The bias function of the maximum likelihood estimate of ability for the dichotomous response level

Samejima has recently given an approximation for the bias function for the maximum likelihood estimate of the latent trait in the general case where item responses are discrete, generalizing Lord's bias function in the three-parameter logistic model for the dichotomous response level. In the present paper, observations are made about the behavior of this bias function for the dichotomous response level in general, and also with respect to several widely used mathematical models. Some empirical examples are given.     

Teacher rated problems and school ability tests in relation to preschool problems and parents'' health information at school start. A study of first-graders

The reliability of assessments at four and six years of age in identifying teacher rated problems in behaviour, concentration, motor skill and school achievement was investigated in a study of first-graders. Relationships between preschool data and school ability tests, and between parents' information at school start and teacher ratings were also studied. Problems noted in preschool and school were often present in more than one area. Multiple problems at four and six years were strong predictors of later school problems, but preschool assessments of separate areas could not in general predict problems in corresponding areas in school. However, cross situational concentration deficits at the age of six did reliably identify concentration problems in the first grade, at the age of seven.     

Another look at “tummy time” for primary plagiocephaly prevention and motor development

It is three decades since it was recommended that infants sleep on the back to reduce risk of sudden unexpected infant death (SUID). The SUID prevention program is known as “back to sleep” or “safe sleeping”, and this initiative is not questioned. Sleeping on the back is associated with, but not the cause of, the development of infant positional plagiocephaly, also known as deformational or a non-synostotic misshapen head when the skull sutures are open, not fused. This paper provides a synthesis of the history and impact of positional plagiocephaly. It includes a scoping review of plagiocephaly prevention facilitating motor development and reveals few articles on primary prevention which aims to prevent it developing in the first place. It is concerning that preschool-aged children with a history of infant plagiocephaly continued to receive lower developmental scores, particularly in motor development, than unaffected controls, and this may be a marker of developmental delay. Tummy-time (prone) for play is the mainstay of plagiocephaly prevention advice to minimize development of plagiocephaly and to facilitate infant motor development, particularly head control. While tummy-time has shown benefit for infant development, there is limited evidence of its effectiveness in preventing plagiocephaly and some evidence that it promotes only prone-specific motor skills. Most of the published literature is concerned with treatment post-diagnosis, in the form of reviews, or clinical notes. There is a plethora of opinion articles reinforcing tummy-time from birth for plagiocephaly prevention. The review shows that there are gaps in advice for early infant development of head control. An accepted test of head control in infants is “pull to sit” from supine which demonstrates antigravity strength of the neck flexors and coordination of the head and neck when the infant is drawn to sit from supine. This motor skill was cited as achievable by 4 months in the earliest paper on plagiocephaly in 1996. Physical therapists and others should revisit the mechanism of early infant head control development against gravity, particularly antigravity head, neck and trunk coordinated flexion movement in supine, as there has been little attention to early facilitation of this motor skill as a plagiocephaly prevention strategy. This may be achieved by considering “face time” as well as tummy time for primary prevention of plagiocephaly.     

Unweighting infants reveals hidden motor skills

We investigated the role of rate limiting factors in development using walking as a model system. The achievement of bipedal posture and locomotion are among the most significant achievements in an infant's first year, with poor balance and weak muscles long proposed as the rate limiting factors. Compensating for either may reveal upright motor skill that has not yet emerged in the infant's natural repertoire. To probe this question, we unweighted prewalking infants and measured their performance in various standing and walking behaviors while unweighted compared to baseline. Our secondary objective was to determine if the influence of unweighting was related to infants’ locomotor experience. Infants stood unsupported for longer durations with 20% or 40% unweighting. Infants took more independent steps and more steps with one hand held with 40% unweighting. No differences in transition to/from standing were observed. Locomotor experience was related to the influence of unweighting during cruising and walking with a push toy. This is the first report of more advanced motor skills—longer periods of unsupported standing and the emergence of independent walking—revealed by unweighting infants. We interpret our observations to suggest that the refinement of motor control needed to support bipedal posture and locomotion precedes the functional emergence of these skills in infants. In other words, the musculoskeletal components required for walking are slower to develop than the neurological factors – and consequently may be the rate limiters. We further suggest that training regimens including unweighting should be explored in infants with motor delays.     

The mediational role of motivation in the model of motor development in childhood: A longitudinal study

The aim of this study was twofold: first, to examine the stability of the hypothesized conceptual model of motor development (without and with including various types of motivation) when children are followed up one-year later, and second to examine longitudinally whether changes in one model variable predict changes in other variables, according to the hypothesized pathways in the model. A sample of 361 Spanish students (50.7% girls, 8–11 years old) voluntarily participated in this study. In relation to the first aim, structural equation modeling revealed the expected positive relationship between the model variables in both measurement times. That is: actual motor competence (MC) predicted physical activity (PA) (p < .001), perceived MC mediated the relationship between actual MC and PA (p < .001), and autonomous motivation mediated the relationship between perceived MC and PA (p < .05). Moreover, the comparison of the invariance analysis showed non-practical differences between the unconstrained model and the constrained model, supporting the stability of the model over time. In relation to the second aim, the hypothesized model in Time 2 controlling for Time 1 values showed that changes in children’s actual MC positively predicted changes in their perceived MC (p < .001), which in turn, predicted changes in their autonomous motivation (p < .001), and PA (p < .001) at Time 2. Based on these findings Physical Education teachers are recommended to foster children’s actual and perceived MC as well as their autonomous motivation over time in order to promote PA strategies for lifelong health.     

Behavioral profile of amisulpride in agonistic encounters between male mice

Amisulpride is a substituted benzamide derivative that acts as a selective dopamine D2/D3 receptor antagonist. Although the anti‐aggressive properties of neuroleptic drugs are well known, the effects of amisulpride on agonistic interactions have not been explored, and there are no studies comparing acute and subchronic effects of this compound on aggression in rodents. In this study, we examined the action of amisulpride (5–25 mg/kg, i.p), administered acutely or subchronically for 10 days, on agonistic behavior elicited by isolation in male mice. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. After acute treatment, amisulpride (5–20 mg/kg) exhibited an ethopharmacological profile characterized by a marked decrease of offensive behaviors (threat and attack) without an impairment of motor activity. By contrast, the anti‐aggressive action of the highest dose used (25 mg/kg) was accompanied by a weak increase of immobility. Body care was also significantly enhanced after treatment with the drug (20 and 25 mg/kg), emphasizing the involvement of dopaminergic receptors in this behavior. After subchronic treatment, no tolerance to amisulpride anti‐aggressive activity was observed. Overall, this behavioral profile is similar to that observed by other atypical neuroleptics. Aggr. Behav. 25:225–232, 1999. © 1999 Wiley‐Liss, Inc.     

Novel odors evoke risk assessment and suppress appetitive behaviors in mice

The effects of four novel odors on risk assessment by mice (i. e., flat back approach, stretched attention, immobility) and the suppression of appetitive behaviors were examined in two experiments. When novel odors were presented in a straight runway, subjects spent significantly less time in the odor compartment, relative to controls, when it contained sheep wool, chocolate, or citronella (but not cat fur) odors. Risk assessment behaviors occurred at similar levels among all groups and appetitive behaviors were not suppressed by the novel odors. When odorants were scattered over one half of the subjects' home cage floor in Experiment 2, all novel odors increased the duration of at least on e risk assessment measure and/or suppressed appetitive behaviors (i. e., eating, grooming, rearing). The results clearly reveal that a reasonably wide range of novel odors evoke at least some level of risk assessment which presumably reflects increased fearfulness. The odors of sheep wool and cat fur induced a wider range of such responses than did chocolate or cinnamon suggesting that mammalian odors may be particularly effective stimuli. If so, however, it is clear that predator odors are not uniquely effective in this regard. Experiment 1 also underscores the importance of the testing environment in assessing the behavioral effects of novel odors in mice. © 1993 Wiley-Liss, Inc.     

Logistic positive exponent family of models: Virtue of asymmetric item characteristic curves

The paper addresses and discusses whether the tradition of accepting point-symmetric item characteristic curves is justified by uncovering the inconsistent relationship between the difficulties of items and the order of maximum likelihood estimates of ability. This inconsistency is intrinsic in models that provide point-symmetric item characteristic curves, and in this paper focus is put on the normal ogive model for observation. It is also questioned if in the logistic model the sufficient statistic has forfeited the rationale that is appropriate to the psychological reality. It is observed that the logistic model can be interpreted as the case in which the inconsistency in ordering the maximum likelihood estimates is degenerated.The paper proposes a family of models, called the logistic positive exponent family, which provides asymmetric item chacteristic curves. A model in this family has a consistent principle in ordering the maximum likelihood estimates of ability. The family is divided into two subsets each of which has its own principle, and includes the logistic model as a transition from one principle to the other. Rationale and some illustrative examples are given.     

A hierarchical latent response model for inferences about examinee engagement in terms of guessing and item-level non-response

In low-stakes assessments, test performance has few or no consequences for examinees themselves, so that examinees may not be fully engaged when answering the items. Instead of engaging in solution behaviour, disengaged examinees might randomly guess or generate no response at all. When ignored, examinee disengagement poses a severe threat to the validity of results obtained from low-stakes assessments. Statistical modelling approaches in educational measurement have been proposed that account for non-response or for guessing, but do not consider both types of disengaged behaviour simultaneously. We bring together research on modelling examinee engagement and research on missing values and present a hierarchical latent response model for identifying and modelling the processes associated with examinee disengagement jointly with the processes associated with engaged responses. To that end, we employ a mixture model that identifies disengagement at the item-by-examinee level by assuming different data-generating processes underlying item responses and omissions, respectively, as well as response times associated with engaged and disengaged behaviour. By modelling examinee engagement with a latent response framework, the model allows assessing how examinee engagement relates to ability and speed as well as to identify items that are likely to evoke disengaged test-taking behaviour. An illustration of the model by means of an application to real data is presented.     

Motor sequence learning in children with recovered and persistent developmental stuttering: preliminary findings

PurposePrevious studies have associated developmental stuttering with difficulty learning new motor skills. We investigated non-speech motor sequence learning in children with persistent developmental stuttering (CWS), children who have recovered from developmental stuttering (CRS) and typically developing controls (CON).MethodsOver the course of two days, participants completed the Multi-Finger Sequencing Task, consisting of repeated trials of a10-element sequence, interspersed with trials of random sequences of the same length. We evaluated motor sequence learning using accuracy and response synchrony, a timing measure for evaluation of sequencing timing. We examined error types as well as recognition and recall of the repeated sequences.ResultsCWS demonstrated lower performance accuracy than CON and CRS on the first day of the finger tapping experiment but improved to the performance level of CON and CRS on the second day. Response synchrony showed no overall difference among CWS, CRS and CON.Learning scores of repeated sequences did not differ from learning scores of random sequences in CWS, CRS and CON. CON and CRS demonstrated an adaptive strategy to response errors, whereas CWS maintained a high percentage of corrected errors for both days.ConclusionsOur study examined non-speech sequence learning across CWS, CRS and CON. Our preliminary findings support the idea that developmental stuttering is not associated with sequence learning per se but rather with general fine motor performance difficulties.