Mediating factors in chick social pecking: II. effects of exposure to movement

Unfamiliarity with movement may lead isolated chicks to respond aggressively when tested with live, moving conspecifics. This hypothesis was tested by comparing the number and locus of pecks by isolated chicks to a stationary or moving model of a chick, and to a live chick. In a second test of the hypothesis chicks that viewed a moving object during isolation and chicks isolated without movement were tested with a live con-specific and their number and locus of pecks were compared. Neither experiment supported the hypothesis. Movement alone failed to excite aggressive pecks and prior experience with movement failed to suppress aggressive pecks. In the first experiment imlated chicks treated the live testmate more aggressively than the moving or stationary model. In the second experiment aggressive pecking of chicks was unaffected by prior experience with movement, These fmdmgs do not support the hypothesis that movement excites aggression in isolated chicks. Nonetheless the results focus attention on the generally neglected problem of emotional and motivational states produced by isolation.     

An overview of applied robust methods

Data in social sciences are typically non-normally distributed and characterized by heavy tails. However, most widely used methods in social sciences are still based on the analyses of sample means and sample covariances. While these conventional methods continue to be used to address new substantive issues, conclusions reached can be inaccurate or misleading. Although there is no ‘best method’ in practice, robust methods that consider the distribution of the data can perform substantially better than the conventional methods. This article gives an overview of robust procedures, emphasizing a few that have been repeatedly shown to work well for models that are widely used in social and behavioural sciences. Real data examples show how to use the robust methods for latent variable models and for moderated mediation analysis when a regression model contains categorical covariates and product terms. Results and logical analyses indicate that robust methods yield more efficient parameter estimates, more reliable model evaluation, more reliable model/data diagnostics, and more trustworthy conclusions when conducting replication studies. R and SAS programs are provided for routine applications of the recommended robust method.     

Growing Together—Effects of a school-based intervention promoting positive self-beliefs and social integration in recently immigrated children

We present a school-based intervention geared to foster the social integration of recently immigrated (RI) primary school children by creating repeated positive contact situations with classmates brought up in the receiving society. Coaches encouraged groups of tandems, consisting of one RI and one child brought up in Germany each, to engage in cooperative activities designed to strengthen positive self-beliefs and perception of equal status. In a quasi-experimental control-group design (N = 318), we compared the 30 children (12 RI) who participated in our intervention between pre-test and post-test with a reference group. Self-beliefs were measured via self-reports, social integration via sociometric peer-nominations. The reference group (n = 288 children) included all children who did not participate in the intervention between pre-test and post-test: (a) 12 children (7 RI) of a waiting control group and (b) all classmates of both the students of the intervention and the waiting control group. Post-test self-beliefs were more positive in children having participated in the intervention. The intervention did not affect social integration: Neither the number of classmates nominating a student nor the number of peers the respective student nominated increased. Possibly, the intervention initiated self-reinforcing processes which support social integration over longer time periods.     

Heart-rate deceleration and smiling in 3-month-old infants

The relation between heart-rate deceleration and the expression of positive affect in infancy is examined by testing the hypothesis that intensity of orienting (as indexed by heart-rate deceleration) is predictive of intensity of positive affect (smile size and duration). A social-stimulation procedure was utilized to elicit smiles in 41 3-month-old infants. The first smile elicited was coded for smile size and duration, and the preceding heart-rate deceleration was coded for magnitude, duration, and slope of deceleration. Slope and duration of heart-rate deceleration proved to be reliable predictors of smile size, but none of the heart-rate measures correlated with smile duration. Results suggest that the steeper and more rapid the deceleration, the larger the ensuing smile. Possible mechanisms for this finding are discussed.     

On scaling models applied to data from several groups

Statistical methods are presented to facilitate a more complete analysis of results obtained when a scaling model is applied to data from two or more groups. These methods can be used to (a) compare the corresponding estimated latent distributions obtained using the scaling model applied to the different groups, (b) compare the corresponding estimated item reliabilities (or item response error rates) for the different groups, and (c) test whether the scaling model applied to the several groups can be replaced by a more parsimonious scaling model that includes various homogeneity constraints (i.e., constraints that describe which parameters in the model are the same for the several groups). Various kinds of scaling models are considered here in the multiple-group context.Support for this research was provided in part by the National Science Foundation, to Clogg by Grant No. SES-7823759 and to Goodman by Grant No. SES-8303838. Clogg and Goodman were Fellows at the Center for Advanced Study in the Behavioral Sciences when part of the research was done, with financial support provided in part by National Science Foundation grant BNS-8011494 to the Center. The authors are indebted to Mark P. Becker and James W. Shockey for helpful comments.     

Conjunctive item response theory kernels

Conjunctive item response models are introduced such that (a) sufficient statistics for latent traits are not necessarily additive in item scores; (b) items are not necessarily locally independent; and (c) existing compensatory (additive) item response models including the binomial, Rasch, logistic, and general locally independent model are special cases. Simple estimates and hypothesis tests for conjunctive models are introduced and evaluated as well. Conjunctive models are also identified with cognitive models that assume the existence of several individually necessary component processes for a global ability. It is concluded that conjunctive models and methods may show promise for constructing improved tests and uncovering conjunctive cognitive structure. It is also concluded that conjunctive item response theory may help to clarify the relationships between local dependence, multidimensionality, and item response function form.I appreciate the many helpful suggestions that were given by the reviewers and Ivo Molenaar.     

Speech acts and arguments

Speech act theory seems to provide a promising avenue for the analysis of the functional organization of argument. The theory, however, might be taken to suggest that arguments are a homogenous class of speech act with a specifiable illocutionary force and a single set of felicity conditions. This suggestion confuses the analysis of the meaning of speech act verbs with the analysis of the pragmatic structure of actual language use. Suggesting that arguments are conveyed through a homogeneous class of linguistic action overlooks the way in which the context of activity and the form of expression organize the argumentative functions performed in using language. An alternative speech act analysis would treat folk terminology as a heuristic entry point into the development of a technical analysis of the myriad argumentative functions and structures to be found in natural language use. This would lead to a thorough-going pragmatic analysis of the rational and functional design of speech acts in argumentation.     

PROMOTING RECIPROCAL INTERACTIONS VIA PEER INCIDENTAL TEACHING

This study evaluated peer incidental teaching as a strategy for increasing reciprocal peer interactions by children with autism. Three typical preschoolers were trained as peer tutors for 3 young children with autism. During a classroom free-play session, peer tutors used incidental teaching to obtain verbal labels of preferred toys by children with autism. A multiple baseline across the 3 target children showed replicated positive effects of the intervention. Adult supervision and assistance were then faded systematically, with resulting maintenance of increased reciprocal interactions. Multiple measures of the extent and limits of generalization suggested that 1 child increased interactions in free-play periods throughout the day, but none of the children showed increases at lunch. Teacher and peer ratings supported the social validity of positive findings.