Spatial relational memory in 9-month-old macaque monkeys

This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys (Macaca mulatta). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in one of two sets of three distinct locations. Monkeys were tested in two different conditions: (1) when local visual cues marked the two sets of potentially baited locations, so that monkeys could use both local and spatial information to discriminate these locations from never-baited locations; and (2) when no local visual cues marked the two sets of potentially baited locations, so that monkeys had to rely on a spatial relational representation of the environment to discriminate these locations. No 9-mo-old or adult monkey associated the presence of the proximal landmarks, at the center of the arena, with the presence of food in one set of three distinct locations. All monkeys, however, discriminated the potentially baited locations in the presence of local visual cues, thus providing evidence of visual discrimination learning. More importantly, all 9-mo-old monkeys tested discriminated the potentially baited locations in absence of the local visual cues, thus exhibiting evidence of spatial relational learning. These findings indicate that spatial memory processes characterized by a relational representation of the environment are present as early as 9 mo of age in macaque monkeys.     

Cholinergic modulation of trace conditioning trained in serial compound: A developmental analysis

In four experiments the effects of serial compound conditioning on responding to a trace-conditioned CS were evaluated using a fear conditioning paradigm. The subjects were 18- and 25-day-old Sprague-Dawley rats, previously shown to exhibit little or no trace fear conditioning. Here, animals as young as 18 days of age were shown to be capable of trace conditioning between a visual CS1 and a shock US, provided the trace interval was filled with a non-target CS2 during serial conditioning trials (CS1-->CS2-->US). To explore cholinergic mechanisms involved in trace and serial conditioning, additional experiments assessed conditioned responding following pre-training administration of the muscarinic receptor antagonist scopolamine. Scopolamine produced a dose-dependent reduction in responding to the trace CS1, regardless of whether subjects were trained with standard trace (CS1-->trace interval-->US) or serial (CS1-->CS2-->US) trials. Responding to CS2 was unaffected by scopolamine. These data suggest that central cholinergic systems are functional in the young animals, but are not normally sufficiently activated by standard trace conditioning procedures. The results suggest that serial compound conditioning can promote trace conditioning in young rats, as it does in adults, perhaps by enhancing cholinergic activity during training. Implications for the late ontogenetic emergence of trace conditioning as it relates to maturation of neural pathways and their role in the potentiating effects of a gap filler are discussed.     

Word list generation performance in Alzheimer's disease and vascular dementia

Word list generation (WLG) was examined among clinical samples of individuals with Alzheimer's disease (AD) (n = 73) or ischemic vascular dementia (IVD) (n = 85), equivalent in age, education, current and estimated premorbid intellectual functioning, and proportion of men and women. The AD group performed significantly better than did the IVD group on lexical WLG, and a trend was observed indicating superior performance among the IVD group on categorical WLG. Within-groups, comparisons of group means, and profile analyses of individual performance patterns all indicated that persons with AD demonstrated a lexical > categorical pattern significantly more often than did IVD participants. The absolute difference in average performance between the AD and IVD groups on lexical and categorical WLG was small; the findings, however, generally support the clinical utility of the lexical > categorical WLG pattern in the differential diagnosis of AD and IVD. The patterns of performance support the presence of relative impairment in semantic processing among the individuals with AD and global deficits in retrieval and processing speed in individuals with IVD.     

Experiences of being homeless or at risk of being homeless among Canadian youths

A qualitative study was undertaken with four groups--immigrants, youths, Aboriginal people, and landlords--in order to explore, compare, and contrast diversity issues among the homeless population and those at risk of homelessness in a larger Canadian city (Calgary, Alberta) with a smaller city (Lethbridge, Alberta), to better understand their and to needs make recommendations for improvement in service delivery and policy formation. This paper focuses on the findings from our sample of youths who shared information on a range of factors that contributed to their being homeless or at risk of being homeless. The youths in this study also shared their positive as well as negative experiences with educators, peers, family members, and social service providers. Canada's homeless include growing numbers of young people, families, women, and members of various ethnic communities, including Aboriginal people and immigrants. Today it is no longer possible to articulate a single silhouette of the homeless, but rather a diversity of profiles is needed. It was in the light of this reality that a study, "Diversity Among the Homeless and Those At Risk," was carried out. It was undertaken with four groups--immigrants, youths, Aboriginal people, and landlords.     

Religion as a resource for positive youth development: religion, social capital, and moral outcomes

Although existing literature demonstrates that developmental benefits are associated with religion for adolescents, little is understood about the dynamics of this relationship. Drawing on social capital theory, this study tested a conceptual model exploring socially embedded religious influences on moral outcomes. A three-dimensional model of social capital demonstrated how social interaction, trust, and shared vision enable social ties associated with religiousness to influence moral behavior. Structural equation modeling was used with data gathered from 735 urban youths to test a proposed model of the effects of religiousness on moral outcomes. Results suggested that religiously active youths report higher levels of social capital resources and that the influence of adolescent religiousness on moral outcomes was mediated through social capital resources. Suggestions for further research and implications for faith-based youth development organizations are considered.     

Feeling better about doing worse: social comparisons within romantic relationships

The authors examined the role of closeness between self and partner in determining the impact of social comparisons within intimate relationships. To the extent that one's partner is a central aspect of one's identity, one may be able to restore one's positive self-regard following an upward comparison with the partner by turning to the relationship as a self-affirmational resource. Studies 1 and 2 examined reactions to imagined comparisons; Studies 3 and 4 examined reactions to actual comparison feedback. Across studies, closeness moderated the impact of upward comparisons with the partner; that is, higher closeness participants responded to a more successful partner by focusing on their relationship-related strengths. However, closeness did not moderate the impact of downward comparisons with the partner.     

Teaching safety skills to children to prevent gun play: an evaluation of in situ training

This study evaluated behavioral skills training with added in situ training for teaching safety skills to prevent gun play. Following baseline, each child received two sessions of behavioral skills training and one in situ training session. Additional in situ training sessions were conducted until the child exhibited the safety skills (don't touch the gun, get away, and tell an adult). All children acquired and maintained the safety skills at a 3-month follow-up. In addition, of the 7 children assessed in a dyad situation, all exhibited the correct skills in the presence of another child.     

Structural equation models for interchangeable dyads: being the same makes a difference

Structural equation modeling (SEM) offers a flexible method for studying the patterns of interdependence in partners' behavior, which lie at the heart of interactions and relationships. Although SEM has been applied to the study of distinguishable dyads, in which partners are distinguishable by type, such as male and female, it has rarely been applied to the study of interchangeable dyads, such as male-male or female-female pairs. The authors integrate a wide range of dyadic interdependence models--including actor-partner interdependence models, mutual-influence models, and common-fate or dyadic personality models--into an SEM framework for use with interchangeable dyads. The authors also address the use of latent variables at both the dyadic and individual levels, whereby substantive relationships in these models can be corrected for errors of measurement. Furthermore, the authors discuss the conceptual underpinnings of dyadic models and give examples of their application.     

Parents, peers, and problem behavior: a longitudinal investigation of the impact of relationship perceptions and characteristics on the development of adolescent problem behavior

This study examined longitudinal relations among adolescents' family relationships, peer relationships, and problem behavior. Participants were 1,357 African American and European American adolescents who were interviewed at 3 time points: 7th grade (mean age = 12.7 years), the summer after 8th grade (mean age = 14.2 years), and 11th grade (mean age = 17.1 years). For all racial and gender groups, 7th-grade family characteristics (youth perceptions of autonomy and warmth) predicted a risky peer context during 8th grade, which in turn predicted problem behavior during 11th grade. Additionally, problem behavior in the 7th grade predicted 11th-grade problem behavior, directly as well as indirectly through the peer context. Racial and gender differences are discussed, as are implications for future research.     

Analysis of response repetition as an error-correction strategy during sight-word reading

A great deal is known about the effects of positive reinforcement on response acquisition; by contrast, much less research has been conducted on contingencies applied to errors. We examined the effects of response repetition as an error-correction procedure on the sight-word reading performance of 11 adults with developmental disabilities. Study 1 compared single-response (SR) repetition and multiple-response (MR) repetition, and results showed that all 6 participants acquired more sight words with the MR procedure. Study 2 compared MR error correction following every incorrect response (continuous) and following one third of incorrect responses (intermittent), and results showed that all 6 participants acquired more sight words when error correction was continuous. Study 3 compared MR error correction in which errors required practice of the training word (relevant) versus a different word (irrelevant), and results showed that 3 of 9 participants showed better performance under the relevant condition; however, all participants showed improvement even under the irrelevant condition. Findings are discussed in terms of the behavioral processes by which error correction may enhance performance during acquisition.