depression Anxiety and Stress Scales – 21, and measures of sleep. A sizeable minority of students reported high levels of subjective stress, severe symptoms of depression, anxiety and stress, and very inadequate sleep. Freedom from negative cognitions was the factor most strongly associated with protection from psychological distress. None of the factors protected against inadequate sleep. Results showed few gender differences. The findings validate popular concern about the wellbeing of Year 12 students. They also confirm that protective factors do not provide equal protection for all individuals against all adverse outcomes.     

What causes auditory distraction?

The role of separating task-relevant from task-irrelevant aspects of the environment is typically assigned to the executive functioning of working memory. However, pervasive aspects of auditory distraction have been shown to be unrelated to working memory capacity in a range of studies of individual differences. We measured individual differences in global pattern matching and deliberate recoding of auditory sequences, and showed that, although deliberate processing was related to short-term memory performance, it did not predict the extent to which that performance was disrupted by task-irrelevant sound. Individual differences in global sequence processing were, however, positively related to the degree to which auditory distraction occurred. We argue that much auditory distraction, rather than being a negative function of working memory capacity, is in fact a positive function of the acuity of obligatory auditory processing.     

Quantity judgments of sequentially presented food items by capuchin monkeys (Cebus apella)

Recent assessments have shown that capuchin monkeys, like chimpanzees and other Old World primate species, are sensitive to quantitative differences between sets of visible stimuli. In the present study, we examined capuchins’ performance in a more sophisticated quantity judgment task that required the ability to form representations of food quantities while viewing the quantities only one piece at a time. In three experiments, we presented monkeys with the choice between two sets of discrete homogeneous food items and allowed the monkeys to consume the set of their choice. In Experiments 1 and 2, monkeys compared an entirely visible food set to a second set, presented item-by-item into an opaque container. All monkeys exhibited high accuracy in choosing the larger set, even when the entirely visible set was presented last, preventing the use of one-to-one item correspondence to compare quantities. In Experiment 3, monkeys compared two sets that were each presented item-by-item into opaque containers, but at different rates to control for temporal cues. Some monkeys performed well in this experiment, though others exhibited near-chance performance, suggesting that this species’ ability to form representations of food quantities may be limited compared to previously tested species such as chimpanzees. Overall, these findings support the analog magnitude model of quantity representation as an explanation for capuchin monkeys’ quantification of sequentially presented food items.

Seeking an ethical and legal way of procuring transplantable organs from the dying without further attempts to redefine human death

Because complex organs taken from unequivocally dead people are not suitable for transplantation, human death has been redefined so that it can be certified at some earlier stage in the dying process and thereby make viable organs available without legal problems. Redefinitions based on concepts of "brain death" have underpinned transplant practice for many years although those concepts have never found universal philosophical acceptance. Neither is there consensus about the clinical tests which have been held sufficient to diagnose the irreversible cessation of all brain function – or as much of it as is deemed relevant – while the body remains alive.     

Commentary on Baddeley and Larsen (2007). The phonological store abandoned

Baddeley and Larsen (2007) argue that a number of key findings reported by Jones, Macken, and Nicholls (2004) and Jones, Hughes, and Macken (2006) pointing to shortcomings of the phonological store construct arise from the store being abandoned with long lists. In our rejoinder we point out that Baddeley and Larsen use a procedure in which retrieval from the supposed phonological storage would not--according to their own theory--have been possible, and we present theoretical, empirical, and logical problems with their "store abandonment" argument and highlight a number of difficulties associated with the interpretation of suffix and prefix effects. We conclude that our data are still problematic for the phonological store construct and suggest that a reformulation of short-term memory theory needs to embody (or indeed focus exclusively upon) perceptual and effector systems rather than bespoke storage modules.