Rate of conditioned reinforcement affects observing rate but not resistance to change

The effects of rate of conditioned reinforcement on the resistance to change of operant behavior have not been examined. In addition, the effects of rate of conditioned reinforcement on the rate of observing have not been adequately examined. In two experiments, a multiple schedule of observing-response procedures was used to examine the effects of rate of conditioned reinforcement on observing rates and resistance to change. In a rich component, observing responses produced a higher frequency of stimuli correlated with alternating periods of random-interval schedule primary reinforcement or extinction. In a lean component, observing responses produced similar schedule-correlated stimuli but at a lower frequency. The rate of primary reinforcement in both components was the same. In Experiment 1, a 4:1 ratio of stimulus production was arranged by the rich and lean components. In Experiment 2, the ratio of stimulus production rates was increased to 6:1. In both experiments, observing rates were higher in the rich component than in the lean component. Disruptions in observing produced by presession feeding, extinction of observing responses, and response-independent food deliveries during intercomponent intervals usually were similar in the rich and lean components. When differences in resistance to change did occur, observing tended to be more resistant to change in the lean component. If resistance to change is accepted as a more appropriate measure of response strength than absolute response rates, then the present results provide no evidence that higher rates of stimuli generally considered to function as conditioned reinforcers engender greater response strength.     

Neural correlates of a default response in a delayed go/no-go task

Working memory, the ability to temporarily retain task-relevant information across a delay, is frequently investigated using delayed matching-to-sample (DMTS) or delayed Go/No-Go tasks (DGNG). In DMTS tasks, sample cues instruct the animal which type of response has to be executed at the end of a delay. Typically, performance decreases with increasing delay duration, indicating that working memory fades across a delay. However, no such performance decrease has been found when the sample cues exist of present vs. absent stimuli, suggesting that pigeons do not rely on working memory, but seem to respond by default in those trials. We trained 3 pigeons in a DGNG task and found a similar default response pattern: The diverging slopes of the retention functions on correct Go and No-Go trials suggested that pigeons by default omitted their response following No-Go stimuli, but actively retained task-relevant information across the delay for successful responses on Go trials. We conducted single-cell recordings in the avian nidopallium caudolaterale, a structure comparable to the mammalian prefrontal cortex. On Go trials, many neurons displayed sustained elevated activity during the delay preceding the response, replicating previous findings and suggesting that task-relevant information was neurally represented and maintained across the delay. However, the same units did not show enhanced delay activity preceding correct response suppressions in No-Go trials. This activation-inactivation pattern presumably constitutes a neural correlate of the default response strategy observed in the DGNG task.     

On the effects of signaling reinforcer probability and magnitude in delayed matching to sample

Two experiments examined whether postsample signals of reinforcer probability or magnitude affected the accuracy of delayed matching to sample in pigeons. On each trial, red or green choice responses that matched red or green stimuli seen shortly before a variable retention interval were reinforced with wheat access. In Experiment 1, the reinforcer probability was either 0.2 or 1.0 for both red and green responses. Reinforcer probability was signaled by line or cross symbols that appeared after the sample had been presented. In Experiment 2, all correct responses were reinforced, and the signaled reinforcer durations were 1.0 s and 4.5 s. Matching was more accurate when larger or more probable reinforcers were signaled, independently of retention interval duration. Because signals were presented postsample, the effects were not the result of differential attention to the sample.     

The Middle Passage,Trauma and the Tragic Re-Imagination of African American Theology

African American Christian consciousness developed in response to the traumatic field in which African American subjectivity took shape. The expression of the faith in the African American tradition is fundamentally tragic as a consequence. The Middle Passage is the existential and symbolic nodal point of this experience. There is a sense in which African Americans remain very much on the water; marginalized and suspended between worlds. There is a deeper sense in which the African American situation and response reflects the condition of modernity and post-modernity in the sense that it is hardly more than modernity becoming conscious of itself. A thorough examination and exploration of its significance is essential to developing a theology that adequately expresses African American Christian consciousness. This paper is an attempt to lay out, what I think, are some of the basic components of the experience and the bare outlines or orientation of such a theology grounded in it.     

Time trends in the adjustment of Swedish teenage girls: a 26-year comparison of 15-year-olds

The aim of this study was to investigate stability and change over 26 years in self-reported adjustment of Swedish teenage girls. Data were collected with the same questionnaire from two school-cohorts in a middle-sized Swedish community: 522 girls attending Grade 8 (approximately at age 15) in 1970, and 529 girls attending Grade 8 in 1996. The first cohort was part of the longitudinal research programme Individual Development and Adaptation (IDA). In most domains, adjustment problems were approximately as common in 1996 as in 1970, with two exceptions: more girls reported problems with self-esteem and antisocial problems in 1996. In the antisocial domain, a polarization process was indicated, with an increase also in the number of girls without adjustment problems. In the relational domains, especially peer relations, there was an increase in positive adjustment. The results are discussed in relation to earlier findings and to social changes during the period.     

Communication flow and change theory within a family therapy supervision model

This article portrays a model of family therapy clinical supervision using change theory that is most appropriate for use with the videotape, audiotape, case presentation and debriefing from the live session. The most powerful tool during this process is that of communication and assessment of change theorys tools of confidence and conviction. The concepts presented are meant to add an additional dimension to family therapy supervision in cooperation of other theories, not as an end in themselves.Special thanks to Ms. Geri Koncilja of the Informational Technology Center at Colorado State University, Pueblo for illustration and graphic assistance.     

"结构":解读古典经济学哲学构架的逻辑中轴--瓦尔特·本雅明:作品、生活、时代和历史的交叠

马克思的"古典经济学"概念具有明确内涵、外延并与一定的"知识型"相关,这与西方学者在一般的、含糊的意义使用这个概念具有根本的异质性.它界划了一种分析的范式,说明了马克思与资产阶级经济学之间存在着"知识型"的断裂,这种分析范式就是从配第和布阿吉尔贝尔开始的探讨社会结构及由这种结构所决定的运动规律,这是"古典经济学"概念之独特内涵所在.福柯等人忽视了古典经济学的"结构"视角而从"劳动"范畴出发,认为马克思对李嘉图的修正在西方知识的最深层中并未产生真正的间断性,这是没有读懂马克思"古典政治经济学"的真正内涵.     

Heart Follows Head: Influencing Violence-related Attitudes in the Classroom

We examined whether an undergraduate course on violence would influence students’ violence-related attitudes and beliefs. Students (N=145) completed the Violence-Related Attitudes and Beliefs Scale (V-RABS) at the beginning (Time 1) and end (Time 2) of the semester-long course. As expected, support for the death penalty, punishment, and catharsis decreased significantly, as did belief in an association between mental illness and violence. Acceptance of environmental influences on violent behavior increased significantly, although belief in biological influences did not change. Support for violence prevention efforts was high at both Times 1 and 2, and did not change significantly. Consistent with previous research, the results of this study confirm that college curricula may influence students’ attitudes and beliefs in addition to imparting knowledge.     

Academic Self-Schemas and their Self-Congruent Learning Patterns: Findings Verified with Culturally Different Samples

This paper reported two studies investigating high school students’ academic self-schemas in learning mathematics and their self-congruent learning engagement patterns. Using cluster analyses, Study 1 located two contrasting groups of students holding positive and negative self-schemas in learning mathematics among Chinese participants. MANOVA analyses showed that these two groups of Chinese schematic students differed from each other in the use of achievement goals, approaches to learning, and expected levels of performance. These findings were validated and extended in Study 2 using a culturally different sample, Australian students. Again, cluster analyses successfully classified Australian participants into positive and negative schematic clusters. It was also found that these two groups of schematic students approached learning mathematics in a self-congruent manner similar to those found in Study 1. The converging results in both studies lent empirical support to the theoretical formulation of positive and negative schematic students and the validity of using the self-schema concept to investigate motivation and learning. The differences in their learning engagement patterns were discussed in terms of students’ different academic self-schemas in learning mathematics.     

Religious Activity and Risk Behavior Among African American Adolescents: Concurrent and Developmental Effects

This study examines how religious activity is associated with risk behaviors, concurrently and developmentally among urban African American adolescents. Seven hundred and five African American youths were interviewed annually during high school. Retention rates for the study exceeded 90%. Frequency of religious activity, sexual intercourse, and alcohol, cigarette, and marijuana use were assessed at each wave. Growth curve analyses found negative concurrent associations between religious activity and each of the four risk behaviors. The developmental effects of religious activity varied by gender. Higher levels of religious activity in 9th grade predicted smaller increases in marijuana use among males and cigarette use among females. In addition, larger decreases in religious activity during high school were associated with greater increases in alcohol use among males and sexual intercourse among females. During high school, religious activity limits the development of certain types of risk behavior among African American youth, even after controlling for reciprocal effects.