Global, local, and graphical person-fit analysis using person-response functions

Person-fit statistics test whether the likelihood of a respondent's complete vector of item scores on a test is low given the hypothesized item response theory model. This binary information may be insufficient for diagnosing the cause of a misfitting item-score vector. The authors propose a comprehensive methodology for person-fit analysis in the context of nonparametric item response theory. The methodology (a) includes H. Van der Flier's (1982) global person-fit statistic U3 to make the binary decision about fit or misfit of a person's item-score vector, (b) uses kernel smoothing (J. O. Ramsay, 1991) to estimate the person-response function for the misfitting item-score vectors, and (c) evaluates unexpected trends in the person-response function using a new local person-fit statistic (W. H. M. Emons, 2003). An empirical data example shows how to use the methodology for practical person-fit analysis.     

Perceptual asymmetries are preserved in memory for highly familiar faces of self and friend

We investigated the effect of familiarity on people's perception of facial likeness by asking participants to choose which of two mirror-symmetric chimeric images (made from the left or right half of a photograph of a face) looked more like an original image. In separate trials the participants made this judgment for their own face and for the face of a close friend; half of them matched to a true image of the original and half matched to a mirror image of the original. In the case of matching to a friend's face presented in the familiar orientation, over 80% of participants chose the left-left composite to be a better likeness to the original, whereas only 62% showed the same left-side bias when matching to a mirror image. The difference is significant, and the result contrasts markedly with a second experiment where participants who were unfamiliar with the faces showed comparable left-side biases when matching to true or mirror reversed images. The result suggests that perceptual asymmetries are retained in our long-term memory for highly familiar faces. While matching to images of self also showed an effect of familiarity, the data in this condition show less evidence of perceptual asymmetry and are discussed in relation to recent research on the representation of one's own face.     

The recognition of reduced word forms

This article addresses the recognition of reduced word forms, which are frequent in casual speech. We describe two experiments on Dutch showing that listeners only recognize highly reduced forms well when these forms are presented in their full context and that the probability that a listener recognizes a word form in limited context is strongly correlated with the degree of reduction of the form. Moreover, we show that the effect of degree of reduction can only partly be interpreted as the effect of the intelligibility of the acoustic signal, which is negatively correlated with degree of reduction. We discuss the consequences of our findings for models of spoken word recognition and especially for the role that storage plays in these models.     

"Markov at the bat": a model of cognitive processing in baseball batters

Anecdotal evidence from players and coaches indicates that cognitive processing (e.g., expectations about the upcoming pitch) plays an important role in successful baseball batting, yet this aspect of hitting has not been investigated in detail. The present study provides experimental evidence that prior expectations significantly influence the timing of a baseball swing. A two–state Markov model was used to predict the effects of pitch sequence and pitch count on batting performance. The model is a hitting strategy of switching between expectancy states using a simple set of transition rules. In a simulated batting experiment, the model provided a good fit to the hitting performance of 6 experienced college baseball players, and the estimated model parameters were highly correlated with playing level.     

Project HOPE: Implementing Sensory Experiences for Suicide Prevention in a Native American Community

Suicide remains a significant problem for Native American populations; however, culturally appropriate interventions are lacking (Suicide Prevention Resource Center, 2011 Suicide Prevention Resource Center . ( 2011 ). Suicide Among American Indians/Alaska Natives. Retrieved from http://www.sprc.org/library/ai.an.facts.pdf  [Google Scholar]). Occupational therapy practitioners can aid in suicide prevention and intervention (American Occupational Therapy Association, 2005). This study presents a culturally appropriate program and research project following a community-based participatory research design that explores the impact of a sensory curriculum for suicide prevention on Native American youth. The perceptions of the young peoples' sensory experiences are explored. Evidence from the study demonstrates the value of exploring the use of occupational therapy intervention in Native American communities to address significant health concerns.     

Tool-use and the left hemisphere: What is lost in ideomotor apraxia?

Impaired tool related action in ideomotor apraxia is normally ascribed to loss of sensorimotor memories for habitual actions (engrams), but this account has not been tested against a hypothesis of a general deficit in representation of hand-object spatial relationships. Rapid reaching for familiar tools was compared with reaching for abstract objects in apraxic patients (N = 9) and in a control group with right hemisphere posterior stroke. The apraxic patients alone showed an impairment in rotating the wrist to correctly grasp an inverted tool but not when inverting the hand to avoid a barrier and grasp an abstract object, and the severity of the impairment in tool reaching correlated with pantomime of tool-use. A second experiment with two apraxic patients tested whether barrier avoidance was simply less spatially demanding than reaching for a tool. However, the patient with damage limited to the inferior parietal lobe still showed a selective problem for tools. These results demonstrate that some apraxic patients are selectively impaired in their interaction with familiar tools, and this cannot be explained by the demands of the task on postural or spatial representation. However, traditional engram theory cannot account for associated problems with imitation of novel actions nor the absence of any correlated deficit in recognition of the methods of grasp of common tools. A revised theory is presented which follows the dorsal and ventral streams model ( Milner & Goodale, 2008) and proposes preservation of motor control by the dorsal stream but impaired modulating input to it from the conceptual systems of the left temporal lobe.     

Bernstein's Theory of Movement Behavior: Historical Development and Contemporary Relevance

The traditional concept of cerebral dominance relies for support on the facts of handedness and the association of propositional speech with the leading hemisphere. This is regarded as evidence for specialization but not that the hemispheres are involved in an unchanging dominance relationship. The fact that the corpus callosum forms a bridge between the hemispheres means that they are not isolated units and that one may work through the other to control the functions of the limbs. Control however may be switched as the tasks demand the respective specializations of each hemisphere.     

Managing Retirement—Rethinking Links between Individual and Organization

Retirement represents an important life event in Western countries marking the transition from one life stage to another and the movement from being within to being outside the labour force. For employees, retirement might represent the border between organizational life and life outside the workplace. This border, though commonly thought of as fixed and distinct, is becoming more and more blurred. Organizations and organizational psychology have thus far largely ignored retirement as a relevant topic. However, the changing nature of retirement, as a consequence of demographic changes and developments in the labour market, means that we need to rethink our assumptions about retirement and to attempt to specify some of the missing links between individual and organizational perspectives on retirement. We will argue that retirement is not only an important event in the life of working individuals but has become an important issue for management. This article will discuss some individual retirement processes and possible impacts of retirement on the organization focusing, in particular, on the use of early retirement schemes as a management tool replacing traditional redundancies. It is suggested that these early retirement schemes neglect some basic aspects of individual and organizational retirement processes and are likely therefore in some cases to be less than effective. By describing a different model for managing retirement we aim to suggest how a better balance between individual and organizational needs can be achieved.     

Cultural and learning differences in the Judd illusion

In the present study, we examined whether individual differences in the perception of illusory Judd drawings point to variability in the pickup of informational variables. Two sources for these individual differences were addressed: culture and learning. East Asian (n = 24) and Western (n = 24) participants made perceptual judgments of the midpoint of the shaft of various Judd figures in a pretest–practice–posttest design. During practice, half of the participants received feedback about the actual midpoint after each trial, while the other half did not receive feedback. The results showed differences among perceivers of different cultures in judging the midpoints of the shafts of Judd figures, particularly with respect to their propensity to improve perceptual accuracy after repeated practice and feedback. For most participants, changes in illusory bias as a consequence of learning were shown to reflect either a change in what informational variable they exploited or a rescaling or calibration of the perception to the informational variable. However, the individual differences in illusory bias related to culture could not be unequivocally attributed to either of these perceptual-learning processes.     

Walking on an Oscillating Treadmill: Strategies of Stride-Time Adaptation

Gains in mobility, balance, and gait quality have been observed in clinical populations after treadmill training. In our laboratory, we introduce healthy adults to treadmill training programs in an effort to boost their adaptive generalization skills. We hypothesized that some individuals are more naturally predisposed to gait adaptation than others. Stride-time data from 20 healthy adults were collected while they walked on a laterally oscillating treadmill for the first time. We predicted that the more plastic adapters would rapidly synchronize their stride frequencies to the treadmill's oscillation frequency. A treadmill mounted on a 6-degrees-of-freedom motion base platform was programmed to move laterally in a continuous, sinusoidal pattern for 20 min while participants walked at 1.1 m/s. Twenty-five percent of our participants showed a prolonged uninstructed entrained response. Those who did not entrain were still able to adapt to the novel locomotor challenge by applying various alternative strategies. Although entrainment was not required for adaptation, we report compelling evidence that the frequency of the support-surface motion influenced the adapted strategies of 80% of our participants.