PSYCHOPHYSICAL INVARIANTS OF ACHROMATIC COLOUR VISION: II. Albedo/illumination substitution

Lie , I. Psychophysical invariants of achromatic colour vision. II. Albedo/ illumination substitution. Scand. J. Psychol., 1969,10, 176–184.—Can ‘identification of illumination’ be identified as one of the determinants of achromatic vision? Colour constancy is redefined in terms of deviation from albedo/ illumination substitution (A/I-substitution). A series of A/I-substitution experiments, performed under conditions assumed to provide minimal possibilities for identification of illumination, indicate that complete A/I-substitution (zero constancy) is obtained for both brightness and whiteness, provided the test fields are equated with respect to colour temperature and perceived texture.     

PSYCHOPHYSICAL INVARIANTS OF ACHROMATIC COLOUR VISION: III. Colour constancy and its relation to identification of illumination

L ie , I. Psychophysical invariants of achromatic colour vision. III. Colour constancy and its relation to identification of illumination. Scand. J. Psychol ., 1969, 10 , 7.69–281.—Identification of illumination as a separate determinant of the dimensions of achromatic colour was investigated with classical methods for manipulating shifts in perceived level of illumination, while controlling the changes in colour contrast brought about by these methods. With the spot-shadow method, constancy effects may be explained by laws of colour contrast, but not by perceived shifts in illumination, whereas neither explanation holds with the cast-shadow method. Results with a method of conceiled cast-shadow may be consistent with both interpretations.     

PSYCHOPHYSICAL INVARIANTS OF ACHROMATIC COLOUR VISION: IV. Depth adjacency and simultaneous contrast

L ie , I. Psychophysical invariants of achromatic colour vision. IV. Depth adjacency and simultaneous contrast. Scand. J. Psychol ., 1969, 10 , 282–286.— Achromatic colour contrast as a function of adjacent subareas was investigated by a stereoscopic depth technique. The degree of colour contrast was found to be independent of stereoscopic depth.     

PSYCHOPHYSICAL INVARIANTS OF ACHROMATIC COLOUR VISION: I. The multidimensionality of achromatic colour experience

L ie . I. Psychophysical invariants of achromatic colour vision. I. The multi-dimensionality of achromatic colour experience. Scand. J. Psychol ., 1969, 10, 167–175.—The literature relevant to the question of multidimensionality of achromatic colour is briefly reviewed. An experiment confirms that the achromatic scale is bidimensional, and indicates that the dimension of brightness is a direct function of the luminance of the local area inspected, while the dimension of whiteness is a direct function of luminance relations of adjacent areas in the visual field.     

The Ethnic Hierarchy Among Majority and Minority Youth In The Netherlands

This study tests the hypothesis that ethnic groups have consensus about the relative position of ethnic out-groups in society. A survey among ethnic majority and minority youth in the city of Rotterdam indicated that: (a) each ethnic group preferred the in-group, (b) there was consensus on an ethnic hierarchy within ethnic groups, and (c) ethnic groups largely agreed on the ethnic rank order. Among the Dutch respondents, the ethnic hierarchy was found to be related to real cultural differences. The scheme of ethnic preferences corresponded inversely to the rank ordering of the ethnic groups in terms of collectivism. Among ethnic minority youth the rank ordering did not correspond to cultural differences but to existing socioeconomic status differences.     

Inscribing the body, exscribing space

The present paper briefly reviews recent advances in spatial cognition. A central tenet in spatial cognition is that spatial information is simultaneously encoded in multiple formats. It also appears that at the level of neural processing there is no clear distinction between the representation of space and the control of action. I will argue that these findings offer novel insight into the nature of dance and choreography and that the concepts used by cognitive neuroscientists to frame their findings can be fruitfully applied in a choreographic setting. Finally, I will speculate that both dancing oneself and watching dance may enhance one’s experience of space.     

Interactive effects of APOE and CHRNA4 on attention and white matter volume in healthy middle-aged and older adults

In the present study, we investigated age-related changes in interactions between efficiency of neuronal repair mechanisms and efficiency of cholinergic neurotransmission in the context of attentional orienting. In addition, we explored white matter volume changes as possible neuronal underpinnings. A sample of 230 healthy middle-aged (53–64 years) and older (65–75 years) adults was genotyped for polymorphisms of APOE and CHRNA4, a nicotinic receptor subunit gene. Participants were administered a visuospatial attention task involving letter discrimination with location cues of varying validity. Genotype effects on white matter volume were also investigated in a subset of participants who received MRI scans. APOE interacted with CHRNA4, such that APOE-ε4 carriers who were also CHRNA4 TT homozygotes showed disproportionately slowed reaction time (RT) following invalid location cues. The interaction was stronger in the middle-aged participants than in the older participants. There was also a trend for individuals with combined APOE-ε4/CHRNA4 TT genotypes to show both lower white matter volume and slower overall RT on the attention task. The interaction of a neurotransmission gene (CHRNA4) and a susceptibility gene (APOE) suggests that the efficiency of neuronal repair mechanisms may modulate the cholinergic system to influence attentional function.     

Size does matter: Women mentally rotate large objects faster than men

Performance in a computerized “mental rotation” task was measured in groups of males and females while they rotated Shepard‐Metzler‐like cube assemblies on either a standard laptop screen (size = 36 cm) or on a large display wall (584 cm) where the stimuli appeared at considerably larger sizes and within a much wider field of view than that typically used in most spatial tasks. Males and females did not differ significantly in performance in the standard size condition with regards to response time but females performed faster than males in the large display condition. Males were also found to be significantly more accurate than females, regardless of display. We found no sign of trading accuracy for speed for either of the sexes or screen size conditions. We surmise that such an effect may be due to differences in task‐solving strategies between the sexes, where a holistic strategy – which may be preferred by males is negatively affected by large object sizes, whereas a piecemeal approach, that may be preferred by females, is virtually unaffected by display size.