A DEVELOPMENTAL DEFICIT IN LOCALIZING OBJECTS FROM VISION

Abstract— We describe a college student, A. H., with a developmental deficit in determining the location of objects from vision. The deficit is selective in that (a) localization from auditory or tactile information is intact, (b) A H reports the identity of mislocalized objects accurately, (c) visual localization errors preserve certain parameters of the target location, and (d) visual localization is severely impaired under certain stimulus conditions, but nearly intact under other conditions. These results bear on the representation and processing of location information in the visual system, and also have implications for understanding developmental dyslexia.     

Auditory temporal perception deficits in the reading-impaired: A critical review of the evidence

We assess evidence and arguments brought forward by Tallal (e.g., 1980) and by the target paper (Farmer & Klein, 1995) for a general deficit in auditory temporal perception as the source of phonological deficits in impaired readers. We argue that (1) errors in temporal order judgment of both syllables and tones reflect difficulty in identifying similar (and so readily confusable) stimuli rapidly, not in judging their temporal order; (2) difficulty in identifying similar syllables or tones rapidly stem from independent deficits in speech and nonspeech discriminative capacity, not from a general deficit in rate of auditory perception; and (3) the results of dichotic experiments and studies of aphasics purporting to demonstrate left-hemisphere specialization for nonspeech auditory temporal perception are inconclusive. The paper supports its arguments with data from a recent control study. We conclude that, on the available evidence, the phonological deficit of impaired readers cannot be traced to any co-occurring nonspeech deficits so far observed and is phonetic in origin, but that its full nature, origin, and extent remain to be determined.     

Brief report: Effects of informational feedback on aluminum can recycling

The impact of informational feedback on the depositing of aluminum cans in recycling receptacles at a medium-sized university was investigated. Informational signs were placed over 20-recycling receptacles in three academic buildings. Each informational sign was placed at eye level, with the number of aluminum cans deposited for recycling during the previous week displayed in red digits. A 65% increase in the number of aluminum cans deposited in recycling receptacles with the informational signs was observed. Furthermore, removal of the informational signs was observed to reliably decrease the number of aluminum cans deposited. These results are discussed in the context of employing feedback to increase environmental protection behaviors.     

An historical preface to engineering ethics

This article attempts to distinguish between science and technology, on the one hand, and engineering, on the other, offering a brief introduction to engineering values and engineering ethics. The method is (roughly) a philosophical examination of history. Engineering turns out to be a relatively recent enterprise, barely three hundred years old, to have distinctive commitments both technical and moral, and to have changed a good deal both technically and morally during that period. What motivates the paper is the belief that a too-easy equation of engineering with technology tends to obscure the special contribution of engineers to technology and to their own professional standards and so, to obscure as well both the origin and content of engineering ethics.     

Five points and a lament about Range and Cotton's "Reports of assent and permission in research with children: illustrations and suggestions

This comment responds to an article by Range and Cotton (1995) on reporting of parental permission and child assent procedures in published articles for 4 psychology journals. Issue is taken with the assumptions, methodology, interpretations, and implications of listing researchers in the Range and Cotton article. There is no evidence researchers failed in their ethical obligations or that children were put at risk. Reporting permission/assent in publications is not an ethical requirement. Listing researchers as "failing" to do something not part of an ethical code is lamentable. Too many unfortunate implications and problems can be derived from Range and Cotton's analysis and conclusions.     

Reply to William R. Ferrell’s paper “A model for realism of confidence judgments: Implications for underconfidence in sensory discrimination”

Ferrell’s decision-variable partition model and our subjective distance model belong to the same family of Thurstonial models. The subjective distance model is limited to sensory discrimination with the method of constant stimuli and rooted in such notions as discriminal dispersion and sense distance. Ferrell’s model is intended to be wider in scope and to apply to both cognitive and sensory tasks. Both models need supplementary assumptions to predict calibration phenomena. The point of departure for us is the fact that the model predicts under-confidence under “guessing” and the empirical finding that people are about 100% correct when they report “absolutely certain.” Ferrell makes assumptions about cutoffs on the decision variable. The respondent is assumed to adjust or not adjust cutoffs according to “cues to difficulty.” We disagree with Ferrell’s claim that the hard-easy effect is explained by the respondent’s failure to adjust cutoffs sufficiently when there is a change in level of difficulty, and argue that this amounts to little more than a translation of the hard-easy effect into the lingua of Ferrell’s decision-variable partition model. Our argument is that the hard-easy effect is a consequence of the post hoc division of items according to solution probability. In addition, error variance may contribute to regression effects that enlarge the hard-easy effect. Finally, in contrast to Ferrell’s position, we regard inference (cognitive uncertainty) and discrimination (sensory uncertainty) as different psychological processes. An understanding of calibration in these two areas requires separate models.     

Within-category discrimination of musical chords: Perceptual magnet or anchor?

Recent speech research has begun to evaluate the internal structure of categories. In one such study, Kuhl (1991) found that discrimination was poorer for vowel stimuli that were more representative of the category (prototype, or P, set) than it was for less representative stimuli (nonprototype, or NP, set). This finding was interpreted as indicating that a category prototype may function as a “perceptual magnet,” effectively decreasing perceptual distance, and thus discriminability, between stimuli. The present study examines the function of prototypes in a musical category—another natural, but nonspeech category. Paralleling the Kuhl study, representative (P) and less representative (NP) sets of major triad stimuli were constructed, based on equal temperament. Musically experienced subjects rated the stimuli in each set for goodness as a major triad, with the highest rated stimulus serving as a prototype standard for a subsequent discrimination task. Results from the discrimination task demonstrated better performance in the P context than in the NP context. The current nonspeech results indicate that a prototype functions as an anchor rather than a magnet. In addition to providing a natural, nonspeech standard for comparison with speech findings, the results provide some important insights into the nature of musical categories.