THE EFFECTIVENESS OF A CONSTANT TIME-DELAY PROCEDURE TO TEACH CHAINED RESPONSES TO ADOLESCENTS WITH MENTAL RETARDATION

The effectiveness of a 5-s constant time-delay procedure to teach three chained food preparation behaviors to four moderately retarded adolescent students was evaluated within a multiple probe design across behaviors. Results indicate that the procedure was effective in teaching all four students to make a sandwich, boil a boil-in-bag item, and bake canned biscuits. The skills maintained with at least 85% accuracy over a 3-month period. Training generalized from the school to the home setting for the 2 subjects that completed generalization probe sessions. The percentage of errors across all skills and students was less than 9%.     

Test theory without an answer key

A general model is presented for homogeneous, dichotomous items when the answer key is not known a priori. The model is structurally related to the two-class latent structure model with the roles of respondents and items interchanged. For very small sets of respondents, iterative maximum likelihood estimates of the parameters can be obtained by existing methods. For other situations, new estimation methods are developed and assessed with Monte Carlo data. The answer key can be accurately reconstructed with relatively small sets of respondents. The model is useful when a researcher wants to study objectively the knowledge possessed by members of a culturally coherent group that the researcher is not a member of.This research was supported by NSF Grant No. SES-8320173 to the authors. We gratefully acknowledge comments and suggestions from John Boyd, Tarow Indow, and Kathy Maher as well as the editor and several anonymous referees.     

Visually guided catching and tracking skills in pigeons: A preliminary analysis

Research on reaching, tracking, and catching in the pigeon has been hampered by limitations of technology. A new system was developed in which the target was a small rectangle presented on a video display terminal and the pecking response was detected with touch technology. The target moved up and down vertically with sinusoidal velocity. A coincidence between the location of the pigeon's beak and the cursor produced reinforcement. The pigeon pecked ahead and behind the target, but most pecks occurred behind the target so the dominant tracking strategy was lagging. The pigeon was adept at “catching” the target at many locations throughout the trajectory. Transfer of motor learning was tested on probe trials during which the trajectory changed from vertical to horizontal. On transfer trials the pigeons' dominant pattern of pecking immediately shifted from vertical to horizontal. The motor skill displayed by the pigeons was flexible and adaptive, suggesting that the pigeons had learned to track the cursor.     

Latent trait models and dichotomization of graded responses

This paper discusses thecompatibility of the polychotomous Rasch model with dichotomization of the response continuum. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum, ranging for example from total rejection or disagreement to total acceptance or agreement of an item or statement. Because of this arbitrariness, the measurement outcome should be independent of the specific polychotomization applied, for example, presenting a specific multicategory response format should not affect the measurement outcome. When such is the case, the original polychotomous model is called compatible with dichotomization.A distinction is made between polychotomization or dichotomization before the fact, that is, in constructing the response format, and polycho- or dichotomization after the fact, for example in dichotomizing existing graded response data.It is shown that, at least in case of dichotomization after-the-fact, the polychotomous Rasch model is not compatible with dichotomization, unless a rather special condition of the model parameters is met. Insofar as it may be argued that dichotomization before the fact is not essentially different from dichotomization after the fact, the value of the unidimensional polychotomous Rasch model is consequently questionable. The impact of our conclusion on related models is also discussed.     

Parent and actometer measures of motor activity level in the young infant

Motor activity level is one dimension of infant temperament for which parental judgment can be validated against a truly independent criterion. Two studies were conducted, the first involving a 27-min sample of behavior in a structured, attention-getting situation, and the second involving a 24-hr sample of in-home behavior. In both studies, parent perception of the 3- or 4-month-old as measured by the Activity Level (AL) scale of the Rothbart Infant Behavior Questionnaire was compared to the composited readings from four mechanical motion recorders (actometers) worn, one per limb, by the infant. The AL scale did not correlate with the actometer measure, r=.05 and R=.00, and the expected convergence of the 3-month version of the IBQ activity scale with its mechanical counterpart was not found. In the 24-hr study, birth order and ponderal index were significantly correlated with 24-hr actometer scores; first-borns and thin infants were most active.     

大学生镜像书写及其机制探讨

本研究选择60名右利大学生(男女各半)为被试,在笔划水平上对十四种不同书写方式下快速书写时所出现的自发性镜像书写进行了研究。所有被试随机分为人数相等的实验、对照两组,组内男女各半。对实验组加以注意干扰。书写内容是十个阿拉伯数字(0—9)及十三个汉字组成的一句话。本研究结果表明:注意干扰、感觉的反馈调节,书写内容的特点是影响镜像书写出现的重要因素。作者在分析国内外有关镜像书写工作的基础上,进一步提出了“稳态系统”理论。     

A review of behavioral procedures to teach motor skills to individuals with severe disabilities

Behavioral procedures are one approach to teaching or improving the fluency of motor skills of individuals with severe disabilities. This article provides a review of behavioral procedures by highlighting antecedents, consequences, and multifaceted techniques. Investigations are reviewed in each area according to (a) replicability of the intervention, (b) experimental control, (c) maintenance, (d) generalization, and (e) social validation. Practitioner implications address selection of reinforcers, reinforcement schedules, and teaching within meaningful routines. Future research recommendations highlight the need for documenting that stimuli are actually reinforcers. Additional research needs emphasize targeting maintenance, generalization, and social validation.     

Practices and representations of child care and motor development among West Africans in Paris

Massage techniques and postural manipulation used by West African women immigrants in Paris were studied, with the aim of demonstrating that culturally regulated caretaking practices have an influence on infant motor development. Twenty-five infants were observed between the ages of 3 and 12 months and 9 and 15 months. Frequency of massage and its accompanying set of physical exercises were found to be related to age at onset of independent walking. The findings show that infants receiving daily massage walk significantly earlier than infants who do not receive massage, thus confirming other reports that vestibular and postural stimulation have a positive effect on motor development. These results are discussed in relation to the observed frequencey of contact and of physical games with the caregiver for a smaller sample of three infants, and to parental expectations about the age of acquisition of certain cognitive and motor abilities. African immigrant mothers expect their infants to sit and to walk earlier than French mothers. The conclusion emphasizes the contribution of social anthropology, which shows that in all cultures, physical development and body changes elicit symbolic practices and a search for explanation.     

A NOTE ON TRANSFER OF STIMULUS CONTROL IN THE DELAYED-CUE PROCEDURE: FACILITATION BY AN OVERT DIFFERENTIAL RESPONSE

This case study describes initially unsuccessful attempts to use the delayed-cue procedure to teach conditional discriminations to an individual with moderate mental retardation. The task was matching printed-word comparison stimuli to dictated-name sample stimuli. In three experiments, the subject typically waited for the delayed cue unless differential responses to the dictated samples (repeating the sample names) were required. Hence, the study provides an example of a way to make the delayed-cue method more effective. The stimulus control bases for the results are discussed.     

Predicting and scaling hens' preferences for topographically different responses

Six hens were exposed to several concurrent (second-order) variable-interval schedules in which the response requirements on the alternatives were varied. The response requirements were one key peck versus five key pecks, one key peck versus one door push, and five key pecks versus one door push. Response- and time-allocation ratios undermatched the obtained reinforcement ratios but were well described by the generalized matching law. Time and response bias estimates from two pairs of response requirements were used to predict bias in the third pairing. The predicted values were close to those obtained; this result supports the notion that both numerically and topographically different responses act as constant sources of bias within the generalized matching law. The differences between the response and time biases could be accounted for by the different times needed to complete each response requirement. The results also suggest that the door push is a useful operant for research with domestic hens.