An investigation of DIF mechanisms in the context of differential testlet effects

This study investigated differential item functioning (DIF) mechanisms in the context of differential testlet effects across subgroups. Specifically, we investigated DIF manifestations when the stochastic ordering assumption on the nuisance dimension in a testlet does not hold. DIF hypotheses were formulated analytically using a parametric marginal item response function approach and compared with empirical DIF results from a unidimensional item response theory approach. The comparisons were made in terms of type of DIF (uniform or non‐uniform) and direction (whether the focal or reference group was advantaged). In general, the DIF hypotheses were supported by the empirical results, showing the usefulness of the parametric approach in explaining DIF mechanisms. Both analytical predictions of DIF and the empirical results provide insights into conditions where a particular type of DIF becomes dominant in a specific DIF direction, which is useful for the study of DIF causes.     

Cognitive disruption and altered hippocampus synaptic function in Reelin haploinsufficient mice

The heterozygote reeler mouse (HRM) shows many neuroanatomical and biochemical features that are also present in some human cognitive disorders, such as schizophrenia. In the present study, hippocampal dependent plasticity and cognitive function of the HRM were characterized in detail in an attempt to reveal phenotypic functional differences that result from Reelin haploinsufficiency. The HRM and wild type mice show similar levels of overall activity, coordination, thermal nociception, startle responses, and anxiety-like behavior. In addition, both genotypes show similar shock threshold, identical cued freezing behavior and comparable spatial learning in Morris water maze tasks. However, a significant reduction in contextual fear conditioned learning was observed in the HRM. Electrophysiological studies in hippocampal CA1 synapses revealed a plethora of differences between genotypes. The HRM exhibits reduced field excitatory postsynaptic potentials in responses to similar synaptic inputs, lowered paired pulse facilitation ratio and impaired long-term depression and tetanus-induced long-term potentiation (LTP). Also, deficits were detected in LTP elicited by theta burst stimulation or by a whole cell pairing protocol. These physiologic differences could not be accounted for by changes in the overall amount of glutamate receptor subunits. In addition, it was determined that network-driven excitatory and inhibitory activities recorded in CA1 pyramidal neurons showed that the HRM had comparable amplitude and frequency of spontaneous excitatory postsynaptic currents, but a marked reduction in spontaneous inhibitory postsynaptic currents. Thus, the HRM exhibits a specific hippocampal-dependent learning deficit accompanied with a pronounced impairment of hippocampal plasticity and functional inhibitory innervation.     

What is the role of mothers in the acquisition of termite-fishing behaviors in wild chimpanzees (Pan troglodytes schweinfurthii)?

This paper explores the role of maternal influences on the acquisition of a tool-using task in wild chimpanzees (Pan troglodytes schweinfurthii) in order to build on and complement previous work done in captivity. Young chimpanzees show a long period of offspring dependency on mothers and it is during this period that offspring learn several important skills, especially how to and on what to forage. At Gombe National Park, one skill that is acquired during dependency is termite-fishing, a complex behavior that involves inserting a tool made from the surrounding vegetation into a termite mound and extracting the termites that attack and cling to the tool. All chimpanzees observed at Gombe have acquired the termite-fishing skill by the age of 5.5 years. Since the mother is the primary source of information throughout this time period, I investigated the influence of mothers' individual termite-fishing characteristics on their offsprings' speed of acquisition and proficiency at the skill once acquired. Mother's time spent alone or with maternal family members, which is highly correlated to time spent termite-fishing, was positively correlated to offspring's acquisition of critical elements of the skill. I also investigated the specific types of social interactions that occur between mothers and offspring at the termite mound and found that mothers are highly tolerant to offspring, even when the behavior of the offspring may disrupt the termite-fishing attempt. However, no active facilitation by mothers of offsprings' attempts were observed. Electronic Supplementary Material Electronic supplementary material Supplementary material is available for this article at http://dx.doi.org/10.1007/s10071-005-0002-7 and accessible for authorised users.     

Taking the task seriously: reflections on measures of color acquisition

The experiments described in the lead articles by Kowalski and Zimiles and by O'Hanlon and Roberson examine factors that lead to color term acquisition. These experiments touch on the debate regarding the relative contributions of language and concepts in word learning. In this reflection, we examine how conclusions concerning the debate depend deeply on the particular task presented to children, and we propose an alternative approach to studying color term acquisition.     

Novel labels support 10-month-olds’ attention to novel objects

What is the source of the mutual exclusivity bias whereby infants map novel labels onto novel objects? In an intermodal preferential looking task, we found that novel labels support 10-month-olds’ attention to a novel object over a familiar object. In contrast, familiar labels and a neutral phrase gradually reduced attention to a novel object. Markman (1989, 1990) argued that infants must recall the name of a familiar object to exclude it as the referent of a novel label. We argue that 10-month-olds’ attention is guided by the novelty of objects and labels rather than knowledge of the names for familiar objects. Mutual exclusivity, as a language-specific bias, might emerge from a more general constraint on attention and learning.     

Estimation and visualization of confusability matrices from adaptive measurement data

We present a simple but effective method based on Luce’s choice axiom [Luce, R.D. (1959). Individual choice behavior: A theoretical analysis. New York: John Wiley & Sons] for consistent estimation of the pairwise confusabilities of items in a multiple-choice recognition task with arbitrarily chosen choice-sets. The method combines the exact (non-asymptotic) Bayesian way of assessing uncertainty with the unbiasedness emphasized in the classical frequentist approach.We apply the method to data collected using an adaptive computer game designed for prevention of reading disability. A player’s estimated confusability of phonemes (or more accurately, phoneme-grapheme connections) and larger units of language is visualized in an easily understood way with color cues and explicit indication of the accuracy of the estimates. Visualization of learning-related changes in the player’s performance is considered.The empirical validity of the choice axiom is evaluated using the game data itself. The axiom appears to hold reasonably well although a small systematic violation is observable for the smallest choice-set sizes.     

The exponential learning equation as a function of successful trials results in sigmoid performance

While the exponential learning equation, indicating a gradually diminishing improvement, is one of the standard equations to describe learning, a sigmoid behavior with initially increasing then decreasing improvement has also been suggested. Here we show that the sigmoid behavior is mathematically derived from the standard exponential equation when the independent variable of the equation is restricted to the successful trials alone. It is suggested that for tasks promoting success-based learning, performance is better described by the derived sigmoid curve.     

A Recess Evaluation with the Players: Taking Steps Toward Participatory Action Research

This qualitative study, part of a Canadian national study of fathers’ involvement, opened up First Nations and Métis fathering as a new area of inquiry. Conversational interviews with 80 Indigenous fathers illuminated the socio-historical conditions that have shaped Indigenous men’s experiences of learning to be a father and becoming a man in the context of changing gender relationships and the regeneration of circles of care. Indigenous fathers’ experiences unfold in a socio-historical context fraught with difficulties. However, the study findings suggest cultural strengths and sources of resilience unseen in research and community programs driven by Euro-western perspectives. This research can inform efforts to reduce systemic barriers and reconstitute positive father involvement following disrupted intergenerational transmission of fathering in Canada and elsewhere.     

Physical discipline,escalation, and child abuse potential: psychometric evidence for the Analog Parenting Task

Data from three studies provide new evidence to support the validity of the Analog Parenting Task (APT) as an instrument to assess risk for harsh, physically aggressive parenting. In this series of studies, there was a strong association between APT scores of expected use and escalation of discipline strategies and self‐reported disciplinary attitudes. APT scores were also associated with physical abuse potential as assessed by both a well‐established measure of child abuse potential (Child Abuse Potential Inventory) and another instrument designed specifically for use in pre‐parent populations (e.g., Adult–Adolescent Parenting Inventory‐2). This study provides new psychometric evidence to support the use of the APT to assess harsh parenting. Additionally, these data highlight the connection between acceptance and use of physical disciplinary strategies, propensity for disciplinary escalation, and risk for abuse perpetration. The findings are discussed in the context of Milner's Social Information Processing model [Milner, 2003] of abuse, which suggests that parental selection of disciplinary responding and the monitoring of disciplinary responding are key events in the disciplinary process. The APT may prove a useful adjunct to more commonly used self‐report measures to allow for multimethod assessment of risk for punitive parenting. Aggr. Behav. 36:251–260, 2010. © 2010 Wiley‐Liss, Inc.     

Familiar and unfamiliar face recognition: A review

Since the 1970s there has been a continuing interest in how people recognise familiar faces (Bruce, 1979 Bruce, V. 1979. Searching for politicians: An information processing approach to face recognition. Quarterly Journal of Experimental Psychology, 31: 373–395. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; Ellis, 1975 Ellis, H.D. 1975. Recognising faces. British Journal of Psychology, 66: 409–426. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). This work has complemented investigations of how unfamiliar faces are processed and the findings from these two strands of research have given rise to accounts that propose qualitatively different forms of representation for familiar and unfamiliar faces. Evidence to suggest that we process familiar and unfamiliar faces in different ways is available from cognitive neuropsychology, brain scanning, and psychophysics. However, in this review we focus on the evidence, available from experimental investigations of how people recognise faces, for different types of representation existing for each type of face. Factors affecting recognition are evaluated in terms of how they apply to familiar and unfamiliar faces and categorised according to the nature of their impact. In the final section this evidence, along with recent advances in the field, is used to explore the way in which unfamiliar faces may become familiar and the factors that may be important for the development of familiar face representations.