Towards a general theory of representation

Summary The models of science are representations of a part of reality. Every science has its own specific rules of constructing models, but there are many common rules that must be followed. These rules are to be part of what may be called a general theory of representation. This paper discusses some general aspects of representation that must be considered before such a general theory can be created. There are five sections: (1) an introduction to the topic of representation in general; (2) an overview of some general types of representation, such as goal-directed and self-organizational representations; (3) a short discussion of representation in some specific disciplines; (4) some formal aspects of representations; and (5) a discussion of epistemological aspects of representation, especially scientific reduction and mental causation.This paper was written during participation in the Research Project Mind and Brain, at the Centre for Interdisciplinary Research, University of Bielefeld, BRD.     

Visual perception and the guidance of locomotion without vision to previously seen targets

Two experiments were performed to assess the accuracy and precision with which adults perceive absolute egocentric distances to visible targets and coordinate their actions with them when walking without vision. In experiment 1 subjects stood in a large open field and attempted to judge the midpoint of self-to-target distances of between 4 and 24 m. In experiment 2 both highly practiced and unpracticed subjects stood in the same open field, viewed the same targets, and attempted to walk to them without vision or other environmental feedback under three conditions designed to assess the effects on accuracy of time-based memory decay and of walking at an unusually rapid pace. In experiment 1 the visual judgments were quite accurate and showed no systematic constant error. The small variable errors were linearly related to target distance. In experiment 2 the briskly paced walks were accurate, showing no systematic constant error, and the small, variable errors were a linear function of target distance and averaged about 8% of the target distance. Unlike Thomson's (1983) findings, there was not an abrupt increase in variable error at around 9 m, and no significant time-based effects were observed. The results demonstrate the accuracy of people's visual perception of absolute egocentric distances out to 24 m under open field conditions. The accuracy of people's walking without vision to previously seen targets shows that efferent and proprioceptive information about locomotion is closely calibrated to visually perceived distance. Sensitivity to the correlation of optical flow with efferent/proprioceptive information while walking with vision may provide the basis for this calibration when walking without vision.     

'It's who you know, not what you know!': Penetrating the credentialling ideology

The kinds of messages teachers give students regarding the value of credentials in the job-getting package during a period of high youth unemployment are explored. The response made by students to the credentialling ideology promoted in schools, and their construction of the job-getting formula, are also described. The validity of the two versions of job-getting strategies is considered in the light of evidence provided by a number of empirical research projects. The superiority of student knowledge in this area is used to present a case for a critical and democratic education which appropriates and legitimises the student voice.     

Having it all? Combining work and family in a male and a female profession

Are women in a female-dominated profession more successfully able to combine work and family obligations than women in a male-dominated profession? To explore this question, a comparison was made between the family status and careers of 747 women librarians (a female-dominated profession) and those of 449 women MBAs (a male-dominated profession). It was expected that the librarians would marry earlier and have more children. This general prediction was not supported. Over half of both groups of women were married, and after controlling for age, there were no differences in number of children. However, many women without children in both groups reported that they would like to be mothers. This disparity between wanting children and not having them was more common for women MBAs than women MLSs. MBAs and librarians were about equally likely to have had job interruptions, but librarians were more likely to have worked part-time. Reasons for an interruption to full-time work were as likely to be for problems finding (full-time) work as for family responsibilities. Librarians' salaries were much lower, but job interruptions and part-time work had a more negative effect on the salaries of women in business. In sum, the data suggest that many of the women surveyed have not combined motherhood with a professional career and that it is probably somewhat more difficult to combine a family with a career in business than with a career in library science.     

Overt responding in computer-based training

This experiment compared the extent to which students learned facts included in computer-based-training frames that required an overt response to those that did not. Frames included two types of facts: Some facts had one word missing which had to be supplied by the student (active facts). Other facts had no missing words and required no overt response (passive facts). Each student completed four 14-fact modules in random order. Two of the modules contained frames with all active facts. Each frame in the other two modules contained one active and six passive facts. Paper pretests and posttests showed that students learned twice as many facts when all facts in the module were active than when only one in seven were active. The modules that included passive facts required one-fifth the time to complete than those with only active facts. Students learned more facts per minute of training in one of the two modules that included passive facts than in the two modules with only active facts.     

The Future of Psychology in Medicaid's Health Delivery System for People with Disabilities

State Medicaid programs are rapidly converting fee-for-service health delivery systems to managed care for people with disabilities. In theory, managed care models of health delivery will substantially improve the quality of care for people with disabilities, but in reality, few successful models exist. This period of transition holds both opportunities and challenges for psychologists in medical settings. Because Medicaid reforms for people with disabilities may herald similar reforms for both the public and the private sectors, psychology's response will determine its role in the future of health care delivery for this population. Changes in training and increased attention to outcomes research, innovations in practice, and advocacy will be the keys to success.     

The Future of Psychology in Departments of Psychiatry

Health care reform has put increasing pressure on faculty of medical schools to become self-supporting. Opportunities for clinical revenue will decrease, but psychologists who are able to generate research funding will become increasingly competitive, albeit as mercenaries, i.e., capable of paying their own way plus generating a profit to support departmental operations and educational programs. Changes in the health care system signal an end to psychiatry's paternalistic relationship to psychology and present opportunities for psychology proactively to influence its future role in health care. Research, political action, and revised scientific mission, models, and roles represent important strategies in the redefining of psychology as a basic science and major profession in health care.     

2-Deoxy-d-Galactose Effects on Passive Avoidance Memorization in the Rat

2-Deoxy-d-galactose (do-gal) hinders glycoprotein fucosylation. This compound was intracerebroventricularly administered to male adult Wistar rats in order to assess whether it could exert amnesic effects on a passive avoidance response (PAR) to be learned in the light–dark box apparatus. Three experiments were performed. In the first, do-gal was administered immediately after the acquisition trials at three dosages (2, 4, and 8 μmol). It was found that only the 4-μmol dosage was followed by PAR disruption. In the second, do-gal was administered at the adequate dosage (4 μmol) either 30 min before the acquisition trial or 30 min before retrieval testing. It was found that only the preretrieval administration was followed by PAR impairment. In the third, do-gal (4 μmol) was administered in postacquisition, at increasing postacquisition delays (0.25, 1.5, 4, and 6 h). It was found that there was PAR disruption only after do-gal administration at the shortest (0.25 h) delay. The results confirm that in the rat, glycoprotein fucosylation is involved in some of the phases of memory trace processing, and they are discussed in relation to other findings in the rat and the chick.