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.     

Book reviews

Gott ist schön und Er liebt die Schönheit: God is Beautiful and He Loves Beauty. Alma Giese and J. Christoph Bürgel, 1994. Bern, Peter Lang. 474 pp., hb. n.p., ISBN 3–906750–90–6.

The Concept of Islamic International Criminal Law. Farhad Malekian, 1994. London, Graham & Trotman. 213 pp., £55.00, $92, ISBN 1859660851.

Religion in Europe: contemporary perspectives. S. Gill, G. D'Costa, and U. King (Eds), 1994. Kampen, Kok Pharos. 213 pp., pb., Fl 49.90, ISBN 90–390–0508–7.

Religious Freedom and the Position of Islam in Western Europe. W. A. R. Shadid and P. S. van Koningsveld, 1995. Kampen, Kok Pharos. 229 pp., pb., Fl 64.90, ISBN 90–390–0065–4.

Christianity in the Arab World. HRH Crown Prince El Hassan Bin Talal, 1994. Amman, Arabesque. 120pp., hb.

Holymen of the Blue Nile: the making of an Arab‐Islamic community in the Nilotic Sudan 1500–1850. Neil MHugh. Evanston Illinois, Northwestern University Press. 280pp., hb., $54.95, ISBN 0–8101–1069–5.     

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.     

Grammatical determinants of ambiguous pronoun resolution

Crawley et al. (1990) argue for the primacy of a subject assignment strategy for pronoun assignment during reading, and against the notion of parallel function (Sheldon, 1974). However, most of their items deviated from parallel structure, and none included subject pronouns. In four experiments with subject and nonsubject pronouns, strong parallel function effects emerge when a potential antecedent has the same syntactic role as the pronoun and when the two clauses have the same attachment site and constituent structure. Attachment nonparallelism causes the greatest ambiguity, while the other types lead to more subject assignment overall, although there is always an overlaid parallel function effect. These observations support a model of pronoun assignment according to which potential antecedents are checked for morphological, syntactic and semantic feature matches with the pronoun, and priming/reactivation of syntactic structure across clauses facilitates parallel assignment.This research was supported in part by research grant 410-89-0395 from the Social Sciences and Humanities Research Council of Canada. A preliminary version of the paper was presented at the 1992 meetings of the Canadian Linguistic Association in Charlottetown, Prince Edward Island. I would like to thank Elizabeth Cowper, Keren Rice, Rosemary Stevenson, and an anonymous reviewer for their comments.