Learning nonlinearly separable categories by inference and classification

Previous research suggests that learning categories by classifying new instances highlights information that is useful for discriminating between categories. In contrast, learning categories by making predictive inferences focuses learners on an abstract summary of each category (e.g., the prototype). To test this characterization of classification and inference learning further, the authors evaluated the two learning procedures with nonlinearly separable categories. In contrast to previous research involving cohesive, linearly separable categories, the authors found that it is more difficult to learn nonlinearly separable categories by making inferences about features than it is to learn them by classifying instances. This finding reflects that the prototype of a nonlinearly separable category does not provide a good summary of the category members. The results from this study suggest that having a cohesive category structure is more important for inference than it is for classification.     

The pursuit of Leonardo's constraint

Leonardo da Vinci (1452-1519) identified two stimulus situations that cannot be painted faithfully on a canvas: (a) when two objects are located in the same direction with respect to the painter's head, and (b) when parts of a surface are visible to one eye, but occluded from the other eye. He analysed these situations in terms of rays being emitted from the two eyes and, aside from the origin of the rays, the projective geometry he used was correct. His analyses showed that what can be seen from two vantage points cannot be represented on a canvas, because a 'correct' painting must be created from a single 'station point'. He was struck by the consequence of this fact that the depth seen on a canvas cannot match that of viewing the scene with two eyes. Subsequent visual scientists focused on Leonardo's observation about the lack of vivid depth in a picture. We argue that a complete understanding of what we see in the two stimulus situations requires consideration of visual direction in addition to visual depth. More specifically, we argue that the visual directions of the two objects, (a) above, and the visual direction of the monocular areas, (b) above, are dependent upon the constraint that two opaque objects cannot be represented in the same direction. Demonstrations that readers can perform, and that support this argument, are provided on the Perception website at http://www.perceptionweb.com/perc0102/ono.html.     

The Use of Multitrait–Multimethod Data for Detecting Nonlinear Relationships: The Case of Psychological Climate and Job Satisfaction

Previous monomethod research has found mixed support for nonlinear effects between certain job characteristics (e.g., job autonomy, job complexity) and outcome variables (e.g., job performance). We hypothesized that these weak nonlinear findings may be due to the prevalence of monomethod research that can lead to a lack of complete measurement and/or introduce common methods variance, either of which may mask the true shape of relationships. Using hierarchical regression analyses and a multitrait–multimethod (MTMM) research design, we found strikingly different results between monomethod and MTMM data when considering the relationships between three psychological climate variables and job satisfaction. While the monomethod results mirrored earlier inconclusive findings, the MTMM data indicated that nonlinear equations explained significantly more of the relationship between all three climate dimensions and job satisfaction. These results suggest that the use of MTMM data allows one to more effectively test for nonlinear effects. Furthermore, these nonlinear results suggest that the format of employee questionnaires should probably change from asking how much an employee has of certain constructs to asking does the employee want more or less of these constructs.     

Parenting and Family Stress Treatment Outcomes in Attention Deficit Hyperactivity Disorder (ADHD): An Empirical Analysis in the MTA Study

Parenting and family stress treatment outcomes in the MTA study were examined. Male and female (579), 7–9-year-old children with combined type Attention Deficit Hyperactivity Disorder (ADHD), were recruited at six sites around the United States and Canada, and randomly assigned to one of four groups: intensive, multi-faceted behavior therapy program alone (Beh); carefully titrated and monitored medication management strategy alone (MedMgt); a well-integrated combination of the two (Comb); or a community comparison group (CC). Treatment occurred over 14 months, and assessments were taken at baseline, 3, 9, and 14 months. Parenting behavior and family stress were assessed using parent-report and child-report inventories. Results showed that Beh alone, MedMgt alone, and Comb produced significantly greater decreases in a parent-rated measure of negative parenting, Negative/Ineffective Discipline, than did standard community treatment. The three MTA treatments did not differ significantly from each other on this domain. No differences were noted among the four groups on positive parenting or on family stress variables. Results are discussed in terms of the theoretical and empirically documented importance of negative parenting in the symptoms, comorbidities and long-term outcomes of ADHD.     

Secondary prevention interventions for young drug users: a systematic review of the evidence

This paper reviews the international scientific evidence on the effectiveness of secondary prevention interventions for young drug users. The review provides insight into the effectiveness of interventions that have been evaluated using moderately strong research designs. Most of the studies included are from the United States of America. Some interventions are effective in reducing drug use and associated problems while others have no or mixed effect. Those successful in reducing drug use include behavior therapy, Minnesota 12-step programs, residential care, and general drug treatment. Those with either no effect or mixed effect include schools interventions. Involving parents and other agencies may enhance an intervention's effect. There is a lack of good quality studies outside the USA. Future interventions should focus on either low- or high-risk groups of young drug users. Future research should be conducted on a wider range of services for young people and include non-medical outcomes such as communication skills, schooling, employment, family relations, and economic costs.     

Moral conviction: another contributor to attitude strength or something more?

Attitudes held with strong moral conviction (moral mandates) were predicted to have different interpersonal consequences than strong but nonmoral attitudes. After controlling for indices of attitude strength, the authors explored the unique effect of moral conviction on the degree that people preferred greater social (Studies 1 and 2) and physical (Study 3) distance from attitudinally dissimilar others and the effects of moral conviction on group interaction and decision making in attitudinally homogeneous versus heterogeneous groups (Study 4). Results supported the moral mandate hypothesis: Stronger moral conviction led to (a) greater preferred social and physical distance from attitudinally dissimilar others, (b) intolerance of attitudinally dissimilar others in both intimate (e.g., friend) and distant relationships (e.g., owner of a store one frequents), (c) lower levels of good will and cooperativeness in attitudinally heterogeneous groups, and (d) a greater inability to generate procedural solutions to resolve disagreements.     

Socioeconomic status, resources, psychological experiences, and emotional responses: a test of the reserve capacity model

The current study used ecological momentary assessment to test several tenets of the reserve capacity model (L.C. Gallo & K. A. Matthews, 2003). Women (N = 108) with varying socioeconomic status (SES) monitored positive and negative psychosocial experiences and emotions across 2 days. Measures of intrapsychic and social resources were aggregated to represent the reserve capacity available to manage stress. Lower SES was associated with less perceived control and positive affect and more social strain. Control and strain contributed to the association between SES and positive affect. Lower SES elicited greater positive but not negative emotional reactivity to psychosocial experiences. Women with low SES had fewer resources relative to those with higher SES, and resources contributed to the association between SES and daily experiences.     

Constraints and triggers: situational mechanics of gender in negotiation

The authors propose 2 categories of situational moderators of gender in negotiation: situational ambiguity and gender triggers. Reducing the degree of situational ambiguity constrains the influence of gender on negotiation. Gender triggers prompt divergent behavioral responses as a function of gender. Field and lab studies (1 and 2) demonstrated that decreased ambiguity in the economic structure of a negotiation (structural ambiguity) reduces gender effects on negotiation performance. Study 3 showed that representation role (negotiating for self or other) functions as a gender trigger by producing a greater effect on female than male negotiation performance. Study 4 showed that decreased structural ambiguity constrains gender effects of representation role, suggesting that situational ambiguity and gender triggers work in interaction to moderate gender effects on negotiation performance.     

MORPHINE TOLERANCE AS A FUNCTION OF RATIO SCHEDULE: RESPONSE REQUIREMENT OR UNIT PRICE?

Key pecking by 3 pigeons was maintained by a multiple fixed-ratio 10, fixed-ratio 30, fixed-ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1-s access to food. Acute administration of morphine, l-methadone, and cocaine dose-dependently decreased overall response rates in each of the components. When a rate decreasing dose of morphine was administered daily, tolerance, as measured by an increase in the dose that reduced response rates to 50% of control (i.e., the ED50 value), developed in each of the components; however, the degree of tolerance was smallest in the fixed-ratio 90 component (i.e., the ED50 value increased the least). When the l-methadone dose-effect curve was redetermined during the chronic morphine phase, the degree of cross-tolerance conferred to l-methadone was similar across components, suggesting that behavioral variables may not influence the degree of cross-tolerance between opioids. During the chronic phase, the cocaine dose-effect curve shifted to the right for 2 pigeons and to the left for 1 pigeon, which is consistent with predictions based on the lack of pharmacological similarity between morphine and cocaine. When the morphine, l-methadone, and cocaine dose-effect curves were redetermined after chronic morphine administration ended, the morphine and l-methadone ED50s replicated those obtained prior to chronic morphine administration. The morphine data suggest that the fixed-ratio value (i.e., the absolute output) determines the degree of tolerance and not the unit price.