PIGEONS ARE SENSITIVE TO THE SPATIAL ORGANIZATION OF COMPLEX VISUAL STIMULI

Abstract— Two experiments investigated the role of spatial organisation in the discrimination and generalization of complex visual stimuli by pigeons. In Experiment 1, after pigeons had been trained to discriminate line drawings of four objects, they were tested with novel pictures in which the same component parts of the objects were spatially rearranged. The spatially scrambled pictures led to a dramatic drop in recognition accuracy, hut responding remained above chance. In Experiment 2, pigeons reached a high level of discriminative performance when required to choose among four different spatial arrangements of the same object parts. These results confirm Cerella's (1980) conclusion that pigeons discriminate the component parts of complex visual stimuli, but. unless it is assumed that the scrambling deleted or created emergent features, the results disconfirm his conclusion that spatial organization plays no role in pigeons' picture perception.     

Person-centered theory and the contemporary practice of psychological testing

This paper examines the effects of person-centered theory on contemporary psychological testing. Seven basic ideas or assumptions, which are integral to and guide the testing process, are identified and briefly discussed. Each idea is considered to have been affected either directly or indirectly by person-centered philosophy. Some of the ways in which these ideas are reflected in contemporary testing practice are indicated.     

Arguing about definitions

What are the implications of taking seriously Chaïm Perelman's proposition that “definitions are rhetorical”? Efforts to find Real Definitions are dysfunctional to the extent they direct argumentation toward pseudo “is” claims and away from explicit “ought” claims about how words are to be used. Addressing definitional disputes explicitly as propositions ofought rather thanis could put on the agenda the pragmatic concerns of definitional choice that might otherwise remain tacit.     

Twenty-five basic theorems in situation and world theory

Conclusion The foregoing set of theorems forms an effective foundation for the theory of situations and worlds. All twenty-five theorems seem to be basic, reasonable principles that structure the domains of properties, relations, states of affairs, situations, and worlds in true and philosophically interesting ways. They resolve 15 of the 19 choice points defined in Barwise (1989) (see Notes 22, 27, 31, 32, 35, 36, 39, 43, and 45). Moreover, important axioms and principles stipulated by situation theorists are derived (see Notes 33, 37, and 38). This is convincing evidence that the foregoing constitutes a theory of situations. Note that worlds are just a special kind of situation, and that the basic theorems of world theory, which were derived in previous work, can still be derived in this situation-theoretic setting. So there seems to be no fundamental incompatibility between situations and worlds — they may peacably coexist in the foundations of metaphysics. The theory may therefore reconcile two research programs that appeared to be heading off in different directions. And we must remind the reader that the general metaphysical principles underlying our theory were not designed with the application to situation theory in mind. This suggests that the general theory and the underlying distinction have explanatory power, for they seem to relate and systematize apparently unrelated phenomena.This research was conducted at the Center for the Study of Language and Information (CSLI). I would like to thank John Perry for generously supporting my research both at CSLI and in the Philosophy Department at Stanford. I would also like to thank Bernard Linsky, Chris Menzel, Harry Deutsch and Tony Anderson for many worthwhile and interesting suggestions for improving the paper. An earlier version of the paper, more narrowly focused on situation theory, has appeared in Zalta (1991).     

Continuous and discrete latent structure models for item response data

Relations are examined between latent trait and latent class models for item response data. Conditions are given for the two-latent class and two-parameter normal ogive models to agree, and relations between their item parameters are presented. Generalizationss are then made to continuous models with more than one latent trait and discrete models with more than two latent classes, and methods are presented for relating latent class models to factor models for dichotomized variables. Results are illustrated using data from the Law School Admission Test, previously analyzed by several authors.     

The conceptual structure of sex role stereotypes in college students

This study investigated sex stereotypes as natural language categories. Ten years ago, sex stereotypes were found to have a core-peripheral structure similar to that of the nonevaluative categories studies by Rosch (1973). Changes and stability in these conceptions were studied by having 56 female and 56 male undergraduate students rate 217 adjectives on Likert scales according to how well each adjective represented their own view of typical Men or Women. Mean ratings were analyzed to reveal a structure of core, peripheral, and nonmembers for Men and for Women. As was the case ten years ago, core traits reflected dimensions of “niceness-nurturance” for Women and “potency-strength” for Men. Female students also viewed Women as “competent,” while male students also viewed Women as “socially effective.” Adjectives that constituted the core for one category were generally placed in the periphery for the other category. As compared to ten years ago, the peripheries of the categories were expanded and showed a greater degree of overlap. College students' conceptions of Men and Women are best characterized as overlapping rather than as bipolar opposites. The formation of sex stereotype categories was discussed in terms of cognitive and social learning processes.     

The Future of Psychology in Family Medicine

Psychology has been integral to the field of family medicine since its inception as a medical specialty in the 1960s. Psychologists and other behavioral scientists contribute to family medicine in teaching clinical skills, in defining research questions, in developing research methodology, and in creating integrated physical/mental health care delivery systems. Future developments in the field of psychology in family medicine are likely to emphasize development and evaluation of screening measures which identify mental health problems in primary care, development of early intervention for those mental health problems, and more precise measurement of process and quality of care and health outcomes. Psychologists have an important role to fulfill in educating physicians on alternatives to pharmacologic and medical interventions for common presenting problems in primary care. However, current economic forces shaping the practice of medicine may work against further enhancing the efficacy of the physician in dealing with psychosocial issues. The future role of psychology in family medicine is not yet delineated, and while the move toward parity of reimbursement for mental and physical health care delivery may enhance this collaboration, there is a need to continue to evaluate how the psychological well-being of patients is influenced in the evolution of new models of care delivery.     

Managing Conflict in Dutch Organizations: A Test of the Relevance of Deutsch's Cooperation Theory1

Deutsch's theory of cooperative and competitive conflict may be usefully extended to Dutch people. Results of LISREL analyses on data collected from interviews of Dutch employees in 2 companies indicate that competitive goals interfered with the open, constructive discussion of opposing views. However, cooperative goals were not found to contribute to constructive controversy. Dutch who discussed their opposing views openly made progress on the task, worked efficiently, and strengthened their work relationship and their confidence in future collaboration. These results do not argue that Dutch and North Americans handle conflict similarly, for how these groups operationalize the theory may differ significantly. Goal interdependence may have the potential to be a framework for promoting conflict management between Dutch and North Americans.