Failure to replicate a QTL association between a DNA marker identified by EST00083 and IQ

In a paper published in this journal, a possible QTL association was reported between general cognitive ability and a marker, identified by an expressed sequence tag, EST00083 (Skuder et al., 1995). In two small samples, the frequency of the common allele of this DNA marker, which was shown to be in the threonine transfer RNA gene in mitochondrial DNA, was significantly greater in a high-IQ group than in a low-IQ group. As part of the ongoing IQ QTL Project (Plomin et al., 1995), we have attempted to replicate this QTL association. First, we found that the QTL association remained significant when we compared 51 high- and 51 -average IQ subjects, drawn in part from the samples used in the previous report. However, when we examined the association in new samples of 40 extremely high-IQ subjects and 50 average-IQ subjects, the association did not replicate. This underlies the need for replication in case-control studies of allelic association.     

Objective and subjective bulimic episodes in the classification of bulimic-type eating disorders: Another nail in the coffin of a problematic distinction

We sought to further explore the validity of the distinction between objective bulimic episodes (OBEs) and subjective bulimic episodes (SBEs) in the study of bulimic-type eating disorders. Drawing on data obtained at the second, interview phase of a large-scale epidemiological study, we identified mutually exclusive subgroups of women with bulimic-type eating disorders who engaged in regular OBEs but not SBEs (n = 37) or regular SBEs but not OBEs (n = 52). These subgroups were compared on a wide range of outcomes, including socio-demographic characteristics, current levels of eating disorder psychopathology, general psychological distress and impairment in role functioning, current and lifetime impairment in quality of life specifically associated with an eating problem, (self)-recognition of an eating problem, health service utilization and use of psychotropic medication. The only difference between groups was that participants who reported regular OBEs were heavier than those who reported regular SBEs. The findings converge with those of previous research in suggesting that bulimic-type eating disorders characterized by regular SBEs, but not OBEs, do not differ in any clinically meaningful way from those characterized by regular OBEs, but not SBEs. Inclusion of bulimic-type eating disorders characterized by regular SBEs as a provisional category requiring further research in DSM-V appears warranted.     

The Ethics of Producing In Vitro Meat

The prospect of consumable meat produced in a laboratory setting without the need to raise and slaughter animals is both realistic and exciting. Not only could such in vitro meat become popular due to potential cost savings, but it also avoids many of the ethical and environmental problems with traditional meat productions. However, as with any new technology, in vitro meat is likely to face some detractors. We examine in detail three potential objections: 1) in vitro meat is disrespectful, either to nature or to animals; 2) it will reduce the number of happy animals in the world; and 3) it will open the door to cannibalism. While each objection has some attraction, we ultimately find that all can be overcome. The upshot is that in vitro meat production is generally permissible and, especially for ethical vegetarians, worth promoting.     

Profiling Movement and Gait Quality Characteristics in Pre-School Children

There is a dearth of suitable metrics capable of objectively quantifying motor competence. Further, objective movement quality characteristics during free play have not been investigated in pre-school children. The aims of this study were to characterize children's free play physical activity and investigate how gait quality characteristics cluster with free play in pre-school children (3–5 years old). Sixty-one children (39 boys; 4.3 ± 0.7 years, 1.04 ± 0.05 m, 17.8 ± 3.2 kg) completed the movement assessment battery for children and took part in free play while wearing an ankle- and hip-mounted accelerometer. Characteristics of movement quality were profiled using a clustering algorithm. Spearman's rho and the Mann-Whitney U tests were used to assess relationships between movement quality characteristics and motor competence classification differences in integrated acceleration and spectral purity, respectively. Significant differences were found between motor competency classifications for spectral purity and integrated acceleration (p < .001). Spectral purity was hierarchically clustered with motor competence and integrated acceleration. Significant positive correlations were found between spectral purity, integrated acceleration and motor competence (p < .001). This is the first study to report spectral purity in pre-school children and the results suggest that the underlying frequency component of movement is clustered with motor competence.     

Development and preliminary validation of the Paediatric Awareness Questionnaire for children and adolescents with traumatic brain injury

There is a lack of validated measures for assessing self-awareness of deficits after pediatric traumatic brain injury (TBI). The current study aimed to develop and examine the psychometric properties of the Paediatric Awareness Questionnaire (PAQ), and investigate factors related to self-awareness. The PAQ was administered to 32 children aged 8–16 years with mild to severe TBI (72% male, M age = 11.75, SD = 2.9), their parents, and treating clinicians, and to 32 age- and gender-matched typically developing controls and their parents. Children with TBI and their parents also completed the Knowledge of Injury Checklist (KIC), and parents completed the Depression Anxiety and Stress Scale 21. The PAQ was found to have fair to excellent (α = .79–.97) internal consistency for all versions across both groups and good concordance between parent and clinician total scores (ICC = .78). There was also evidence of convergent validity between the PAQ and KIC for both child (r = ?.45, p < .05) and parent ratings (r = ?.66, p < .001). Poorer self-awareness was significantly related to younger age at injury for the TBI group and lower parental education for the total sample. ANCOVA identified that children with TBI demonstrated significantly poorer awareness than controls after controlling for parental education. Children with TBI typically overestimated their functioning compared to their parents, whereas typically developing children tended to rate their functioning lower than their parents. These findings provide preliminary support for the reliability and validity of the PAQ for assessing self-awareness after pediatric TBI.     

Close interpersonal proximity modulates visuomotor processing of object affordances in shared,social space

Research suggests that the human brain codes manipulable objects as possibilities for action, or affordances, particularly objects close to the body. Near-body space is not only a zone for body-environment interaction but also is socially relevant, as we are driven to preserve our near-body, personal space from others. The current, novel study investigated how close proximity of a stranger modulates visuomotor processing of object affordances in shared, social space. Participants performed a behavioural object recognition task both alone and with a human confederate. All object images were in participants’ reachable space but appeared relatively closer to the participant or the confederate. Results revealed when participants were alone, objects in both locations produced an affordance congruency effect but when the confederate was present, only objects nearer the participant elicited the effect. Findings suggest space is divided between strangers to preserve independent near-body space boundaries, and in turn this process influences motor coding for stimuli within that social space. To demonstrate that this visuomotor modulation represents a social phenomenon, rather than a general, attentional effect, two subsequent experiments employed nonhuman joint conditions. Neither a small, Japanese, waving cat statue (Experiment 2) nor a metronome (Experiment 3) modulated the affordance effect as in Experiment 1. These findings suggest a truly social explanation of the key interaction from Experiment 1. This study represents an important step toward understanding object affordance processing in real-world, social contexts and has implications broadly across fields of social action and cognition, and body space representation.     

Fear Learning in Veterans With Combat-Related PTSD Is Linked to Anxiety Sensitivity: Evidence From Self-Report and Pupillometry

Several studies have observed heightened Pavlovian fear conditioning in PTSD. However, it is unclear how fear conditioning in PTSD is related to risk factors for the disorder, such as anxiety sensitivity. Fifty-one combat-exposed veterans (20 with PTSD, 31 without PTSD) completed a differential fear conditioning task in which one colored rectangle (CS +) predicted a loud scream (US), whereas a different colored rectangle (CS-) predicted no US. Veterans with PTSD were characterized by greater anxiety to the CS + but not the CS- during acquisition and extinction, and greater US expectancy during the CS + but not the CS- at extinction. Also, veterans with PTSD had greater pupil dilation to both CSs at extinction, but not at acquisition. Anxiety sensitivity was correlated with anxiety and US expectancy in response to the CS +, but not the CS-, at both acquisition and extinction, and also with pupil diameter to both the CS + and CS- at extinction. Nearly all of these relations held when covarying for PTSD symptoms and trait anxiety. These findings suggest that increased fear conditioning in PTSD may be related to elevated anxiety sensitivity.