Detecting a nonevent: Delayed presence-versus-absence discrimination in pigeons

Eight pigeons were trained on a delayed presence-versus-absence discrimination paradigm in which a sample stimulus was presented on some trials but not on others. If a sample was presented, then a response to one choice key produced food. If no sample was presented, a response to the other choice key produced food. The basic finding was that performance remained constant and well above 50% correct on no-sample trials as the retention interval increased, whereas performance dropped precipitously (to below 50% correct) on sample trials. In the second phase of the experiment, all of the trials were no-sample trials, and reinforcers were delivered probabilistically for one group of pigeons and according to time-based schedules for the other group. The exact reinforcement probabilities used in Phase 2 were those calculated to be in effect on no-sample trials in Phase 1 (according to a discrete-state model of performance). Subjects did not show exclusive preference for the richer alternative on no-sample trials in the first phase, but those in the probabilistic group developed near-exclusive preference for the richer alternative during the second phase. These data are inconsistent with the predictions of the discrete-state model, but are easily accommodated by an account based on signal detection theory, which also can be applied effectively to discrimination of event duration and the “subjective shortening” effect.     

Semilattice-based dualities

The paper discusses regularisation of dualities. A given duality between (concrete) categories, e.g. a variety of algebras and a category of representation spaces, is lifted to a duality between the respective categories of semilattice representations in the category of algebras and the category of spaces. In particular, this gives duality for the regularisation of an irregular variety that has a duality. If the type of the variety includes constants, then the regularisation depends critically on the location or absence of constants within the defining identities. The role of schizophrenic objects is discussed, and a number of applications are given. Among these applications are different forms of regularisation of Priestley, Stone and Pontryagin dualities.     

Individual and age-related differences in children’s working memory

The purpose of this study was to investigate the degree to which age-related and individual differences in children’s working memory (WM) are due to a general or task-specific capacity system. Experiment 1 correlated children’s (N=146; age range 5–19 years) verbal and visual-spatial working memory performance with various intelligence and achievement measures. The results supporting a general system were that (1) visual-spatial and verbal WM measures were significantly intercorrelated with and without age partialed out and (2) both verbal and visual-spatial WM measures were significantly correlated with diverse achievement and intelligence measures. Experiment 2 compared three age groups (N=192; 7-, 10-, and 13-year-olds) on working-memory performance tasks under initial, enhanced (cued), and maintenance conditions. The results supporting a general capacity system were that (1) age-related performance differences in WM were found on all conditions and not isolated to specific processes, (2) the maintenance measures (high-load condition) predicted the variance better in age-related performance than process measures, and (3) although individual differences in WM performance reflected two independent operations, these operations produced similar correlations to achievement within age groups. Overall, the results support a general capacity explanation of age-related and individual differences in children’s WM performance.     

Group aggregates and individual reliability: The case of verbal short-term memory

Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally, an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.     

Prosodic influences on the resolution of temporary ambiguity during on-line sentence processing

We present three experiments designed to investigate the role of prosody during sentence processing. The first investigated the question of whether an utterance's prosodic contour influences its comprehension on-line. We spliced the beginning and end portions of direct object and embedded clause sentences and observed the consequent effects on comprehension using a dual-task procedure to measure processing load. Our second experiment sought to determine-whether the constituent structure of these sentences could be reliably predicted using prosodic information. We found that the duration and F₀ contour associated with the main-clause verb and the following NP reliably distinguished between the direct object and embedded clause constructions. In the final experiment, we manipulated the duration of the main-clause verb and found that subjects used this information to guide their initial parse during on-line sentence comprehension. The need for a model of sentence processing that addresses the use of prosodic information is discussed.The work reported in this paper was supported in part by NTH grant DC00494.     

Social-Cognitive and Behavioral Correlates of Aggression and Victimization in Boys' Play Groups

A contrived play group procedure was utilized to examine the behavioral and social-cognitive correlates of reactive aggression, proactive aggression, and victimization via peers. Eleven play groups, each of which consisted of six familiar African-American 8-year-old boys, met for 45-min sessions on five consecutive days. Social-cognitive interviews were conducted following the second and fourth sessions. Play group interactions were videotaped and examined by trained observers. High rates of proactive aggression were associated with positive outcome expectancies for aggression/assertion, frequent displays of assertive social behavior, and low rates of submissive behavior. Reactive aggression was associated with hostile attributional tendencies and frequent victimization by peers. Victimization was associated with submissive behavior, hostile attributional bias, reactive aggression, and negative outcome expectations for aggression/assertion. These results demonstrate that there is a theoretically coherent and empirically distinct set of correlates associated with each of the examined aggression subtypes, and with victimization by peers.     

Measuring How We Preach What We Practice: Psychoeducational Change in Depressed Inpatients

This study investigated the relationship between acquisition of psychoeducational principles and symptomatic improvement in depressed in-patients. One hundred and twenty-three inpatients hospitalized on a Cognitive Therapy Unit were administered the Test of Cognitive Behavioral Principles (TCBP) and the Beck Depression Inventory at admission and discharge. It was predicted that the TCBP scores would be higher at discharge than at pre-testing at admission. Further, it was hypothesized that the higher TCBP scores at post-test would be significantly correlated with lower Beck Depression Inventory scores at post-test. The results revealed that inpatients' TCBP scores improved over the course of treatment supporting the first hypothesis. However, the data did not support the second hypothesis as there was not a significant relationship between the TCBP scores and the BDI scores at discharge. The results are discussed in terms of clinical, theoretical, and methodological implications.     

Effects of Self-Appraisal Information, Appraisal Purpose, and Feedback Target on Performance Appraisal Ratings

This experiment investigated the effects of three factors on performance appraisal ratings: self-appraisal information, appraisal purpose, and feedback target. Two hundred and three subjects rated a subordinate's performance on a clerical task subsequent to receiving either a high or low self-assessment. They were told they would provide performance feedback either to the experimenter (organizational agent) or their subordinate, and their ratings would be used either for an administrative decision or developmental feedback. Performance ratings were significantly higher when subjects received a favorable subordinate self-assessment than when self-assessments were unfavorable. A significant interaction was found between feedback target and the appraisal purpose. Implications for the use of self-appraisals in organizations were discussed.     

When More is Better than Less; Three Theories of Psychosis—Projection, Double Bind, and Possession

Three psychological theories of psychosis are described, each of which has standing in psychiatry. Defined by the terms projection, double bind, and possession, they initially appear to have little or nothing in common to explain psychosis, but converge at four points: (1) A high degree of anxiety precipitated by a dilemma or conflict perceived to be unsolvable by the person; (2) the anxiety triggers a shift from one thought or motive in the direction of its opposite, because the original was believed too antagonistic to the wishes of significant others; (3) the opposite, in order to remain opposite, requires that the original thought or motive be forgotten, (4) a singular means to produce and reinforce forgetting is the interposition of psychiatric symptoms. In psychiatry today treatment would fit more consistently with the three theories taken as a whole rather than any one, and a rationale for this viewpoint is elaborated.     

A Social Dilemma Analysis of Commuting Preferences: The Roles of Social Value Orientation and Trust1

The current research advances a social dilemma analysis of commuting, examining the roles of preexisting personality differences in social value orientation (i.e., prosocial vs. proself orientation) and trust (i.e., a general belief in the honesty and cooperative intentions of others) in determining preferences for collectively desirable commuting options: preferences for commuting by public transportation (Study 1) and carpooling (Study 2). Consistent with predictions, both studies revealed that, relative to p of prosocials, preferences of proselfs were more strongly associated with beliefs about the relative efficiency of cars (i.e., an outcome affecting personal well-being). Also, greater preferences for collectively desirable actions were observed among prosocials with high trust—relative to prosocials with low trust and proselfs with high or low trust—providing support for the claim that 2 conditions (i.e., prosocial goals and trust in others) must be met to obtain collectively desirable commuting preferences.