Brief presentations are sufficient for pigeons to discriminate arrays of same and different stimuli

Four pigeons first learned to discriminate 16-item arrays of same from different pictorial stimuli. They were then tested with reduced exposure to the pictorial arrays, brought about by changes in the stimulus viewing requirement under fixed-ratio (FR) and fixed-interval (FI) schedules. Increasing the FR requirement enhanced discriminative performance up to 10 pecks; increasing the FI requirement enhanced discriminative performance up to 5 s. Exposures to the stimulus arrays averaging only 2 s supported reliable discrimination. Pigeons thus discriminate same from different stimuli with considerable speed, suggesting that same-different discrimination behavior is of substantial adaptive significance.     

The development of emergent differential sample behavior in pigeons

Three experiments attempted to replicate Manabe, Kawashima, and Staddon's (1995) finding of emergent differential sample behavior in budgerigars that has been interpreted as evidence of functional equivalence class formation. In Experiments 1 and 2, pigeons initially learned two-sample/ two-alternative matching to sample in which comparison presentation was contingent on pecking one sample on a differential-reinforcement-of-low-rate (DRL) schedule and the other on a fixed-ratio (FR) schedule. Later, two new samples were added to the task. Comparison presentation on these trials occurred after the first sample peck following a predetermined interval (Experiment 1) or after completion of either the DRL or FR requirement, whichever occurred first (Experiment 2). Experiment 1 found no evidence for emergent spaced versus rapid responding to the new samples as they established conditional control over the familiar choices. By contrast, differential responding did emerge for some pigeons in Experiment 2, with responding to each new sample coinciding with the pattern explicitly conditioned to the original sample occasioning the same comparison choice. This emergent effect, however, disappeared for most pigeons with continued training. Experiment 3 systematically replicated Experiment 2 using differential peck location as the sample behavior. Differential location pecking emerged to the new samples for most pigeons and remained intact throughout training. Our findings demonstrate a viable pigeon analogue to the budgerigar emergent calling paradigm and are discussed in terms of equivalence- and non-equivalence-based processes.     

Asymptotic identifiability of nonparametric item response models

The identifiability of item response models with nonparametrically specified item characteristic curves is considered. Strict identifiability is achieved, with a fixed latent trait distribution, when only a single set of item characteristic curves can possibly generate the manifest distribution of the item responses. When item characteristic curves belong to a very general class, this property cannot be achieved. However, for assessments with many items, it is shown that all models for the manifest distribution have item characteristic curves that are very near one another and pointwise differences between them converge to zero at all values of the latent trait as the number of items increases. An upper bound for the rate at which this convergence takes place is given. The main result provides theoretical support to the practice of nonparametric item response modeling, by showing that models for long assessments have the property of asymptotic identifiability. The research was partially supported by the National Institute of Health grant R01 CA81068-01.     

Community-driven learning activities,creating futures: 30,000 people can't be wrong—Can they?

A major vehicle for the practice of community psychology is through the organization of community-based activities. My colleagues and I have developed many programs for community learning centers, in-school and after school programs, and community technology centers. In the last 10 years, 30,000 people (mostly children) have participated in activities designed for enjoyment and learning, with a view to adding protective factors and reducing negative factors in at-risk communities. Development of these programs for literacy, education, life and work skills, has increasingly followed a community responsive model. Within each program, we created explicit images of future success. That is, people could see themselves being successful where they normally fail: self modeling with feedforward. Data reports show that individuals generalized and maintained their new skills and attitudes, but the sustainability of programs has been variable. Analysis of the variations indicates the importance of program level feedforward that brings the future into the present. The discussion includes consideration of how individual-level and community-level practices can inform each other. Author Note: Aspects of this article have been presented at the 10th Trans-Tasman Community Psychology Conference, Sydney, April 2006, and in an invited address at the 114th annual convention of the American Psychological Association, New Orleans, August 2006. Partial support in the preparation of this paper was provided by mutliple grants from the US Department of Education, although no endorsement is implied.     

The Ecology of Adolescent Substance Abuse Service Utilization

This paper presents an ecological-community model toward the explanation of variation in patterns of substance abuse (SA) service utilization among adolescents who are enrolled in Tennessee's Medicaid program (TennCare). Guided by a theoretical framework that draws from the social ecology work of Bronfenbrenner and health services utilization models promoted by Aday and Andersen, we apply a social indicators approach toward explaining the impact of community ecology on identification of SA and treatment engagement. Both county-level rates and individual-level treatment utilization are examined and hierarchical linear modeling is incorporated to examine the individual-in-community phenomenon. This study is an expansion of previous service utilization research and suggests that explanations of youth's service utilization must necessarily include not only individual, familial, and service system characteristics, but community factors, as well.     

Validity of Treatment Target Progress Ratings as Indicators of Youth Improvement

We examined whether clinical progress ratings on the Monthly Treatment and Progress Summary form (MTPS), an idiographic treatment progress measure, were meaningfully related to changes measured by two separate standardized instruments; the Child and Adolescent Functional Assessment Scale (CAFAS) and the Child and Adolescent Level of Care Utilization System (CALOCUS). Validity coefficients were examined at intake and three-, six-, and nine-month follow-up periods. Samples were selected for each measure and follow-up period from the population of youth receiving services through the Hawaii Child and Adolescent Mental Health Division’s (CAMHD) system of care. Significant youth improvement was evident on all three measures across all follow-up intervals. The type of changes measured by the MTPS and CAFAS were more alike over longer follow-up intervals than changes measured by the CALOCUS. The MTPS captures distinct aspects of client change that overlaps somewhat with CAFAS and CALOCUS measures. The MTPS is a brief client-tailored measure that seems to provide valid, sensitive, and nonredundant client specific treatment outcome information that can be collected on a frequent basis within a complex system of care.     

Family Empowerment as a Mediator between Family-Centered Systems of Care and Changes in Child Functioning: Identifying an Important Mechanism of Change

We investigated the associations among perceived fidelity to family-centered systems of care, family empowerment, and improvements in children's problem behaviors. Participants included 79 families, interviewed at two time points across a one-year period. Paired samples t-tests indicated that problem behaviors decreased significantly across a one-year period. Hierarchical multiple regressions indicated that both fidelity to family-centered systems of care and family empowerment independently predicted positive change in children's problem behavior over a one-year period. However, when family empowerment is entered first in the regression, the relationship between fidelity to family-centered systems of care and change in children's problem behavior drops out, indicating that family empowerment mediates the relationship between family-centered care and positive changes in problem behaviors. Consistent with other literature on help-giving practices, family empowerment appears to be an important mechanism of change within the system of care philosophy of service delivery. Implications for practice and staff training are discussed.     

Traumatic loss and major disasters: strengthening family and community resilience

This article presents the core principles and value of a family and community resilience-oriented approach to recovery from traumatic loss when catastrophic events occur. In contrast to individually based, symptom-focused approaches to trauma recovery, this multisystemic practice approach contextualizes the distress in the traumatic experience and taps strengths and resources in relational networks to foster healing and posttraumatic growth. The intertwining of trauma and traumatic losses is discussed. Key family and social processes in risk and resilience in traumatic loss situations are outlined. Case illustrations, model programs, and intervention guidelines are described in situations of community violence and major disasters to suggest ways to foster family and community resilience.     

Conditional relations with compound abstract stimuli using a go/no-go procedure

The aim of this study was to evaluate whether emergent conditional relations could be established with a go/no-go procedure using compound abstract stimuli. The procedure was conducted with 6 adult humans. During training, responses emitted in the presence of certain stimulus compounds (A1B1, A2B2, A3B3, B1C1, B2C2, and B3C3) were followed by reinforcing consequences (points); responses emitted in the presence of other compounds (A1B2, A1B3, A2B1, A2B3, A3B1, A3B2, B1C2, B1C3, B2C1, B2C3, B3C1 and B3C2) were not (i.e., extinction). During subsequent tests of emergent relations, new configurations (BA, CB, AC, and CA relations) were presented, formed by the recombination of training stimuli and structurally resembling tests usually employed in stimulus equivalence studies. Results showed that all 6 participants displayed immediate emergence of relations consistent with symmetry. Four participants exhibited emergent relations consistent with both transitivity and equivalence. These results indicate that a go/no-go procedure with compound stimuli can establish emergent conditional relations, thus providing a procedural alternative to the matching-to-sample procedures commonly used in studies of stimulus equivalence.     

Naming and categorization in young children: v. manual sign training

Following pre-training with everyday objects, 8 children aged from 2 to 4 years learned to produce one manual sign (fists placed one above the other, in front of body) to one stimulus and an alternative manual sign (shoulders touched with ipsilateral hands) to the other stimulus, with each of three pairs of different arbitrary wooden shapes (Set 1). The six stimuli then were presented in category match-to-sample tests, which all subjects passed. Three of the children were next trained to produce the manual signs (denoted as fist/shoulder) for an additional six arbitrary stimuli, Set 2. All 3 children went on to pass category match-to-sample tests for Set 2, and for Set 1 and Set 2 combined. In the final experimental phase, 2 of the children were trained, for one of the six stimulus pairs, to produce the vocal tact "zag" to one stimulus and "vek" to the other. Both children showed category transfer of these vocalizations in test trials with each of the remaining five stimulus pairs, and all the stimuli combined in a 12-stimulus array. In line with Horne and Lowe's (1996) naming account, manual sign naming was found to be as effective as vocal naming in establishing arbitrary stimulus categorization, measured in terms of category sorting and transfer of function. The findings also have implications for the training of verbal repertoires in people with learning disabilities.