Biomedical subjects

Jules Davidoff

Publications and source records attributed to Jules Davidoff.

9 recordsLinked to original sources

PubMed2006

Color terms and color concepts.

In their lead articles, both Kowalski and Zimiles (2006) and O'Hanlon and Roberson (2006) declare a general relation between color term knowledge and the ability to conceptually represent color. Kowalski and Zimiles, in particular, argue for a priority for the conceptual representation in color term acquisition. The complexities of the interaction are taken up in the current commentary, especially with regard to the neuropsychological evidence. Data from aphasic patients also argue for a priority for abstract thought, but nevertheless it may still be that the use of color terms is the only way in which to form color categories even if both linguistic and attentional factors play an important role.

Aptitude↗

PubMed2006

Priming of depth-rotated objects depends on attention and part changes.

Three priming experiments investigated the role of attention and view changes when common objects were rotated in depth. Objects were shown in prime-probe trial pairs. Experiment 1 extended findings by Stankiewicz, Hummel, and Cooper (1998) showing that attended objects primed themselves in the same but not in a reflected view, whereas ignored objects only primed themselves in the same view. In Experiment 2, depth-rotations produced changes in the visible part structure between prime and probe view of an object. Priming after depth-rotation was more reduced for attended objects than for ignored objects. Experiment 3 showed that other depth rotations that did not change the perceived part structure revealed a priming pattern similar to that in Experiment 1, with equivalent reduction in priming for attended and ignored objects. These data indicate that recognition of attended objects is mediated by a part-based (analytic) representation together with a view-based (holistic) representation, whereas ignored images are recognized in a strictly view-dependent fashion.

Attention↗

PubMed2006

Prevalence and correlates of face recognition impairments after acquired brain injury.

Impairments of face recognition after acquired brain injury (ABI) are not restricted to prosopagnosia but commonly arise in association with other cognitive deficits and can be psychosocially debilitating. Despite this, the prevalence and cognitive concomitants of such impairments after ABI have not been systematically investigated. We tested 91 adults with ABI on a range of cognitive measures including several indices of face recognition and learning. The proportion of patients who show impaired performance varied across face learning/recognition tests between 21% and 80%. Principal components analyses indicated orthogonality between impairments of "directed facial processing", associated with memory and visuoperceptual deficits and manifest in slow learning and matching of previously unfamiliar faces, and of "face identification", associated with deficits on verbal tests and manifest in difficulty in naming famous faces. Theoretical and rehabilitative implications are considered.

Adolescent↗

PubMed2006

Cross-species differences in color categorization.

Berlin and Kay (1969) found systematic restrictions in the color terms of the world's languages and were inclined to look to the primate visual system for their origin. Because the visual system does not provide adequate neurophysiological discontinuities to supply natural color category boundaries, and because recent evidence points to a linguistic origin (Davidoff, Davies, & Roberson, 1999), a new approach was used to investigate the controversial issue of the origin of color categories. Baboons and humans were given the same task of matching-to-sample colors that crossed the blue/green boundary. The data and consequent modeling were remarkably clear-cut. All human subjects matched our generalization probe stimuli as if to a sharp boundary close to the midpoint between their training items. Despite good color discrimination, none of the baboons showed any inclination to match to a single boundary but rather responded with two boundaries close to the training stimuli. The data give no support to the claim that color categories are explicitly instantiated in the primate color vision system.

Adult↗

PubMed2004

Color categories: evidence for the cultural relativity hypothesis.

The question of whether language affects our categorization of perceptual continua is of particular interest for the domain of color where constraints on categorization have been proposed both within the visual system and in the visual environment. Recent research (Roberson, Davies, & Davidoff, 2000; Roberson et al., in press) found substantial evidence of cognitive color differences between different language communities, but concerns remained as to how representative might be a tiny, extremely remote community. The present study replicates and extends previous findings using additional paradigms among a larger community in a different visual environment. Adult semi-nomadic tribesmen in Southern Africa carried out similarity judgments, short-term memory and long-term learning tasks. They showed different cognitive organization of color to both English and another language with the five color terms. Moreover, Categorical Perception effects were found to differ even between languages with broadly similar color categories. The results provide further evidence of the tight relationship between language and cognition.

Adolescent↗

PubMed2004

Evidence for holistic representations of ignored images and analytic representations of attended images.

According to the hybrid theory of object recognition (J. E. Hummel, 2001), ignored object images are represented holistically, and attended images are represented both holistically and analytically. This account correctly predicts patterns of visual priming as a function of translation, scale (B. J. Stankiewicz & J. E. Hummel, 2002), and left-right reflection (B. J. Stankiewicz, J. E. Hummel, & E. E. Cooper, 1998). The model also predicts that priming for attended images will generalize over configural distortions (split images), whereas priming for ignored images will not. Three experiments tested and confirmed this prediction. Split images visually primed their intact and split counterparts when they were attended but not when they were ignored, whereas intact images primed themselves whether they were attended or not. The data contribute to the growing body of evidence that 1 function of visual attention is to permit the generation of explicitly relational representations of object shape.

Attention↗

PubMed2004

The development of color categories in two languages: a longitudinal study.

This study unites investigations into the linguistic relativity of color categories with research on children's category acquisition. Naming, comprehension, and memory for colors were tracked in 2 populations over a 3-year period. Children from a seminomadic equatorial African culture, whose language contains 5 color terms, were compared with a group of English children. Despite differences in visual environment, language, and education, they showed similar patterns of term acquisition. Both groups acquired color vocabulary slowly and with great individual variation. Those knowing no color terms made recognition errors based on perceptual distance, and the influence of naming on memory increased with age. An initial perceptually driven color continuum appears to be progressively organized into sets appropriate to each culture and language.

Child, Preschool↗

PubMed2003

A cross-linguistic data bank for oral picture naming in Dutch, English, German, French, Italian, Russian, Spanish, and Swedish (PEDOI).

The well established effect of word frequency on adult's picture naming performance is now called into question. This is particularly true for variables which are correlated with frequency, as is the case of age of word acquisition. Since the work of [Carrol and White, 1973] there is growing agreement among researchers to confer an important role in lexical access to this variable. Indeed, it has been shown ( [Hodgson and Ellis, 1998]) that for normal English-speaking adults only the variables 'age-of-acquisition' and 'name agreement' are independent predictors of naming success among the various variables considered. However, when brain-damaged subjects with and without degenerative pathologies are studied, word frequency and word length as well as concept familiarity all give significant effects ( [Hirsh and Funnell, 1995]; [Lambon Ralph et al., 1998]; [Nickels and Howard, 1995]). Finally, it has been suggested that the production of specific error types may be related to such variables. According to [Nickels and Howard, 1994] the production of semantic errors is specifically affected by 'imageability' and in the recent study by [Kremin et al., 2001] 'age of acquisition' predicts (frank) word finding difficulties.

Adolescent↗

PubMed2002

Development of animal recognition: a difference between Parts and Wholes.

A series of experiments examined children's recognition of animals by their features (Parts) and by the relative scale of the parts (Wholes). They were asked to identify the correct picture of an animal they could name from the original plus two computer-generated alternatives. We examined the developmental trends associated with upright (Studies 1 and 3) and inverted presentations (Study 3). Both experiments confirmed children's superior ability in dealing with the recognition of animal Parts over animal Wholes, especially for the younger ages tested (6- and 10-year-olds). It was not until the ages of 15-16 that children demonstrated equal performance on Whole and Part items. The late acquisition of animal Whole recognition is compared to the late acquired configural skills proposed for face recognition.

Adolescent↗