Properties of spatial representations: Data from sighted and blind subjects

Five questions concerning the properties of spatial representations are explored. (1) How accurately does a spatial representation correspond to the true scene? (2) If inaccurate, how does it differ? (3) Are representations of a familiar scene more accurate than those of an unfamiliar one? (4) Do representations of a scene currently in view differ from those retained in memory? (5) Do the representations of the blind have properties comparable to those-of the sighted? Seven sighted and 7 highly mobile blind subjects, all familiar with a room, and 6 sighted subjects unfamiliar with it, were asked to estimate the absolute distances between 10 salient objects in the room. The 14 familiar subjects made their estimates twice: while they were in the room, and while they were remote from it. Regression analyses showed that the estimates of all subjects had strong metric properties, being linearly related to true distance, with a true zero point; and multidimensional scaling showed that all subjects produced distance estimates that could be scaled in two dimensions to closely match the actual locations of the objects. Familiarity had no effect. The effect of location of testing was the same for both the sighted and the blind: all subjects displayed better spatial knowledge when tested in the room; and all subjects underestimated true distance substantially when tested out of the room. The results showed no qualitative differences as a function of blindness, at least for these highly skilled blind travelers.     

Infant use of relative motion as information for form: Evidence for spatiotemporal integration of complex motion displays

Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age.     

Anticipated outgroup evaluations and intergroup bias

A study is reported that tests the hypothesis that group members exhibit intergroup bias in response to the belief that outsiders will discriminate against them. To this end, two experimental conditions are included in which subjects anticipate either biased evaluations or fair evaluations respectively. In a control condition, subjects do not expect to be evaluated from an external source. Results indicated, as expected, that those who anticipated biased evaluations from an outgroup exhibited bias themselves, while those who anticipated fair evaluations exhibited outgroup favouritism. The fact that control subjects exhibited the same degree of bias as those who anticipated biased evaluations from the outgroup poses some difficulties for the hypothesized connection between anticipated discrimination and intergoup bias. Thus, it appears that intergroup bias is the rule and not the exception in an intergroup context. Nevertheless, it is clear that anticipated evaluations of outgroup members can effect intergroup bias.     

Inferential procedures for multifaceted coefficients of generalizability

A two-facet measurement model with broad application in the behavioral sciences is identified, and its coefficient of generalizability (CG) is examined. A normalizing transformation is proposed, and an asymptotic variance expression is derived. Three other multifaceted measurement models and CGs are identified, and variance expressions are presented. Next, an empirical investigation of the procedures follows, and it is shown that, in most cases, Type I error control in inferential applications is precise, and that the estimates are relatively efficient compared with the correlation coefficient. Implications for further research and for practice are noted. In an Appendix, four additional models, CGs, and variance expressions are presented.The research reported herein formed part of a doctoral dissertation conducted by Marsha Schroeder (Schroeder, 1986), under the direction of Ralph Hakstian, at the University of British Columbia. We acknowledge with thanks the contributions to this research of Todd Rogers and James Steiger. We are also very indebted to an mous reviewer who provided some important clarifications in connection with two of the models considered. Some support for this research was provided by a grant to Ralph Hakstian from the Natural Sciences and Engineering Research Council of Canada.     

Modeling item responses when different subjects employ different solution strategies

A model is presented for item responses when different subjects employ different strategies, but only responses, not choice of strategy, can be observed. Using substantive theory to differentiate the likelihoods of response vectors under a fixed set of strategies, we model response probabilities in terms of item parameters for each strategy, proportions of subjects employing each strategy, and distributions of subject proficiency within strategies. The probabilities that an individual subject employed the various strategies can then be obtained, along with a conditional estimate of proficiency under each. A conceptual example discusses response strategies for spatial rotation tasks, and a numerican example resolves a population of subjects into subpopulations of valid responders and random guessers.The first author's work was supported by Contract No. N00014-85-K-0683, project designation NR 150-539, from the Cognitive Science Program, Cognitive and Neural Sciences Division, Office of Naval Research. We are grateful to Murray Aitkin, Isaac Bejar, Neil Dorans, Frederiksen, and Marklyn Wingersky for their comments and suggestions, and to Alison Gooding, Maxine Kingston, Donna Lembeck, Joling Liang, and Kentaro Yamamoto for their assistance with Example 2.     

The electronic teaching theater: Interactive hypermedia and mental models of the classroom

The introduction of hypermedia into the classroom presents both an opportunity to expand the power of teaching through electronic facilitation of the media and a challenge to redesign the classroom and instructional environment to exploit the enhanced features of hypermedia. This paper briefly surveys the current state of computers in the classroom and then argues that a more integrated approach is required. To this end, the concept of an electronic teaching theater is proposed which takes advantage of hypermedia and collaborative work environments. The aim of the electronic teaching theater is not to totally redesign the classroom and instructional interaction, but rather to facilitate it using well understood metaphors to lay out the dynamics of classroom interaction on the electronic media and to use the results from research in human/computer interaction to design the interface. To facilitate the application of hypermedia, a model of instructional interaction among the students, the instructors, the course material, and the products of instruction is presented. A number of component models pertaining to course preparation, lectures, note taking, and other instructional activities are then discussed that should prove useful in designing the electronic classroom. The origin of these models is the mental representation of the interaction as perceived by the teacher and the student. The idea is to start with such models as a base metaphor, to instantiate the metaphors in the electronic classroom, and then to explore innovations in the technology that go beyond the strict application of the metaphor. This work was supported in part by a grant from AT&T to the University of Maryland during the author’s visit to the Medical Research Council—Applied Psychological Unit, Cambridge, England. Appreciation is expressed to Patricia Wright and Richard M. Young for their helpful comments on this paper.     

Values of Postpartum Women from the Inner City: An Exploratory Study

An exploratory study of the values of inner-city postpartum women was conducted. Subjects were largely single, with many on/or going on public assistance. Each subject was given the Rokeach Value Scale and asked to prioritize the terminal values (goals) in terms of herself and the instrumental values (means) in terms of what she would like to teach her child. Rankings were compared to corresponding rankings compiled by a national sample, considered a more traditional era, and by marital status within the postpartum mother sample itself. Economic values were ranked higher by inner-city mothers than by the national sample. The top terminal value was family security and the top instrumental value was responsible. When compared by marital status, the only significant difference was the higher ranking of mature love given by married women. Results suggests that the values of the inner-city single postpartum mother can be conceptualized as a mosaic incorporating values shared with the mainstream and values adapted to the conditions of poverty.     

Neural Network Models and Mechanisms of Strategy Development

The focus of this paper is mechanisms that may be responsible for intellectual and developmental differences in the cognitive strategies of typical and atypical children, including those with mental retardation. The discussion of these mechanisms is based on behavioral experiments on external memory strategies and on a set of neural network models designed for these tasks. Following the review of the external memory research, the rationale for using neural network models, how they have been used in other research, and their specific application to intellectual and developmental differences in external memory, including the results of several simulations, are reviewed. This is followed by a discussion of the mechanisms of intellectual differences and developmental change included in the models and some challenges for this type of modeling. Neural network modeling is discussed as an asset to research on cognitive development.     

Whatever Happened to Culturalism: From Horney to Lacan

The American Journal of Psychoanalysis -