Immediate postsession feeding reduces operant responding in rats

Three experiments investigated the effects of immediate and delayed postsession feeding on progressive-ratio and variable-interval schedule performance in rats. During Experiments 1 and 2, immediate postsession feeding decreased the breakpoint, or largest completed ratio, under progressive-ratio schedules. Experiment 3 was conducted to extend the results of the first two experiments to responding maintained by variable-interval schedules with different session lengths (15 and 60 min). Response rates decreased in all 4 subjects when postsession feeding immediately followed a 15-min session and in 3 of 4 subjects when postsession feeding immediately followed a 60-min session. The implications of this research are twofold: (1) The functional context in which within-session reinforcers are embedded extends outside the experimental chamber, and (2) supplemental postsession feedings should be sufficiently delayed from the end of a session to avoid weakening operant behavior in the experimental sessions.     

Distinct contributions of the caudate nucleus, rostral prefrontal cortex, and parietal cortex to the execution of instructed tasks

When we behave according to rules and instructions, our brains interpret abstract representations of what to do and transform them into actual behavior. In order to investigate the neural mechanisms behind this process, we devised an fMRI experiment that explicitly isolated rule interpretation from rule encoding and execution. Our results showed that a specific network of regions (including the left rostral prefrontal cortex, the caudate nucleus, and the bilateral posterior parietal cortices) is responsible for translating rules into executable form. An analysis of activation patterns across conditions revealed that the posterior parietal cortices represent a mental template for the task to perform, that the inferior parietal gyrus and the caudate nucleus are responsible for instantiating the template in the proper context, and that the left rostral prefrontal cortex integrates information across complex relationships.     

Agonistic and antagonistic interaction in speed/accuracy tradeoff: A delta-lognormal perspective

This paper reports the results of a model-based analysis of movements gathered in a 4 × 4 experimental design of speed/accuracy tradeoffs with variable target distances and width. Our study was performed on a large (120 participants) and varied sample (both genders, wide age range, various health conditions). The delta-lognormal equation was used for data modeling to investigate the interaction between the output of the agonist and the antagonist neuromuscular systems. Empirical observations show that the subjects must correlate more tightly the impulse commands sent to both neuromuscular systems in order to achieve good performances as the difficulty of the task increases whereas the correlation in the timing of the neuromuscular action co-varies with the size of the geometrical properties of the task. These new phenomena are discussed under the paradigm provided by the Kinematic Theory and new research hypotheses are proposed for further investigation of the speed/accuracy tradeoffs.     

Mothers’ Experiences of Parent-Reported and Video-Recorded Observational Assessments

Rigorous evaluation of early childhood interventions requires accurate and efficient measurement. Researchers commonly use parent-reported surveys or direct observations; both of which have inherent strengths and limitations. Existing attempts to understand the correspondence between these methods have been primarily quantitative in design. Little is known about parents’ unique, subjective experiences of parent-reported surveys and direct parent-child observations. In this paper, we describe the experiences of ten mothers of children aged 24 months, recruited from a randomised controlled trial of a nurse home visiting program for mothers at risk of experiencing social adversity. After completing both a survey and video-recorded parent-child observation, mothers participated in in-depth semi-structured interviews which were analysed thematically. Mothers voiced concerns about how researchers may view their parenting skills, and their child’s behaviour and development. Contrary to previous quantitative evidence, mothers reported parent and child behavioural change, which they attributed to the researcher’s presence. Mothers described how the structured requirements of the observation contributed to forced and unnatural interactions. The survey was viewed as a welcome opportunity to reflect on parenting skills, the parent-child relationship and the child’s development. Mothers identified practical strategies for minimising parent-child discomfort during video-recorded observations, such as the researcher averting their gaze or stepping out of the room. We highlight opportunities for enhanced data validity in research and clinical settings, strengthened participant engagement, and minimisation of participant discomfort. Given the exploratory nature of this study, we do not claim that results are necessarily generalisable to other parent or general populations. Further research is warranted to build the evidence regarding parent participation in early childhood research.     

Conditioned taste aversions: From poisons to pain to drugs of abuse

Learning what to eat and what not to eat is fundamental to our well-being, quality of life, and survival. In particular, the acquisition of conditioned taste aversions (CTAs) protects all animals (including humans) against ingesting foods that contain poisons or toxins. Counterintuitively, CTAs can also develop in situations in which we know with absolute certainty that the food did not cause the subsequent aversive systemic effect. Recent nonhuman animal research, analyzing palatability shifts, has indicated that a wider range of stimuli than has been traditionally acknowledged can induce CTAs. This article integrates these new findings with a reappraisal of some known characteristics of CTA and presents a novel conceptual analysis that is broader and more comprehensive than previous accounts of CTA learning.     

My face or yours? Event-related potential correlates of self-face processing

The neural basis of self-recognition is mainly studied using brain-imaging techniques which reveal much about the localization of self-processing in the brain. There are comparatively few studies using EEG which allow us to study the time course of self-recognition. In this study, participants monitored a sequence of images, including 20 distinct images of their own face, a friend’s face and a stranger’s face articulating different speech sounds, while EEG was recorded from 64 scalp electrodes. Differences in the ERP waveforms were observed very early on, with increased N170 and VPP amplitude to self relative to both friend and stranger measured over posterior and fronto-central sites, respectively. This ‘self effect’ was also marked at ∼250 ms where P2/N2 amplitude was significantly reduced for self-faces. By comparison, differences between friend and stranger faces did not emerge until 250 ms and beyond, where a more conventional ‘familiarity effect’ was observed. The data also point to a ‘less lateralized’ representation of self over posterior sites. These findings are consistent with both behavioral and fMRI studies which suggest that self-face processing is ‘special’ and are discussed with reference to EEG studies of face processing.     

Effect of Item Level Social Desirability on Factor Structure Stability

This study examined the effect of item‐level social desirability as a threat to construct validity for both a five‐factor biodata and personality inventory. Seven hundred and five participants were randomly assigned to either an Answer Honestly or Faking condition. All participants completed a biodata inventory and a NEO‐Five‐Factor Inventory. Both inventories' items were divided by low/high social desirability value (SDV) scores and grouped together. Differences between samples' covariance matrices and factor structure fit were then analyzed. It was predicted that items grouped by low SDV compared with those grouped by high SDV, would result in smaller changes in covariance matrices across conditions, and more closely retain factor structures consistent with the Five‐Factor Model. Although the results of this study supported predictions that covariance matrices changed less for low‐SDV items, overall results indicate that item‐level social desirability did not degrade the factor structure.     

Interaction between the development of postural control and the executive function of attention

The authors examined the interaction between the development of postural control and the development of the executive function of attention in 13 children and 6 adults in dual-task conditions. Participants performed an attentionally demanding cognitive task and a postural task simultaneously. The authors equalized the attentional load of the cognitive task across age groups. Comparative changes in the center of pressure in dual- and single-task conditions indicated that dual tasks interfered with postural performance in the wide stance (WS) and the modified Romberg stance (RS). Children at 4-6 years of age (but not children at ages 7-12 years of age or adults) experienced postural control interference in both stance positions, but interference was greater in the RS (p = .018). For all participants, cognitive task performance in RS was unchanged from that in WS. The knowledge gained from the results of this study will contribute to the design and implementation of academic and preacademic programming for young children. Their performance of an intentionally demanding cognitive task would be enhanced by the provision of appropriately sized desks and chairs or their use of an alternate, less demanding position.     

Training Appraisees to Participate in Appraisal: Effects on Appraisers and Appraisees

This study examined the role of behavior modeling training (BMT) in enhancing appraisee participation during a performance appraisal discussion. In addition, the study examined the effects of enhanced participation on appraisee and appraiser perceptions toward several appraisal outcome variables; in particular, the fairness and accuracy of performance appraisal were of interest. The experimental design was a 2 × 3 completely crossed factorial design consisting of two levels of training (behavior modeling vs. lecture/discussion) and three levels of bogus evaluation feedback (low, neutral, and high). A series of multivariate and univariate comparisons were used to test the hypothesized outcomes. The findings suggest that appraisers exposed to the BMT group perceived appraisees as more proactive and better performers and, in addition, reported liking the appraisees more, and perceiving the appraisal process as more fair. The study also found support for the egocentric bias in perceived outcome fairness: appraisees in both training conditions who received a high evaluation perceived the appraisal evaluation as more fair than appraisees who received a low evaluation. In addition, the study found that favorable evaluations were also perceived as being more accurate. The results of the study are discussed in terms of procedural justice theory and related research examining the role of performance feedback on both the appraisee and the appraiser. Suggestions for future research in the areas of behavior modeling, voice-giving (high-input) procedures, and procedural justice are discussed.