PIGEONS ARE SENSITIVE TO THE SPATIAL ORGANIZATION OF COMPLEX VISUAL STIMULI

Abstract— Two experiments investigated the role of spatial organisation in the discrimination and generalization of complex visual stimuli by pigeons. In Experiment 1, after pigeons had been trained to discriminate line drawings of four objects, they were tested with novel pictures in which the same component parts of the objects were spatially rearranged. The spatially scrambled pictures led to a dramatic drop in recognition accuracy, hut responding remained above chance. In Experiment 2, pigeons reached a high level of discriminative performance when required to choose among four different spatial arrangements of the same object parts. These results confirm Cerella's (1980) conclusion that pigeons discriminate the component parts of complex visual stimuli, but. unless it is assumed that the scrambling deleted or created emergent features, the results disconfirm his conclusion that spatial organization plays no role in pigeons' picture perception.     

Interrelationships among students' study activities,self-concept of academic ability,and achievement as a function of characteristics of high-school biology courses

This investigation focused on the interrelationships among students' study activities, students' self-concept of academic ability ratings, students' academic achievement, and instructional practices in 12 high school biology courses. Using a framework derived from a previous investigation, course features were classified into those that appear to (a) place demands on, (b) support, or (c) compensate for student engagement in particular study activities. Students' study activities, self-concept of academic ability ratings, and achievement were measured with experimenter-developed instruments. Results are reported for (a) characteristics of instruments and course features, (b) relationships between central factors of the investigation, and (c) multi-level relationships between course features and student variables. Results at the student level indicated that self-concept of academic ability and, to a lesser extent, students' study activities were positively associated with student achievement. Students' self-concept of academic ability ratings were also linked to students' engagement in generative, proactive study activities. At the course level the supportive practices of providing challenging homework assignments and extensive feedback on student coursework were associated with student engagement in effortful, generative, proactive study activities. The provision of extensive feedback was also associated with high student achievement. Multi-level relationships were analysed using hierarchical linear modelling (HLM) analyses. These analyses revealed, for example, that in courses in which little or no feedback is given on homework assignments, the relationship between achievement and student engagement in diligent effort management activities was enhanced. Other HLM analyses were conducted to examine the mediating role of course features on the relationship between students' self-concept of academic ability and their study activities and achievement. For example, the presence of challenging course demands was associated with an enhancement of the relationship between self-concept of academic ability and achievement whereas the presence of instructor provisions (supports and compensations) designed to reduce course demands was associated with a reduction in this relationship.     

Offering predictive testing for Huntington disease in a medical genetics clinic: Practical applications

Predictive testing for Huntington disease is presently offered in a select few medical genetics centers in the United States. This is in part due to the labor intensive counseling and psychological testing suggested by the research protocols. We discuss some specific suggestions for establishing programs for Huntington disease predictive testing within pre-existing medical genetics clinics to encourage more centers to offer presymptomatic testing. This will allow more at risk individuals the opportunity to consider predictive testing and cut down the expenses of traveling to the few predictive testing centers that currently exist. The counseling principals will remain similar to those discussed here, even following the identification of the Huntington disease mutation.     

Family preservation using multisystemic treatment: Long-term follow-up to a clinical trial with serious juvenile offenders

In a randomized clinical trial, multisystemic family preservation was shown to significantly reduce rates of criminal activity and incarceration in a sample of 84 serious juvenile offenders and their multi-need families. In the current study, archival records were searched for re-arrest an average of 2.4 years post-referral. Survival analysis showed that youths who received multisystemic family preservation were less likely to be re-arrested than were youths who had received usual services. Such results represent the first controlled demonstration that family preservation, when delivered via a clearly specified treatment model, has lasting effects with serious juvenile offenders. Implications for family preservation and juvenile justice research are discussed.     

Quality care in residential placement for children and youth with developmental disabilities

There is a growing concern for quality care in residential placements outside of the natural family for children and youth with developmental disabilities. Ideally, children with developmental disabilities should remain with their natural parent or parents of parents with appropriate supports until the age when children typically leave home. In reality, parents of children and youth with development disabilities are not always able or willing to care for their children at home, and alternate residential placements must be found. This paper will discuss some of the issues surrounding the provision of quality care in out-of-home residential placements for children and youth with developmental disabilities.     

Images of black women among anglo college students

Previous research on popular images of women and of minority groups has looked almost solely at images of minority men and of white women. This article presents survey data on images of black women among 256 white non-Hispanic college undergraduates, using a modified Katz/Braly scale. The article explores the nature, distribution, correlates, and emotional evaluations of these images and the implications of these images for black women's lives. Images of black women differed substantially from those of American women in general. Most commonly, black women were characterized as loud, talkative, aggressive, intelligent, straightforward, and argumentative. In addition, students rated positive traits less positive and negative traits less negative when exhibited by black women than by American women in general, apparently because of their expectations for black women's behavior.This paper has benefited from the comments of Verna Keith, Wade Smith, and, most especially, Mary Benin. This research was partially supported by Arizona State University Women's Studies Summer Research Awards Program.     

Social Interactions of Obese and Nonobese Women

The stigma associated with obesity is likely to limit the opportunities obese women have to develop social skills. This hypothesis was tested by having obese (n = 15) and nonobese (n = 22) women converse on the telephone with college students who were unaware of the women's weights. Ratings made by judges who listened to the women's contributions to the conversations but who were unaware of their weights showed that obesity was negatively related to judgments about the women's likability, social skills, and physical attractiveness. The telephone partners of obese women rated the women and themselves more negatively than did the partners of nonobese women. Obese and nonobese women generally did not differ in their evaluations of their own and their telephone partners' behavior, and they also did not differ on a measure of social self-esteem. These findings suggest that there are real differences in the social behavior of obese and nonobese women and that these differences affect the impressions formed by those with whom they interact.     

Cholinergic-dopaminergic interactions in cognitive performance

Both acetylcholinergic (ACh) and dopaminergic (DA) systems have been found to be crucial for the maintenance of accurate cognitive performance. In a series of studies examining those aspects of cognitive function revealed by the radial-arm maze, we have found that these two neurotransmitter systems interact in a complex fashion. Choice accuracy deficits in the radial-arm maze can be induced by blockade of either muscarinic- or nicotinic-ACh receptors. The choice accuracy deficit induced by blockade of muscarinic receptors with scopolamine can be reversed by the DA receptor blocker, haloperidol. The specific DA D1 blocker SCH 23390 also has this effect, whereas the specific D2 blocker raclopride does not, implying that it is D1 blockade that is critical for reversing the scopolamine effect. On the other hand, the choice accuracy deficit induced by nicotinic blockade with mecamylamine is potentiated by haloperidol. This effect is also seen with the D2 antagonist raclopride, but not with the D1 antagonist SCH 23390, implying that it is the D2 receptor which is important for the potentiation of the mecamylamine effect. The relevance of the D2 receptor for nicotinic actions on cognitive function is emphasized by the finding that the selective D2 agonist LY 171555 reverses the choice accuracy deficit caused by mecamylamine. Nicotinic and muscarinic blockade are synergistic in the deficit they produce. Antagonist doses subthreshold when given alone produce a pronounced impairment when given together. This latter deficit can be reversed by the D2 agonist LY 171555. These studies have outlined the complex nature of ACh-DA interactions with regard to cognitive function. Possible neural circuits for these interactions are discussed. The effectiveness of these selective DA treatments in reversing cognitive deficits due to ACh underactivation suggests a novel approach to treating cognitive dysfunction in syndromes such as Alzheimer's disease.     

The effects of polydrug use with and without cocaine on mother-infant interaction at 3 and 6 months

The face-to-face interactions of 43 polydrug-with-cocaine-using mothers and their infants at 3 and 6 months were compared to 17 non-cocaine-but other-drug-using mothers and 21 mothers who used no drugs during their pregnancy. Coders blind to mothers' drug use status scored 3 min of face-to-face interactions for 16 measures of maternal and infant interactive behaviors. A principal component of 7 behaviors formed a measure of maternal attentiveness; a principal component of 5 behaviors formed a measure of mother-infant dyadic organization; and a principal component of 4 behaviors formed a measure of infant readiness to interact. A measure of maternal interruption was computed as the mean standard score of 3 additional interruptive behaviors. At 3 and 6 months, polydrug-with-cocaine-using mothers were less attentive to interactions, and polydrug-with-cocaine-using mothers and their infants engaged in fewer dyadic interactions than either non-cocaine or non-drug-using mothers. Compared to 3 months, polydrug-with-cocaine-using mothers at 6 months were less attentive to interactions and more frequently interrupted interactions by looking away, redirecting the infant, or withdrawing, whereas non-cocaine-using and non-drug- using mothers showed no change or an improvement in attentiveness to interactions and a decrease in interruptions. No differences emerged in the interactive behaviors of the infants of polydrug- with-cocaine-using, non-cocaine-using, or non-drug-using mothers. Cocaine use represents a significant risk for diminished parental attentiveness and responsiveness to infants and for diminished interactiveness in infants.