Transfer across CS-US intervals and sensory modalities in classical conditioning of the rabbit

Two experiments investigated transfer of the rabbit’s conditioned nictitating membrane response (NMR) from shorter to longer CS-US intervals in conjunction with a change in CS modality, for example, light to tone. In Experiment 1, three experimental groups received initial training with a 400-msec CS-US interval, which produced substantial CR acquisition, and three control groups received initial training with a 2,800-msec CS-US interval, which produced minimal CR acquisition. Subsequently, the experimental and control groups received training with an 800-, 1,800-, or 2,800-msec CS-US trace interval. At the same time, the modality of the CS was changed from tone to light (or vice versa). Experiment 2 contained three groups that received initial exposure to a 400-msec CS-US interval, a 2,800-msec CS-US interval, or just the experimental chambers. Subsequently, all three groups received training with an 800-msec CS-US interval in a different CS modality. The results of both experiments revealed substantial positive transfer across CS modalities from the 400-msec CS-US interval to the 800-msec CS-US interval. There was also significant transfer to the 1,800-msec but not the 2,800-msec CS-US interval. The transfer did not appear immediately on test presentations of the second CS. Rather, the transfer appeared as an enhancement in the rate of CR acquisition after reinforced training with the second CS had commenced. The results are discussed with respect to mechanisms of transfer and facilitation of trace conditioning.     

Behavioral problems among children whose mothers are abused by an intimate partner

OBJECTIVES: To determine the association between children's exposure to maternal intimate partner violence (IPV) and behavior problems as measured by the parent report version of the Child Behavior Checklist (CBCL). METHODS: The study population was comprised of 167 2- to 17-year-old children of Seattle women with police-reported or court-reported intimate partner abuse. The CBCL normative population served as the comparison group. Risk of behavior problems was calculated among the exposed children, in the presence and absence of a history of reported child maltreatment, relative to the normative population. Multiple logistic regression served as the primary method of analysis. RESULTS: Children exposed to maternal IPV were more likely to have borderline to clinical level scores on externalizing (i.e., aggressive, delinquent) behavior (RR=1.6, 95% CI: 1.2, 2.1) and total behavioral problems (RR=1.4, 95% CI: 1.1, 1.9) compared to the CBCL normative sample after adjusting for age and sex. Children who were exposed to maternal IPV and were victims of child maltreatment were more likely to receive borderline to clinical level scores on internalizing (i.e., anxious, depressed) behaviors (RR=2.6, 95% CI: 1.5, 3.6), externalizing (i.e., aggressive, delinquent) behaviors (RR=3.0, 95% CI: 1.9, 4.0) and total behavioral problems (RR=2.1, 95% CI: 1.2, 3.2) compared to the CBCL normative sample after adjusting for age and sex. CONCLUSIONS: Exposure to maternal IPV is significantly associated with child behavioral problems both in the presence and absence of co-occurring child maltreatment. Appropriate attention to the mental health of children living in households with IPV is needed.     

Emotional and Behavioral Predictors of Preschool Peer Ratings

It was predicted that social cognitive, behavioral, and affective aspects of young children's social development would predict stable peer ratings of their likability. Measures of likability, emotion knowledge, prosocial and aggressive behavior, peer competence, and expressed emotions (happy and angry) were obtained for 65 subjects (mean age = 44 months). Sociometric ratings, particularly negative, were stable over 1- and 9-month time periods. Correlational analyses showed that emotion knowledge and prosocial behavior were direct predictors of likability. Prosocial behavior mediated the relations of gender and expressed emotions with likability (i.e., gender and expressed emotions were each related to prosocial behavior, and prosocial behavior was related to likability, but neither gender nor expressed emotions were related to likability with prosocial behavior partialled out). Knowledge of emotional situations similarly mediated the age-likability relation. Results uphold the early development of stable peer reputations and the hypothesized centrality of emotion-related predictors of likability.     

Making connections: the logical structuring of hypertext documents

The results from an experiment analysing hypertextual semantic linking is reported. In the study participants are asked to describe logical relationships between related, semi-related and unrelated paragraphs of text. It is concluded that existence and themes of relationships are (as expected) fairly consistently recognised, however, specific relationships do not readily fall into natural predicate like statements. Purely thematic relationships, or a palette of available relationships might be the more practical approach. Further work on dynamic linking in hypertext documents is also reported. Dynamic linking eliminates some of the problems associated with a mismatch between the mental models of authors and readers and allows the readers to construct their own hypertexts from linear documents. This approach offers useful data on logical connectivity in hypertext documents but also represents an alternative to conventional hypertext authoring and reading.     

A developmental perspective on dyslexic subtypes

In this paper we apply a developmental model of reading to the question of dyslexic subtypes. Groups of normal readers (n=40) and dyslexic children (n=50), matched on reading level and IQ, were given a comprehensive test battery measuring level of development of visual, phonological, and orthographic skills. As a group, dyslexics deviated from normal readers of equivalent reading achievement primarily in phonological skills (spelling-to-sound translation and phonemic analysis), although limited differences in knowledge of word-specific spellings were also observed. Dyslexics were superior to the younger normal readers in visual processing of print. Analysis of individual data by reference to the reading level control group revealed three major subgroups: a group with a specific deficit in phonological processing of print (52 percent), a group with deficits in processing both the phonological and orthographic features of printed words (24 percent), and a group with phonological deficits in language (8 percent). The remainder of the sample (16 percent) had specific deficits in visual or orthographic processing of print, in spelling, or did not differ from the control group. The data support the view that most developmental dyslexics have a specific language disorder involving some aspect of phonological processing. However, small subgroups with very different configurations of reading and nonreading difficulties may exist as well. This research was supported by an NICHD grant to the first author (USPHS grant 1 R23 HD20231).     

General transfer across sensory modalities survives reductions in the original conditioned reflex in the rabbit

Two experiments demonstrated that transfer of training between CSs from different sensory modalities survived substantial reductions in responding to the first CS. In both experiments, animals received three stages of training. Stage 1 entailed CS-US training with a CS from one modality (e.g., light), and Stage 3 entailed CS-US training with a CS from another modality (e.g., tone). The experiments differed in treatment during Stage 2. In Experiment 1, animals either remained in their home cages or received unreinforced exposures to the first CS, which extinguished the original CR. In Experiment 2, the animals received either continued CS-US training or exposure to the CS and US but at a long interval (2,800 msec), which eliminated the original CR. As the baseline for detection of transfer effects, each experimental group had a control group that received Stage 1 training with a 2,800-msec CS-US interval, which produced minimal CR acquisition. The results of both experiments revealed substantial positive transfer across CS modalities regardless of the treatment during Stage 2. The transfer did not appear immediately on test presentations of the second CS in Stage 3. Rather, the transfer appeared as an enhancement in the rate of CR acquisition after reinforced training with the second CS had commenced. The results are discussed with respect to stimulus generalization, neutralization of background stimuli, and learning processes superordinate to specific associations.