In a recent study, Ludwig and Gilchrist (2002) showed that stimulus-driven oculomotor capture by abrupt onset distractors was modulated by distractor-target similarity: Participants were more likely to fixate an irrelevant onset when it shared the target color. Here we test whether this pattern of performance is the result of (1) inhibition of all items in the distractor color, (2) a response b...

Color and black and white line stimulation produce qualitatively and quantitatively different 2-deoxy[14C]glucose column patterns in the striate cortex of macaque monkeys. Microdensitometry of these stimulus-dependent columns reveals interlaminar density differences that serve as a signature for the stimulus conditions which produced them. Such columns are individually distinct and form a three...

A new type of visual display for presentation of a visual stimulus with high quality was assessed. The characteristics of an organic light-emitting diode (OLED) display (Sony PVM-2541, 24.5 in.; Sony Corporation, Tokyo, Japan) were measured in detail from the viewpoint of its applicability to visual psychophysics. We found the new display to be superior to other display types in terms of spatia...

Observers often fail to detect the appearance of an unexpected visual object ("inattentional blindness"). Experiment 1 studied the effects of fixation position and spatial attention on inattentional blindness. Eye movements were measured. We found strong inattentional blindness to the unexpected stimulus even when it was fixated and appeared in one of the expected positions. The results suggest...

The "watercolor effect" is the wash of illusory color that fills in between two enclosing bichromatic contours. We studied the microgenesis of this illusion by varying the duration of the eliciting stimulus (a yellow/purple contour outlining the Mediterranean Sea) and by varying the duration of a blank interval from stimulus offset to an after-coming mask (the ISI). The illusory wash was rated ...

Categorical perception (CP) occurs when discrimination of items that cross category boundaries is faster or more accurate than discrimination of exemplars from the same category. Categorical perception of color is observed when, for example, a green stimulus and a blue stimulus are more easily distinguished than two stimuli from the same color category (e.g., two different shades of green). Col...

Color matches have been used for a variety of purposes, yet the psychometric properties of color-matching data have not been thoroughly investigated. A method is given for generating psychometric functions for the two ends of the color-matching range by use of a perceptual dimension for stimulus magnitude based on ratios of cone quantal catches. The analysis was applied to Rayleigh match data g...

Neural activity in area V4 was examined to assess (1) whether the effects of attentive selection for stimulus features could be based on the memory of the feature, (2) whether dynamically changing the feature selection would cause activity associated with the newly selected stimuli to pop out, and (3) whether intrusion of more than one stimulus into the receptive field would disrupt the feature...

In this chapter, we discuss our research that reveals how attentional mechanisms can modulate activity of posterior brain regions responsible for processing the unattended attribute of a stimulus. To do so, we utilized fMRI to reveal patterns of regional brain activity for variants of the Stroop task that differ in the nature of the task-irrelevant stimulus attribute. In all variants, individua...