Pupil dilations reflect why rembrandt biased female portraits leftward and males rightward.

Portrait painters are experts at examining faces and since emotional content may be expressed differently on each side of the face, consider that Rembrandt biased his male portraits to show their right-cheek more often and female portraits to show their left-cheek more often. This raises questions regarding the emotional significance of such biased positions. I presented rightward and leftward facing male and female portraits.

Attention to endogenous and exogenous cues affects auditory localization.

Three experiments examine attentional differences in auditory localization using either endogenous or exogenous visual cues. Participants were presented with visual cues on a computer screen and asked to localize auditory targets presented through headphones. In conditions in which the auditory and visual stimuli traveled in the same direction, participants showed illusory directional hearing (Hari in Neurosci Lett 189:29-30, 1995) in that the targets were perceived to travel through the head.

We infer light in space.

In studies of lightness and color constancy, the terms lightness and brightness refer to the qualia corresponding to perceived surface reflectance and perceived luminance, respectively. However, what has rarely been considered is the fact that the volume of space containing surfaces appears neither empty, void, nor black, but filled with light. Helmholtz (1866/1962) came closest to describing this phenomenon when discussing inferred illumination, but previous theoretical treatments have fallen short by restricting their considerations to the surfaces of objects.

Timing: A missing key ingredient in typical fMRI studies of emotion.

Lindquist et al. provide a compelling summary of the brain bases of the onset of emotion. Their conclusions, however, are constrained by typical fMRI techniques that do not assess a key ingredient in emotional experience - timing.

Magno and parvo stimuli affect illusory directional hearing in normal and dyslexic readers.

In an experimental paradigm adapted from Hari (1995), forty observers listened via headphones to 8 binaural clicks: 4 left-ear leading followed by 4 right-ear leading with either 38 or 140 ms interstimulus intervals (ISIs). Concurrently, they viewed either foveal or peripheral visual stimuli designed to activate either the parvocellular or magnocellular pathway. They then reported the perceived location of each click-pair.

Emotive hemispheric differences measured in real-life portraits using pupil diameter and subjective aesthetic preferences.

The biased positioning of faces exposed to viewers of Western portraiture has suggested there may be fundamental differences in the lateralized expression and perception of emotion. The present study investigates whether there are differences in the perception of the left and right sides of the face in real-life photographs of individuals. The study paired conscious aesthetic ratings of pleasantness with measurements of pupil size, which are thought to be a reliable unconscious measure of interest first tested by Hess.

Visual signals bias auditory targets in azimuth and depth.

In the psychophysical phenomenon visual bias, an accurately localized irrelevant signal, such as a light, impairs localization of a spatially discrepant target, such as a sound, when the two stimuli are perceived as unified. Many studies have demonstrated visual bias in azimuth, but none have tested directly or found this effect in depth. The current study was able to produce over 90% bias in azimuth and somewhat less (83%) bias in depth.

Grouping by Regularity and the perception of illumination.

The purpose of this work is to describe how the visual system groups surfaces of unequal lightness under complex patterns of illumination. We propose that the Gestalt principle of Grouping by Regularity explains this process better than the more often cited principle of Grouping by Similarity. In our first experiment we demonstrate that in a perceptual organization task, pitting proximity against illumination gradients, discounting the illuminant was contingent upon the periodicity of the illuminant.

Hemispheric laterality measured in Rembrandt's portraits using pupil diameter and aesthetic verbal judgements.

Eckhard Hess claimed that pupils dilate to pleasant images and constrict to unpleasant images. However, his work was confounded since his image's luminances and contrasts across conditions were inconsistent. We overcome this limitation and suggest a new, promising methodology for research in this area.

Visual biasing of auditory localization in azimuth and depth.

Correctly integrating sensory information across different modalities is a vital task, yet there are illusions which cause the incorrect localization of multisensory stimuli. A common example of these phenomena is the "ventriloquism effect". In this illusion, the localization of auditory signals is biased by the presence of visual stimuli.

Cross-modal detection using various temporal and spatial configurations.

To better understand temporal and spatial cross-modal interactions, two signal detection experiments were conducted in which an auditory target was sometimes accompanied by an irrelevant flash of light. In the first, a psychometric function for detecting a unisensory auditory target in varying signal-to-noise ratios (SNRs) was derived. Then auditory target detection was measured while an irrelevant light was presented with light/sound stimulus onset asynchronies (SOAs) between 0 and ±700 ms.

Light location influences the perceived locations of internal sounds.

Numerous studies have shown that visual stimuli can bias the perceived location of auditory stimuli. Here, we sought to determine if a visual stimulus can also bias the perceived location of multiple internal auditory stimuli. Fifty subjects were presented with a train of eight binaural click-pairs over headphones while a single flash of light was presented either to the left or to the right side of a central fixation point on an otherwise black CRT screen.

Mondrian, eye movements, and the oblique effect.

Observers prefer Mondrian's paintings in their original orientation compared to when rotated--"the oblique effect" (Latto et al, 2000 Perception 29 981-987). We tested whether eye movements could provide any insight into this aesthetic bias. While recording fixation duration and saccade length, we presented eight Mondrian paintings dated 1921-1944 on a CRT in either their original or seven rotated positions to ten observers who used a Likert scale to report how (dis)pleasing they found each image.

The anatomical locus of T-junction processing.

Inhomogeneous surrounds can produce either asymmetrical or symmetrical increment/decrement induction by orienting T-junctions to selectively group a test patch with surrounding regions [Melfi, T., & Schirillo, J. (2000).

Gender's effect on the hemispheric laterality of Rembrandt's portraits.

In 64% of Rembrandt's female portraits the poser's left-cheek faces the viewer. However, this occurs in only 33% of his male portraits. This asymmetry is consistent with viewers rating Rembrandt's left-cheeked male portraits as likely to be avoided, which may reflect that aggressive displays of dominance are governed by the contralateral right-hemisphere, while rating left-cheeked female faces as likely to be approached may indicate sexual attractiveness.

The greater ability of graphical versus numerical displays to increase risk avoidance involves a common mechanism.

By displaying a risk reduction of 50% graphically rather than numerically, Stone, Yates, and Parker significantly increased professed risk-avoidant behavior. The current experiments replicated this effect at various risk ratios. Specifically, participants were willing to spend more money to reduce a risk when the risk information was displayed by asterisks rather than by numbers for risk-reduction ratios ranging from 3% to 97%.

Lights can reverse illusory directional hearing.

Adding brief flashes of light to a train of auditory clicks [R. Hari, Illusory directional hearing in humans, Neurosci. Lett.

Chromatic shadow compatibility and cone-excitation ratios.

Logvinenko [Perception 31, 201 (2002)] asserts that Adelson's wall-of-blocks illusion [Science 262, 2042 (1993)], where identical gray-cube surface tops appear to differ in brightness, arises when the surfaces surrounding the cube tops are shadow compatible, creating a concomitant illusion of transparency. We replicated Logvinenko's main findings in the chromatic domain across three experiments in which observers match cube tops in hue, saturation, and brightness. A second set of stimuli adjusted cone-excitation ratios across the apparent transparency border [Proc.

Three-dimensional spatial grouping affects estimates of the illuminant.

The brightnesses (i.e., perceived luminance) of surfaces within a three-dimensional scene are contingent on both the luminances and the spatial arrangement of the surfaces.

Articulation: brightness, apparent illumination, and contrast ratios.

Luminance edges in the environment can be due to regions that differ in reflectance or in illumination. In three experiments, we varied the spatial organization of 10 achromatic (simulated) surfaces so that some arrangements were consistent with an ecologically valid and parsimonious interpretation of 5 surfaces under two different illuminants. A constant contrast-ratio along a luminance edge in the scene allows this interpretation.