On the flexibility of strategies for center estimation.

When subjects are asked to indicate the center of a spatially distributed stimulus, the features that control their responses tend to vary (1) across subjects and (2) as stimulus properties are altered. Here we ask: can subjects bring these different response tendencies under top-down control? In each of three tasks, all using briefly displayed, Gaussian dot-clouds, subjects were trained to perform different center-estimation responses. In the "mass task," the target was the centroid of the dots.

Inadequate pitch-difference sensitivity prevents half of all listeners from discriminating major vs minor tone sequences.

Substantial evidence suggests that sensitivity to the difference between the major vs minor musical scales may be bimodally distributed. Much of this evidence comes from experiments using the "3-task." On each trial in the 3-task, the listener hears a rapid, random sequence of tones containing equal numbers of notes of either a G major or G minor triad and strives (with feedback) to judge which type of "tone-scramble" it was.

Color scrambles reveal red and green half-wave linear mechanisms plus a mechanism selective for low chromatic contrast.

This paper introduces a new method to determine how subjects make discriminations among red-green texture stimuli. More specifically, the method determines (1) the number of mechanisms in human vision sensitive to lights that vary along the constant-S cardinal axis (cSCA) of DKL space and (2) the sensitivity of each mechanism to cSCA lights. Each of five subjects was tested in four, separately-blocked tasks.

The density effect in centroid estimation is blind to contrast polarity.

Human vision is highly efficient in estimating the centroids of spatially scattered items. However, the processes underlying this remarkable skill remain poorly understood. A salient fact is that in estimating the centroids of dot-clouds, observers underweight densely packed dots relative to isolated dots; thus, when an observer estimates the centroid of a dot cloud, the weight exerted on the subject's response by a given dot tends to be suppressed by other dots near it.

How rests and cyclic sequences influence performance in tone-scramble tasks.

When classifying major versus minor tone-scrambles (random sequences of pure tones), most listeners (70%) perform at chance while the remaining listeners perform nearly perfectly. The current study investigated whether inserting rests and cyclic sequences into the stimuli could heighten sensitivity in such tasks. In separate blocks, listeners classified tone-scramble variants as major versus minor ("3" task) or fourth versus tritone ("4" task).

Sensitivity to major versus minor musical modes is bimodally distributed in young infants.

The difference between major and minor scales plays a central role in Western music. However, recent research using random tone sequences ("tone-scrambles") has revealed a dramatically bimodal distribution in sensitivity to this difference: 30% of listeners are near perfect in classifying major versus minor tone-scrambles; the other 70% perform near chance. Here, whether or not infants show this same pattern is investigated.

A model of the uncertainty effects in choice reaction time that includes a major contribution from effector selection.

Hick's law describes the relation between choice reaction time (RT) and the number of stimulus-response alternatives (NA). For over half a century, this uncertainty effect has been ascribed primarily to the time taken to map a stimulus to its associated response. Here, data from 2 experiments suggests that selection of the appropriate effector-the particular body part to make a response-also contributes substantially to the uncertainty effect.

Variation in target and distractor heterogeneity impacts performance in the centroid task.

In a selective centroid task, the participant views a brief cloud of items of different types-some of which are targets, the others distractors-and strives to mouse-click the centroid of the target items, ignoring the distractors. Advantages of the centroid task are that multiple target types can appear in the same display and that influence functions, which estimate the weight of each stimulus type in the cloud on the perceived centroid for each participant, can be obtained easily and efficiently. Here we document the strong, negative impact on performance that results when the participant is instructed to attend to target dots that consist of two or more levels of a single feature dimension, even when those levels differ categorically from those of the distractor dots.

Avoiding Irreversibility: Engineering Resonant Conversions of Quantum Resources.

We identify and explore the intriguing property of resource resonance arising within resource theories of entanglement, coherence, and thermodynamics. While the theories considered are reversible asymptotically, the same is generally not true in realistic scenarios where the available resources are bounded. The finite-size effects responsible for this irreversibility could potentially prohibit small quantum information processors or thermal machines from achieving their full potential.

The features that control discrimination of an isodipole texture pair.

Visual features such as edges and corners are carried by high-order statistics. Previous analysis of discrimination of isodipole textures, which isolate specific high-order statistics, demonstrates visual sensitivity to these statistics but stops short of analyzing the underlying computations. Here we use a new texture centroid paradigm to probe these computations.

How can observers use perceived size? Centroid versus mean-size judgments.

statistical representations are aggregate properties of the environment that are presumed to be perceived automatically and preattentively. We investigated two tasks presumed to involve these representations: judgments of the centroid of a set of spatially arrayed items and judgments of the mean size of the items in the array. The question we ask is: When similar information is required for both tasks, do observers use it with equal postfilter efficiency (Sun, Chubb, Wright, & Sperling, 2016)? We find that, according to instructions, observers can either efficiently utilize item size in making centroid judgments or ignore it almost completely.

High-capacity preconscious processing in concurrent groupings of colored dots.

Grouping is a perceptual process in which a subset of stimulus components (a group) is selected for a subsequent-typically implicit-perceptual computation. Grouping is a critical precursor to segmenting objects from the background and ultimately to object recognition. Here, we study grouping by color.

Many listeners cannot discriminate major vs minor tone-scrambles regardless of presentation rate.

A tone-scramble is a random sequence of pure tones. Previous studies have found that most listeners (≈ 70%) perform near chance in classifying rapid tone-scrambles composed of multiple copies of notes in G-major vs G-minor triads; the remaining listeners perform nearly perfectly [Chubb, Dickson, Dean, Fagan, Mann, Wright, Guan, Silva, Gregersen, and Kowalski (2013). J.

Dark scene elements strongly influence cuttlefish camouflage responses in visually cluttered environments.

This study investigated how cuttlefish (Sepia officinalis) camouflage patterns are influenced by the proportions of different gray-scales present in visually cluttered environments. All experimental substrates comprised spatially random arrays of texture elements (texels) of five gray-scales: Black, Dark gray, Gray, Light gray, and White. The substrates in Experiment 1 were densely packed arrays of square texels that varied over 4 sizes in different conditions.

Scale-sensitivity: A cognitive resource basic to music perception.

A tone-scramble is a rapid, randomly ordered sequence of pure tones. Chubb, Dickson, Dean, Fagan, Mann, Wright, Guan, Silva, Gregersen, and Kowalski [(2013). J.

Textures as Probes of Visual Processing.

Visual textures are a class of stimuli with properties that make them well suited for addressing general questions about visual function at the levels of behavior and neural mechanism. They have structure across multiple spatial scales, they put the focus on the inferential nature of visual processing, and they help bridge the gap between stimuli that are analytically convenient and the complex, naturalistic stimuli that have the greatest biological relevance. Key questions that are well suited for analysis via visual textures include the nature and structure of perceptual spaces, modulation of early visual processing by task, and the transformation of sensory stimuli into patterns of population activity that are relevant to perception.

Human attention filters for single colors.

The visual images in the eyes contain much more information than the brain can process. An important selection mechanism is feature-based attention (FBA). FBA is best described by attention filters that specify precisely the extent to which items containing attended features are selectively processed and the extent to which items that do not contain the attended features are attenuated.

The centroid paradigm: Quantifying feature-based attention in terms of attention filters.

This paper elaborates a recent conceptualization of feature-based attention in terms of attention filters (Drew et al., Journal of Vision, 10(10:20), 1-16, 2010) into a general purpose centroid-estimation paradigm for studying feature-based attention. An attention filter is a brain process, initiated by a participant in the context of a task requiring feature-based attention, which operates broadly across space to modulate the relative effectiveness with which different features in the retinal input influence performance.

Evidence against global attention filters selective for absolute bar-orientation in human vision.

The finding that an item of type A pops out from an array of distractors of type B typically is taken to support the inference that human vision contains a neural mechanism that is activated by items of type A but not by items of type B. Such a mechanism might be expected to yield a neural image in which items of type A produce high activation and items of type B low (or zero) activation. Access to such a neural image might further be expected to enable accurate estimation of the centroid of an ensemble of items of type A intermixed with to-be-ignored items of type B.

Two mechanisms that determine the Barber-Pole Illusion.

Unlabelled: In the Barber-Pole Illusion (BPI), a diagonally moving grating is perceived as moving vertically because of the narrow, vertical, rectangular shape of the aperture window through which it is viewed. This strong shape-motion interaction persists through a wide range of parametric variations in the shape of the window, the spatial and temporal frequencies of the moving grating, the contrast of the moving grating, complex variations in the composition of the grating and window shape, and the duration of viewing. It is widely believed that end-stop-feature (third-order) motion computations determine the BPI, and that Fourier motion-energy (first-order) computations determine failures of the BPI.

A review of visual perception mechanisms that regulate rapid adaptive camouflage in cuttlefish.

We review recent research on the visual mechanisms of rapid adaptive camouflage in cuttlefish. These neurophysiologically complex marine invertebrates can camouflage themselves against almost any background, yet their ability to quickly (0.5-2 s) alter their body patterns on different visual backgrounds poses a vexing challenge: how to pick the correct body pattern amongst their repertoire.

The 3-dimensional, 4-channel model of human visual sensitivity to grayscale scrambles.

Previous research supports the claim that human vision has three dimensions of sensitivity to grayscale scrambles (textures composed of randomly scrambled mixtures of different grayscales). However, the preattentive mechanisms (called here "field-capture channels") that confer this sensitivity remain obscure. The current experiments sought to characterize the specific field-capture channels that confer this sensitivity using a task in which the participant is required to detect the location of a small patch of one type of grayscale scramble in an extended background of another type.

A moving-barber-pole illusion.

In the barber-pole illusion (BPI), a diagonally moving grating is perceived as moving vertically because of the shape of the vertically oriented window through which it is viewed-a strong shape-motion interaction. We introduce a novel stimulus-the moving barber pole-in which a diagonal, drifting sinusoidal carrier is windowed by a raised, vertical, drifting sinusoidal modulator that moves independently of the carrier. In foveal vision, the moving-barber-pole stimulus can be perceived as several active barber poles drifting horizontally but also as other complex dynamic patterns.

Bimodal distribution of performance in discriminating major/minor modes.

This study investigated the abilities of listeners to classify various sorts of musical stimuli as major vs minor. All stimuli combined four pure tones: low and high tonics (G5 and G6), dominant (D), and either a major third (B) or a minor third (B[symbol: see text]). Especially interesting results were obtained using tone-scrambles, randomly ordered sequences of pure tones presented at ≈15 per second.