The development of stimulus control with and without a lighted key

In two experiments, the effect of an illuminated response key on the acquisition of stimulus control by an airflow stimulus was assessed. In the first experiment, pigeons were given nondifferential training with airflow emerging from behind the response key in one of three conditions of illumination: trained to peck a lighted key, trained to peck an unlighted key with a houselight present, trained to peck a key in total darkness. After 10 days of training on a variable-interval schedule of reinforcement, all subjects were given a generalization test on airflow velocity. The gradients for subjects trained in the dark were sharp, while those for subjects trained in lighted conditions were shallow. In the second experiment, the effect of an irrelevant keylight on the acquisition of an airflow velocity discrimination was assessed. Two groups of pigeons were trained to discriminate two airflow velocities. One group was trained with a lighted response key and the other was trained to peck the response key in total darkness. The dark-trained subjects acquired the discrimination more rapidly. The results demonstrate that the acquisition of stimulus control by airflow with either a differential or nondifferential training procedure can be overshadowed by keylight.     

Agricultural policy and strategic investment in information technology

In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.     

Order effects in belief updating with consistent and inconsistent evidence

The current study tests for the presence of differential order effects in evaluation tasks with consistent and inconsistent evidence as predicted by the Hogarth and Einhorn (1992) belief-adjustment model. The results, based on both between-subjects and within-subjects experiments, demonstrate that there were significant recency effects with inconsistent evidence as predicted, larger recency effects when the inconsistent evidence was farther apart in subjective value as predicted, and significant recency effects even when subjects were given training designed to both help them understand the task as completely as possible and to be better able to assess the pieces of evidence. By including a within-subjects design, we were able to demonstrate that the difference in subjective value between two pieces of evidence is the primary factor influencing the magnitude of the recency effect, regardless of whether the evidence is consistent or inconsistent. This latter finding is unique and contrary to previous research and theory.     

Procedural fairness and self-esteem

We argue that people's self-esteem is affected by the fairness of procedures to which they are subjected; unfair treatment will lower self-esteem. Moreover, since this influence on self-esteem is presumably due to the implicit evaluation expressed by the choice of procedure and hence by the evaluation expressed by the person implementing the procedure, people's concern with the fairness of treatment will be focused on the interactional aspects of the procedure. In two experiments designed to test these hypotheses subjects received either a high or a low grade on an ability test on the basis of either fair or unfair grading procedures. The results of Experiment 1 indicated that subjects' self-esteem was lower after unfair treatment, and this influence was only apparent when subjects received high test feedback. Additionally, ratings of the fairness of the interaction were lower following unfair grading procedures. Experiment 2 also manipulated level of involvement with the test. Self-esteem was affected by procedural fairness and procedural fairness influenced perceived fairness of the interaction only in the high involvement condition.     

Racial bias and the MCMI

We studied the scores obtained on the Millon Clinical Multiaxial Inventory (MCMI) by Black and White male psychiatric inpatients to determine the presence or absence of racial bias. In predicting psychopathology for the two races, comparisons of MCMI performance indicated significant differences for all diagnoses except the personality disorders. The subjects were then matched into two groups of 209 patients each, according to DSM-III psychiatric diagnoses. The data were analyzed at the item, scale, and structural levels. At the item level, application of the Mantel-Haenszel Procedure revealed that 45 of the 175 items of the inventory were answered significantly different by the two racial groups. Because this number was higher than what could be expected by chance, the finding suggested possible deficiencies in terms of the culture-fairness of the items used in the test. At the scale level, an analysis of variance (ANOVA) demonstrated that the scores obtained by the Black and White groups were significantly different in 9 of the 20 scales (Histrionic, Narcissistic, Antisocial, Paraphrenia, Hypomania, Dysthymia, Alcohol Abuse, Drug Abuse, and Psychotic Delusion). With the exception of the Dysthymic scale, all of the differences were in the direction of the Blacks obtaining a higher score than the Whites. At the structural level, however, a principal components factor analysis performed on each group resulted in factor structures that looked identical.     

An on-line assessment of causal reasoning during comprehension

Fletcher and Bloom (1988) have argued that as readers read narratives, clause by clause, they repeatedly focus their attention on the last preceding clause that contains antecedents but no consequences in the text. This strategy allows them to discover a causal path linking the text's opening to its final outcome while minimizing the number of times long-term memory must be searched for missing antecedents or consequences. In order to test this hypothesis, we examined the reading times of 25 subjects for each clause of eight simple narrative texts. The results show that: (1) causal links between clauses that co-occur in short-term memory (as predicted by the strategy) increase the time required to read the second clause; (2) potential causal links between clauses that never co-occur in short-term memory (again as predicted by the strategy) have no effect on reading time; and (3) reinstatement searches are initiated at the end of sentences that are causally unrelated to the contents of short-term memory or that contain clauses that satisfy goals no longer in short-term memory. These results support the claim that subjects engage in a form of causal reasoning when they read simple narrative texts.     

Location errors in partial-report bar-probe experiments: In search of the origin of cue-alignment problems

In studies using Averbach and Coriell’s (1961) partial-report bar-probe paradigm with linear arrays, most errors involve the naming of an item that was in the display but in a position other than the cued one. Up to now, there is no general agreement on the origin of these location errors. Point of departure in this paper is that part of the location errors arises from inappropriate application of the cue. It is tested whether this originates from problems to perceive the position of the cue (“cue-displacement hypothesis”) or from confusion about the order of the items in the array (“item-order hypothesis”). The results of two bar-probe experiments are reported. A novel, crucial, finding in both experiments is that, among the location errors, there was a preponderance of response letters that came from the central side of the cued item. In the second experiment, this was observed not only in the usual postcue conditions but also when the cue preceded the array. These results positively corroborate the cue-displacement hypothesis and do not support the item-order hypothesis: The cue tends to be perceived more toward the center of the visual field than it actually is exposed—that is, there is a central drift of the cue.