David R Keeble

• BSc Hons Psychology, BSc Hons Physics, PhD
• Professor (Associate) at University of Nottingham Malaysia

Successful face recognition is important for social interactions and public security. Although some preliminary evidence suggests that anodal and cathodal transcranial direct current stimulation (tDCS) might modulate own- and other-race face identification, respectively, the findings are largely inconsistent. Hence, we examined the effect of both a...

The functional role of the occipital face area (OFA) and the fusiform face area (FFA) in face recognition is inconclusive to date. While some research has shown that the OFA and FFA are involved in early (i.e., featural processing) and late (i.e., holistic processing) stages of face recognition respectively, other research suggests that both region...

Saccadic localisation of targets of various properties has been extensively studied, but rarely for texture-defined figures. In this paper, three experiments that investigate the way information from a texture target is processed in order to provide a signal for eye movement control are presented. Participants made saccades to target regions embedd...

The Cambridge Face Memory Test (CFMT) is one of the most important measures of individual differences in face recognition and for the diagnosis of prosopagnosia. Having two different CFMT versions using a different set of faces seems to improve the reliability of the evaluation. However, at the present time, there is only one Asian version of the t...

Previous cross‐cultural eye‐tracking studies examining face recognition discovered differences in the eye movement strategies that observers employ when perceiving faces. However, it is unclear (1) the degree to which this effect is fundamentally related to culture and (2) to what extent facial physiognomy can account for the differences in looking...

In visual perception, human faces are detected efficiently: we look at them preferentially and it is difficult to ignore them. While such preferential processing has been established for faces, little is known about potentially similar processing of body parts such as hands. Oculomotor and related control mechanisms can be quantified by measuring e...

It is widely accepted that holistic processing is important for face perception. However, it remains unclear whether the other-race effect (ORE) (i.e. superior recognition for own-race faces) arises from reduced holistic processing of other-race faces. To address this issue, we adopted a cross-cultural design where Malaysian Chinese, African, Europ...

RESEARCH BACKGROUND: It is a part of our everyday perception to notice other people’s hand and finger postures. Hand perception is vital for social interaction and cognitive processes. Occasionally, after an injury, distorted finger postures occur, which are very conspicuous and can make an observer feel uncomfortable. This exceptional salience ref...

PURPOSE: Human beings are understood to apply mental simulation when they view images of hands. One approach to studying this process is to present images of hands on a computer screen while participants give left- and right-hand keyboard responses depending on the stimulus features. As this setup involves spatial proximity between stimuli and resp...

The own-race bias (ORB) is a reliable phenomenon across cultural and racial groups where unfamiliar faces from other races are usually remembered more poorly than own-race faces (Meissner and Brigham, 2001). By adopting a yes–no recognition paradigm, we found that ORB was pronounced across race groups (Malaysian–Malay, Malaysian–Chinese, Malaysian–...

The own-race bias (ORB) is a reliable phenomenon across cultural and racial groups where unfamiliar faces from other races are usually remembered more poorly than own-race faces (Meissner and Brigham, 2001). By adopting a yes–no recognition paradigm, we found that ORB was pronounced across race groups (Malaysian–Malay, Malaysian–Chinese, Malaysian–...

The headscarf conceals hair and other external features of a head (such as the ears). It therefore may have implications for the way in which such faces are perceived. Images of faces with hair (H) or alternatively, covered by a headscarf (HS) were used in three experiments. In Experiment 1 participants saw both H and HS faces in a yes/no recogniti...

Hair is a feature of the head that frequently changes in different situations. For this reason much research in the area of face perception has employed stimuli without hair. To investigate the effect of the presence of hair we used faces with and without hair in a recognition task. Participants took part in trials in which the state of the hair ei...

The Muslim headscarf (hijab) conceals the hair and other external facial features, and so may have implications for the ease with which faces are remembered. To investigate this, 24 South Asian females were photographed wearing the headscarf (HS), with their own hair (OH) visible, and with all external features cropped (CR). Participants viewed a n...

Spatial arrangement has been shown to facilitate both detection of a threshold target by collinear flankers and detection of smooth chains within random arrays of suprathreshold elements. Here, we investigate the effect of alignment between texture elements on orientation-based texture segmentation. Textures composed of Gabor elements were used in...

The tilt aftereffect (TAE) has been used previously to probe whether contours defined by different attributes are subserved by the same or by different underlying mechanisms. Here, we compare two types of contours between texture surfaces, one with texture orientation contrast across the edge (orientation contrast contour; OC) and one without, comm...

Search Current issue Forthcoming All volumes Perception homepage ECVP Pion homepage ECVP 2004 Abstractdoi:10.1068/v040353 Cite as: Keeble D R T, Hazel C A, 2004, "how important is punctuation" Perception 33 ECVP Abstract Supplement how important is punctuation D R T Keeble, C A Hazel it seems clear that some punctuation is necessary for quick and c...

We demonstrate that the 1st- and 2nd-order characteristics of a visual stimulus can have a profound influence on each other in terms of perceived position. We use the parameter of spatial separation to selectively manipulate the effect of one characteristic upon the other. 1st-order features have their largest effect upon the perceived position of...

Purpose: Spatial arrangement has been shown to be a critical factor both in detection facilitation of a threshold target by collinear flankers and in detection of smooth chains within random arrays of suprathreshold elements. Here, we investigate the effect of alignment between texture elements on human texture perception. Methods: Texture displays...

We investigated biases in the perception of the length of the circumference of a circle. Subjects observed stimuli comprising a line passing through the centre of a circle. The task was to decide if the line or the circumference of the circle was longer. The line-length was varied by means of a staircase in order to determine the PSE. Brief present...

We used biased random-dot dynamic test stimuli to measure the strength of the motion aftereffect (MAE) to evaluate the usefulness of this technique as a measure of motion adaptation strength. The stimuli consisted of noise dots whose individual directions were random and of signal dots moving in a unique direction. All dots moved at the same speed....

A current, popular, theory of spatial localization holds that the visual system represents the location of simple objects by a single positional tag, the accuracy of which is largely independent of the internal properties of the object. We have already presented evidence of the limitations of such a view (Keeble & Hess (1998). Vision Research, 38,...

Do superimposed textures segregate on the basis of a difference in their luminance spatial frequency? We addressed this question using orientation-gratings, which consist of dense arrays of Gabor micropatterns whose orientations vary sinusoidally across space. Two orientation gratings of the same texture spatial frequency were combined in anti-phas...

We show that the previously reported orientation deficit in amblyopia (Skottun, B. C., Bradley, A., & Freeman, R. D. (1986). Orientation discrimination in amblyopia. Investigative Ophthalmology and Visual Science, 30, 532-537) also occurs for arrays of randomly positioned Gabor micropatterns for which explanations based on either neural disarray or...

We assessed whether the visual system's ability to discriminate subtle perturbations from smoothness in curved shapes was based on 1st-order properties or 2nd-order properties. We investigated which of the two would determine performance in a task where the observer had to detect spatial jitter on aligned, unaligned or unoriented Gabor patches form...

Texture perception is generally found to be scale invariant, that is, the perceived properties of textures do not change with viewing distance. Previously, Kingdom, F. A. A., Keeble, D. R. T., & Moulden, B. (Vision Research, 1995, 35, 79-91) showed that the orientation modulation function (OMF), which describes sensitivity to sinusoidal modulations...

Natural expansions are presented for energetically acceptable configuration-interaction (CI) wavefunctions for the He(2p23P)-like ions when 1<or=Z<or=4. The symmetry of the natural orbitals and their occupation numbers are contrasted with existing results for the 1s2 1S ground state. Moreover, results are given for Coulomb holes, partial holes and...

Energetically acceptable configuration-interaction (CI) wavefunctions for the He(2p2 3P)-like ions are used in their natural expansion form to analyse the separate angular and radial components of electron correlation. Angular Coulomb holes, one- and two-particle radial holes, and several related expectation quantities are calculated for these doub...

The angular and radial components of electron correlation have each been examined in detail for the discrete 2p2 3P states of H-, He, Li+ and Be2+. These doubly excited systems were describe, by highly accurate explicitly correlated wavefunctions. The analysis involved the use of angular Coulomb holes changes in the one- and two-particle radial den...

Momentum properties are examined for the -like systems when . Each doubly excited state (DES) is represented in momentum space by the Dirac - Fourier transform of the Aspromallis configuration-interaction (A-CI) wavefunction. Various truncations of the natural expansions of the transformed A-CI functions are used to investigate characteristics of s...

Doubly-excited states (DES) of simple atoms involve, by comparison with the ground state, relatively slow moving electrons which should therefore be more responsive to electron correlation. Hence, for the 2p2 3P state, correlation effects have been analyzed in detail in terms of Coulomb holes, partial Coulomb holes and (rn12) when 1<or=Z<or=4. Comp...

Several workers have concluded that Gabor alignment tasks are performed by using central tendencies of the micropatterns as a cue. One reason for this conclusion was that the 3-Gabor alignment task is performed equally well whether the orientations of the patches are collinear or orthogonal to the group orientation. We wished to find out if the ori...

A major determinant of human texture segregation and discrimination is the orientational content of the stimuli used. We have investigated the ability of observers to resolve features defined in the orientation domain in a variety of textures. It was found that features had to be separated by at least 13 deg for subjects to discriminate orientation...

Purpose. Many workers believe thai spatial localization in well-separated micropaitern stimuli is achieved by the comparison of locally-extracted positional tags, such as centroids. It had been thought that this was achieved in an orientationindependem way. Last year, however, (Keeble & Hess, ARVO 1996) it was demonstrated that the orientation of t...

It has been found that the 3-Gabor alignment task is performed equally well whether the orientations of the patches are collinear, parallel, or orthogonal. But does the orientation of the individual micropatterns have any effect on performance? The ability (threshold) of subjects to determine whether the middle Gabor patch of a 3-patch display was...

Purpose. Skottun et al. (IOVS, 1986) reported spatial frequency specific orientation discrimination deficits in amblyopia for a relatively large field of grating. Here we assess two possible explanations for this. In the first case, it may result from detectors with broader orientation bandwidths. Alternately, the orientation detectors may have nor...

Two distinct paradigms have characterized most previous studies of texture perception: one has dealt with texture segregation, the other with the processing of texture gradients. Typically, studies of texture segregation have used stimuli with abrupt textural variations, whereas studies of texture gradient processing have used stimuli with smooth t...

The use of raster display devices for the display of graphics causes problems of aliasing when edges or lines are produced. This can be significant in those psychophysical experiments where the orientational properties of the stimulus are important. We have assessed the perceived orientation of a selection of aliased lines by comparing them with th...

Oriented textures were produced with the use of probability density functions modulated sinusoidally over orientation. Orientational contrast sensitivity functions (OCSFs) for a task involving the discrimination of these patterns from orientationally-random textures were found for several human observers. An inverse Fourier transform of this OCSF y...

We have measured the sensitivity of the human visual system to sinusoidal modulations of orientation in micropattern-based textured stimuli. The result is the orientation modulation function, or OMF, which describes this sensitivity as a function of the spatial frequency of orientation modulation. We found that the OMF was bandpass with peak sensit...