(Mis)estimation of the modal number of desired sexual partners.

Misperceptions of the social world can lead to actions and social policy that are detrimental to an individual's or group's well-being. Here we investigate whether misperceptions arise when participants make predictions of the modal number of ideal future sexual partners reported by heterosexual cohorts (younger cohort: 18-23 years; older cohort: 24-29 years). For both men and women and in both cohorts, the modal number of reported partners equaled 1.

Using a variant of the optomotor response as a visual defect detection assay in zebrafish.

We describe a visual stimulus that can be used with both larval and adult zebrafish (Danio rerio). This protocol is a modification of a standard visual behavior analysis, the optomotor response (OMR). The OMR is often used to determine the spatial response or to detect directional visuomotor deficiencies.

Helix rotation: luminance contrast controls the shift from two-dimensional to three-dimensional perception.

We present the helix rotation phenomenon, an array of moving dots that creates a conflict between two potential perceptions: a 3D Pulfrich-like horizontal rotation and a low-spatial-frequency up-down motion. We show that observers perceive up-down motion when the dots are equiluminant with the background and when the display is blurred; that the addition of sparse luminance information to equiluminant and blurred displays produces 3D perception; and that the balance between the perception of 3D rotation and up-down motion depends on the magnitude of the luminance contrast. The results are discussed in terms of the luminance capture of equiluminant information.

The Perpetual Diamond: Contrast Reversals Along Thin Edges Create the Appearance of Motion in Objects.

The Perpetual Diamond produces motion continuously and unambiguously in one direction despite never physically changing location. The phenomenon consists of a steady, mid-luminance diamond bordered by four thin edge strips and a surrounding background field. The direction of motion is determined by the relative phases of the luminance modulation between the edge strips and the background.

Remote controls illusion: strange interactions across space cannot be explained by simple contrast filters.

The visual system has separable visual encoding for luminance and for contrast modulation [J. Vis.8(1), B152 (2008)1534-736210.

Spatial filtering, color constancy, and the color-changing dress.

The color-changing dress is a 2015 Internet phenomenon in which the colors in a picture of a dress are reported as blue-black by some observers and white-gold by others. The standard explanation is that observers make different inferences about the lighting (is the dress in shadow or bright yellow light?); based on these inferences, observers make a best guess about the reflectance of the dress. The assumption underlying this explanation is that reflectance is the key to color constancy because reflectance alone remains invariant under changes in lighting conditions.

The Star Wars Scroll Illusion.

The Star Wars Scroll Illusion is a dynamic version of the Leaning Tower Illusion. When two copies of a Star-Wars-like scrolling text are placed side by side (with separate vanishing points), the two scrolls appear to head in different directions even though they are physically parallel in the picture plane. Variations of the illusion are shown with one vanishing point, as well as from an inverted perspective where the scrolls appear to originate in the distance.

Feature- and Face-Exchange illusions: new insights and applications for the study of the binding problem.

i.e., how are humans able to maintain a relatively stable representation of objects and features even though the visual system processes many aspects of the world separately and in parallel? We previously investigated this issue with a variant of the bounce-pass paradigm, which consists of two rectangular bars moving in opposite directions; if the bars are identical and never overlap, the motion could equally be interpreted as bouncing or passing.

Paradoxical effect of spatially homogenous transparent fields on simultaneous contrast illusions.

In simultaneous brightness contrast (SBC) demonstrations, identical mid-luminance disks appear different from each other when one is placed on a black background while the other is placed on a white background. The strength of SBC effects can be enhanced by placing a semi-transparent layer on top of the display (Meyer's effect). Here, we try to separate the causes of Meyer's effect by placing a spatially homogenous transparent layer over a standard SBC display, and systematically varying the transmission level (alpha=0, clear; alpha=1, opaque) and color (black, gray, white) of the semi-transparent layer.

Contrast-contrast asynchronies.

We introduce the "contrast-contrast asynchrony," a dynamic stimulus configuration that combines elements of the Shapiro contrast asynchrony with elements of the Chubb contrast-contrast illusion. In the contrast-contrast asynchrony, static textured fields surround two textured fields; one surround has high-contrast texture, and the other has low-contrast texture. The contrasts of the center fields modulate in phase with each other at 1 Hz, and as a consequence, the difference between the contrast of the centers and the contrast of the respective surround modulates in antiphase.

The separation of monocular and binocular contrast.

The contrast asynchrony is a stimulus configuration that illustrates the visual system's separable responses to luminance and luminance contrast information (Shapiro, 2008; Shapiro et al., 2004). When two disks, whose luminances modulate in phase with each other, are each surrounded by a disk, one light and one dark, observers can see both the in-phase brightness signals and the antiphase contrast signals and can separate the two.

The maintenance and disambiguation of object representations depend upon feature contrast within and between objects.

The brain processes many aspects of the visual world separately and in parallel, yet we perceive a unified world populated by objects. In order to create such a "bound" percept, the visual system must construct object-centered representations out of separate features and then maintain the representations across changes in space and time. Here, we examine the role of features themselves in maintaining and disambiguating the representations of the objects to which they belong.

A first- and second-order motion energy analysis of peripheral motion illusions leads to further evidence of "feature blur" in peripheral vision.

Background: Anatomical and physiological differences between the central and peripheral visual systems are well documented. Recent findings have suggested that vision in the periphery is not just a scaled version of foveal vision, but rather is relatively poor at representing spatial and temporal phase and other visual features. Shapiro, Lu, Huang, Knight, and Ennis (2010) have recently examined a motion stimulus (the "curveball illusion") in which the shift from foveal to peripheral viewing results in a dramatic spatial/temporal discontinuity.

Edges can eliminate the appearance of the contrast asynchrony.

Recent work in the Shapiro laboratory has suggested that the visual response to changes in chromaticity/luminance can be separated from the visual response to changes in spatial contrast. Here, we examine how spatial edges affect the relative perceptual weighting of these two types of responses. In the experiments, we separate color from color contrast with a 'contrast asynchrony' stimulus in which the luminance of two identical rectangles varies sinusoidally over time.

Spillmann's weaves are more resilient than Hermann's grid.

In a classic Hermann grid display, faint and transient (illusory) spots are produced at the intersections of a white grid superimposed on a black background (or vice versa). In a variant of the Hermann grid developed by Spillmann and Levine (Spillmann, L., & Levine, J.

Separating color from color contrast.

Visual objects can be described by their color and by their color contrast. For example, a red disk in front of a white background appears "red with high color contrast," whereas a red disk in front of a slightly less-saturated red background will appear "red with low color contrast." This paper examines the visual response to color contrast in a cone-based color space.

Last but not least.

A central tenet of Gestalt psychology is that the visual scene can be separated into figure and ground. The two illusions we present demonstrate that Gestalt processes can group spatial contrast information that cuts across the figure/ground separation. This finding suggests that visual processes that organise the visual scene do not necessarily require structural segmentation as their primary input.

Visual illusions based on single-field contrast asynchronies.

A single-field contrast asynchrony refers to a stimulus configuration in which there is a single temporally modulated field and multiple sources of contrast information; the sources of contrast information modulate at different temporal phases or at different temporal frequencies. In this paper we show how single-field contrast asynchronies can lead to a wide variety of visual illusions. We investigate, in depth, the window shade/rocking disk configuration, in which a temporally modulated disk is surrounded by a split annulus (i.

Induced contrast asynchronies may be useful for luminance photometry.

Shapiro et al. (2004) introduced a new visual effect (the induced contrast asynchrony) that demonstrates a perceptual separation between the response to a modulated light and the response to contrast of the light relative to background. The effect is composed of two physically identical disks, one surrounded by a dark annulus and the other by a light annulus.

Induced contrast asynchronies.

We document a new type of perceptual effect in which asynchronous contrast signals are presented simultaneously with synchronous luminance signals. The template for the basic effect consists of two physically identical disks (.75-deg diameter, 40 cd/m2), one surrounded by a dark annulus (1.

Time-course of S-cone system adaptation to simple and complex fields.

We examine the temporal nature of adaptation at different stages of the S-cone color system. All lights were restricted to the S-cone-only (a constant L and M) cardinal axis in color space passing through mid-white (W). The observer initially adapted to a steady uniform field with a chromaticity on the -S end of the axis or on the +S end of the axis or a complex field composed of chromaticy -S and +S (+/-S adaptation).

Cone-specific mediation of rod sensitivity in trichromatic observers.

Purpose: The slope of the rod threshold versus the illuminance (TVI) function changes with the wavelength of the background light. This study was conducted to determine whether the changes in slope are due to the stimulation of specific cone classes.

Methods: An eight-channel optical system was used to generate lights that differed in cone and rod photoreceptor illuminance.