Tests of the ratio rule in categorization.

Many theories of learning and memory (e.g., connectionist, associative, rational, exemplar based) produce psychological magnitude terms as output (i.e., numbers representing the momentary level of some subjective property). Many theories assume that these numbers may be translated into choice probabilities via the ratio rule, also known as the choice axiom (Luce, 1959) or the constant-ratio rule (Clarke, 1957). We present two categorization experiments employing artificial, visual, prototype-structured stimuli constructed from 12 symbols positioned on a grid. The ratio rule is shown to be incorrect for these experiments, given the assumption that the magnitude terms for each category are univariate functions of the number of category-appropriate symbols contained in the presented stimulus. A connectionist winner-take-all model of categorical decision (Wills & McLaren, 1997) is shown to account for our data given the same assumption. The central feature underlying the success of this model is the assumption that categorical decisions are based on a Thurstonian choice process (Thurstone, 1927, Case V) whose noise distribution is not double exponential in form.     

Reducing Time-Out Assignments for Students with Emotional/Behavioral Disorders in a Self-Contained Classroom

This study assessed the impact of a class-wide time-out/re-directing strategy on (a) the frequency of teacher-assigned time-outs and (b) the time students spent in disciplinary sanctions. Twelve students with emotional/behavioral disorders, enrolled in a self-contained elementary classroom were taught an alternative time-out strategy (Active Response Beads-Time Out), while teachers were taught a re-directing strategy, in an attempt to decrease the amount of student's time spent in time-out (TO) and the number of TO assigned by staff. Using a multiple baseline design across academic classroom periods, results showed that Active Response Beads Time-Out (ARB-TO) and teacher re-directions decreased the total time spent in time-out and number of TO assigned across the three class periods. Results maintained at one, two and four week follow-up sessions.     

Emotional distress in nonmetropolitan persons living with HIV disease enrolled in a telephone-delivered, coping improvement group intervention.

The study delineated depressive symptoms and modeled emotional distress in persons living with HIV disease in nonmetropolitan areas of 13 U.S. states. Participants (N=329) were enrolled in a randomized clinical trial of a telephone-delivered, coping improvement group intervention, and 60% reported moderate or severe levels of depressive symptomatology on the Beck Depression Inventory. Structural equation modeling indicated that participants who experienced more severe HIV symptomatology, received less social support, and engaged in more avoidant coping also experienced more emotional distress (a latent construct comprising depressive symptoms and emotional well-being). Greater HIV-related stigma and rejection by family led to more emotional distress, with social support and avoidant coping mediating almost entirely the effects of the former 2 variables. The model accounted for 72% of the variance in emotional distress in nonmetropolitan persons living with HIV disease.     

American Indian Youth: Who Southwestern Urban and Reservation Youth Turn to for Help with Mental Health or Addictions

We illustrate the addictions and mental health service use of American Indian adolescents. Interviews concerning mental health need and service configurations with 401 Southwestern American Indian (AI) youth used questions from the Diagnostic Interview Schedule (DIS) and the Service Assessment for Children and Adolescents (SACA). Seventy-nine percent had mental health or addiction problems, with half meeting criteria for at least one diagnosis. One in 4 youth met criteria for drug dependence'abuse or conduct disorder, 1 in 5 for depression, and 1 in 8 for alcohol dependence'abuse. Most youth were helped by a combination of providers. Youth meeting more diagnostic criteria were increasingly likely to use service configurations with adults, nonspecialist professionals, and specialists, respectively. Regardless of disorder, youth were least likely to use configurations with traditional healers or specialists and there was little difference in rates of use between the two. The lack of services from specialist providers was potentially offset by use of an extensive range of informal adults, nonspecialist professionals, and peers. Since informal helpers, peers, and nonspecialist providers, but not specialists, are providing the bulk of services they must be given support and skills so they can function effectively.     

Patients with bipolar disorder show a selective deficit in the episodic simulation of future events

A substantial body of evidence suggests that autobiographical recollection and simulation of future happenings activate a shared neural network. Many of the neural regions implicated in this network are affected in patients with bipolar disorder (BD), showing altered metabolic functioning and/or structural volume abnormalities. Studies of autobiographical recall in BD reveal overgeneralization, where autobiographical memory comprises primarily factual or repeated information as opposed to details specific in time and in place and definitive of re-experiencing. To date, no study has examined whether these deficits extend to future event simulation. We examined the ability of patients with BD and controls to imagine positive, negative and neutral future events using a modified version of the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) that allowed for separation of episodic and non-episodic details. Patients were selectively impaired in imagining future positive, negative, and neutral episodic details; simulation of non-episodic details was equivalent across groups.     

Age, gender, and reasons for living among Australian adults

Reasons for living have been identified as protective factors in relation to suicide, and much research has documented gender differences in reasons for living. In contrast, little research has investigated age differences in reasons for living. In the current study, the relationship of age to reasons for living was investigated, as was whether age and gender interact to influence reasons for living. A community sample of Australian adults (N = 970) aged 18 to 95 years (M = 48.40, SD = 20.85) completed the Reasons for Living Inventory. Results for the main effects indicated that being female was associated with higher total, child-related concerns and fear of suicide (FS) scores, whereas increasing age was associated with higher total, responsibility to family (RF), FS, and moral objections scores. Age and gender interacted to influence RF, FS, and fear of social disapproval. For each of these reasons for living, increasing age was associated with higher scores for men; however, there was no association between age and these reasons for living scores among women. Overall, the results indicate that the influence of age, gender, or the combination of the two varies according to the reason for living being investigated.     

Unraveling Cultural Threads: A Qualitative Study of Culture and Ethnic Identity Among Urban Southwestern American Indian Youth Parents and Elders

We utilized qualitative methods to explore ethnic and cultural identity among urban Southwestern American Indian youth, parents, and elders. Twenty-four respondents ranging in age from approximately 13 to 90 years were interviewed in focus groups divided by age. Six major themes and seventeen sub-themes related to tribal and pan-American Indian ethnic identity were identified. Two important findings emerging from our study were that common ethnic identity constructs can be validated and new identity constructs discovered through qualitative methods. These and other findings suggest the importance of qualitative methods in better understanding cultural and ethnic identity. Of particular significance was the notion that the most salient and relevant identity constructs can be learned from the voices and perspectives of ethnic identity members themselves across generations, age, tribal groups, gender, and reservation and urban residence.     

Associative history affects the associative change undergone by both presented and absent cues in human causal learning

R. A. Rescorla (2000) noted that a number of influential theories of associative learning do not take the associative history of cues (i.e., the prior training that they have received) into account when calculating the associative change undergone by those cues. The authors tested this assumption in a human causal learning paradigm and found associative history to be an important determinant of the learning undergone by cues that are presented on a trial. Moreover, associative history was also found to influence the amount of retrospective revaluation undergone by absent cues. These findings conflict with models of causal learning in which the associative change undergone by an element of a cue compound is governed by a summed error term (e.g., R. A. Rescorla & A. R. Wagner, 1972).     

Suicidal behavior in urban American Indian adolescents: a comparison with reservation youth in a southwestern state

The majority of American Indians live off of reservations, yet research on suicidal behavior in this population overwhelmingly focuses on reservation Indians. This exploratory study interviewed a stratified random sample of 144 urban and 170 reservation American Indian adolescents to compare rates and correlates of suicidal behavior. One fifth of urban youth and one third of reservation youth reported lifetime suicidal ideation, although similar numbers (14%-18%) reported an attempt. Urban youth had fewer psychosocial problems, and in separate multivariate analyses, the groups shared no common correlate of attempted suicide. Different approaches to prevention and treatment may be warranted for urban Indian youth.