Are there nontrivial constraints on colour categorization?

In this target article the following hypotheses are discussed: (1) Colour is autonomous: a perceptuolinguistic and behavioural universal. (2) It is completely described by three independent attributes: hue, brightness, and saturation: (3) Phenomenologically and psychophysically there are four unique hues: red, green, blue, and yellow; (4) The unique hues are underpinned by two opponent psychophysical and/or neuronal channels: red/green, blue/yellow. The relevant literature is reviewed. We conclude: (i) Psychophysics and neurophysiology fail to set nontrivial constraints on colour categorization. (ii) Linguistic evidence provides no grounds for the universality of basic colour categories. (iii) Neither the opponent hues red/green, blue/yellow nor hue, brightness, and saturation are intrinsic to a universal concept of colour. (iv) Colour is not autonomous.     

Multiple information sources in interceptive timing

This study was designed to explore the limitations of tau (τ) as an explanatory construct for the timing of interceptive action. This was achieved by examining the effects of environmental structure and binocular vision on the timing of the grasp in a simple one-handed catch. In two experiments, subjects were required to catch luminous balls of different diameters (4, 6, 8 and 10 cm) in a completely darkened room. In the first experiment the influence of the presence vs. absence of an environmental background structure (both under monocular viewing) was tested, and in the second experiment the influence of monocular vs. binocular vision was examined. It was found that irrespective of the presence of environmental structure, an effect of ball size occurred in the monocular viewing conditions. That is, in monocular viewing conditions the grasp was initiated and completed earlier for the larger balls as compared to the smaller ones, while in the binocular viewing condition subjects behaved in accordance with a constant time to contact strategy: no effects of ball size were found. It is concluded that under binocular viewing a binocular information source is used, while in the monocular viewing condition a lower order information source like image size or image velocity is probably involved.     

The Development of a Clinical Rating Scale the McMaster Model of Family Functioning

This article describes the development and validation of the McMaster Clinical Rating Scale (MCRS). The MCRS is a 7-item scale designed to be completed by a trained rater after completion of an in-depth interview of the family. We present data from four new studies and review previously published articles concerning the reliability, validity, and clinical utility of the MCRS. Adequate interrater reliability and rater stability were obtained. The MCRS was found to correlate significantly with the self-report Family Assessment Device and to discriminate between families in different phases of a depressive disorder.     

ON ULTIMATE EPISTEMIC FOUNDATIONS1

This paper is a contribution to the debate on epistemic foundationalism. Section I expounds and criticises Hans Albert's critical rationalist antifoundationalism position. Section I1 discusses Karl-Otto Apel's ‘transcendental pragmatic’ argument for ultimate epistemic foundations. Section III suggests how the latter argument can be restated so as to avoid ambiguity and yield a plausible case for epistemic foundationalism.     

Revisiting university student gender role perceptions

Gender role perceptions of five objects—Ideal Woman, Ideal Man, Most Women, Most Men and Self—were elicited from 3300 university students, 81% of whom were Caucasian, with 7% Hispanic, 6% African-American, and 4% Asian. Profiles of student responses for the five objects provided a comprehensive updating of 1970s research on student gender roles. Women (N= 1842) and men (N= 1148) students generally preferred an androgynous Ideal Woman. Women also preferred an androgynous Ideal Man, but men preferred a masculine sex-typed Ideal Man. Women and men's perceptions of Most Women and Men continued to be sex-typed. Men's self perceptions were androgynous, while women saw themselves as feminine sex-typed. Findings suggest that little change in students' gender role perceptions has occurred in the past 15 years.     

Marital attributions in spouses of depressed patients

Causal attributions (i.e., locus, stability, globality) and responsibility attributions (i.e., bad intent, selfish motivation, blame) were assessed in the spouses of 27 depressed psychiatric inpatients and 30 nondepressed dyads to test predictions derived from Hooley's (1987) symptom-controllability model of marital distress. Results indicated that (1) depressed patients and their spouses were less dyadically adjusted than nondepressed spouses, (2) causal and responsibility attributions about depressive behaviors predicted lower dyadic adjustment, and (3) attributions of causality mediated the relationship between group status (depressed or nondepressed) and dyadic adjustment among spouses who had higher expectations for their partner to change. Results suggest that among spouses with a high expectancy for change, depression may be a risk factor for marital distress.     

Extraction of relief from visual motion

We quantified the ability of human subjects to discriminate the relative distance of two points from a slanted plane when viewing the projected velocities of this scene (orthographic projection). The relative distance from a plane (called relief) is a 3-D property that is invariant under linear (affine) transformations. As such, relief canin principle be extracted from the instantaneous projected velocity field; a metric representation, which requires the extraction of visual acceleration, is not required. The stimulus consisted of a slanted planeP (specified by three points) and two pointsQ ₁ andQ ₂ that are non-coplanar withP. This configuration of points oscillated rigidly around the vertical axis. We have measured thesystematic error andaccuracy with which human subjects estimate the relative distance of pointsQ ₁ andQ ₂ from planeP as a function of the slant of_P. The systematic error varies with slant: it is low for small slant values, reaches a maximum for medium slant values, and drops again for high slant values. The accuracy covaries with the systematic error and is thus high for small and large slant values and low for medium slant values. These results are successfully modeled by a simple relief-from-motion computation based on local estimates of projected velocities. The data are well predicted by assuming (1) a measurement error in velocity estimation that varies proportionally to velocity (Weber’s law) and (2) an eccentricity-dependent underestimation of velocity.     

Effects of surface texture on weight perception when lifting objects with a precision grip

In this paper, we show that, when lifting an object using a precision grip with the distal pads of the thumb and index finger at its sides, the perceived weight depends on the object’s surface texture. The smoother the surface texture, the greater the perceived weight. We suggest that a smoother object is judged to be heavier because the grip force, normal to the surface, required to prevent it from slipping is greater. The possibility of there being an influence of surface texture per se is excluded by a second experiment that employed a variant of the precision grip in which the thumb supports the weight of the object from underneath. With the grip oriented in this way, there is no need to match grip force to surface texture and, under these conditions, there is no effect of surface texture on weight perception. In the first two experiments, the test and comparison weights were lifted successively by the same hand. In a third experiment, the effect of surface texture was replicated for sequential lifts made with separate hands. Thus, the effect is not restricted to comparisons made with the same hand.