Biomedical subjects

William G Hayward

Publications and source records attributed to William G Hayward.

6 recordsLinked to original sources

PubMed2006

Font tuning associated with expertise in letter perception.

Font tuning (FT) occurs when observers recognize a sequence of letters presented in the same font faster than in different fonts (Sanocki 1987, 1988 Journal of Experimental Psychology. Human Perception and Performance 13 267-278; 14 472-480). Here, we test the hypothesis that FT is associated with expertise with a specific writing system. We developed a systematic search task allowing the measurement of FT over a large number of letters and generalized the finding of FT from English readers viewing Roman letters to Chinese readers viewing Chinese characters. Non-Chinese readers did not show evidence of FT for Chinese characters in this search task. We also used a simpler 3-letter identification task to directly compare novice and expert readers, and to explore FT for different aspects of font such as fill, slant, and aspect ratio. We found that experts tune to aspect ratio but not to the other font changes. These findings reveal that letters are not processed visually in the same manner as shapes, and suggest an explanation for the cortical specialization obtained in the visual system for letters.

Humans↗

PubMed2006

Expert face coding: configural and component coding of own-race and other-race faces.

Configural and holistic coding are hallmarks of face perception. Although recent studies have shown that own-race faces are coded more holistically than other-race faces, the evidence for better configural coding of own-race faces is equivocal. We directly measured configural and component coding of own- and other-race male faces in Caucasian and Chinese participants. We manipulated individual features (components) or their spatial relations (configurations) using a novel morphing method to vary difficulty parametrically and tested sensitivity to these changes in a sequential matching task. Both configural and component coding were better for upright own-race than for upright other-race faces. Inversion impaired detection of configural changes more than it did detection of component changes, but also impaired performance more for easier discriminations, independent of type of change. These results challenge explanations of face expertise that rely solely on configural and holistic processing, and also call into question the widespread interpretation of large inversion decrements as diagnostic of configural coding.

Adult↗

PubMed2005

Constraints on view combination: effects of self-occlusion and differences among familiar and novel views.

The use of multiple familiar views of objects to facilitate recognition of novel views has been addressed in a number of behavioral studies, but the results have not been conclusive. The present study was a comprehensive examination of view combination for different types of novel views (internal or external to the studied views) and different objects (amoeboid objects and objects composed of geons; objects with and without self-occlusion across rotation). The authors found that the advantage gained from the study of 2 views was more than the generalization from each of the studied views presented alone. This facilitation occurred only for internal views but not external views. In addition, the benefits from the study of 2 views diminished when (a) the studied views did not share the same visible features and when (b) the studied views were separated by a small angular difference.

Humans↗

PubMed2005

When are viewpoint costs greater for silhouettes than for shaded images?

Previous studies of object recognition have shown efficient recognition of silhouettes, suggesting that much of the information used to recognize objects resides in the outline. These studies, however, have used objects that contain many components, which provide redundant information. In this study, we examined recognition of silhouettes of less-complex objects, so that redundant information was reduced. We found that viewpoint generalization costs (the decrement of performance when recognizing nonstudied views) were greater for silhouettes than for shaded images, even when the same qualitative components were visible in the outline of both studied and nonstudied views. Thus, silhouettes do not always allow for view generalization as efficiently as do shaded images.

Form Perception↗

PubMed2003

After the viewpoint debate: where next in object recognition?

A debate on whether object representations capture isolated viewpoints or ranges of views has dominated research in object recognition in recent years, but now seems to be waning. Rather than assume a narrow model in which either structural or view information is used to recognize an object, researchers have begun to examine how these properties might be used cooperatively. A recent paper by Foster and Gilson confirms sensitivity to both types of information, which combine in an additive framework to predict recognition performance.

Journal Article↗

PubMed2002

BOLD activity during mental rotation and viewpoint-dependent object recognition.

We measured brain activity during mental rotation and object recognition with objects rotated around three different axes. Activity in the superior parietal lobe (SPL) increased proportionally to viewpoint disparity during mental rotation, but not during object recognition. In contrast, the fusiform gyrus was preferentially recruited in a viewpoint-dependent manner in recognition as compared to mental rotation. In addition, independent of the effect of viewpoint, object recognition was associated with ventral areas and mental rotation with dorsal areas. These results indicate that the similar behavioral effects of viewpoint obtained in these two tasks are based on different neural substrates. Such findings call into question the hypothesis that mental rotation is used to compensate for changes in viewpoint during object recognition.

Analysis of Variance↗