Colour appearance is affected not only by perceptual but also by linguistic context

Terminology is a crucial problem in science, since quite often the terms used to denote theoretical concepts are directly taken from the vocabulary of common words, which usually have multiple meanings. To solve this problem, scientists must operationalize the theoretical concepts they use but, in psychology, sometimes, this can be a difficult task, since the meaning of the terms used to give the instructions to observers can interfere with the spontaneous meaning that observers give to those terms. Starting from some empirical observations, we show that colour appearance is affected not only by the perceptual but also by the linguistic context

Photometric, geometric and perceptual factors in illumination-independent lightness constancy

It has been shown that lightness constancy depends on the articulation of the visual field (Agostini & Galmonte, 1999). However, among researchers there is little agreement about the meaning of “articulation.” Beyond the terminological heterogeneity, an important issue remains: What factors are relevant for the stability of surface color perception? Using stimuli with two fields of illumination, we explore this issue in three experiments. In Experiment 1, we manipulated the number of luminances, the number of reflectances, and the number of surfaces and their spatial relationships; in Experiment 2, we manipulated the luminance range; finally, in Experiment 3 we varied the number of surfaces crossed by the illumination edge. We found that there are two relevant factors in optimizing lightness constancy: (1) the lowest luminance in shadow and (2) the co-presence of patches of equal reflectance in both fields of illumination. The latter effect is larger if these patches strongly belong to each other. We interpret these findings within the albedo hypothesis

Lightness constancy: ratio invariance and luminance profile

The term simultaneous lightness constancy describes the capacity of the visual system to perceive equal reflecting surfaces as having the same lightness despite lying in different illumination fields. In some cases, however, a lightness constancy failure occurs; that is, equal reflecting surfaces appear different in lightness when differently illuminated. An open question is whether the luminance profile of the illumination edges affects simultaneous lightness constancy even when the ratio invariance property of the illumination edges is preserved. To explore this issue, we ran two experiments by using bipartite illumination displays. Both the luminance profile of an illumination edge and the luminance ratio amplitude between the illumination fields were manipulated. Results revealed that the simultaneous lightness constancy increases when the luminance profile of the illumination edge is gradual (rather than sharp) and homogeneous (rather than inhomogeneous), whereas it decreases when the luminance ratio between the illumination fields is enlarged. The results are interpreted according to the layer decomposition schema, stating that the visual system splits the luminance into perceived lightness and apparent illumination components. We suggest that illumination edges having gradual and homogeneous luminance profiles facilitate the luminance decomposition process, whereas wide luminance ratios impede it

Auditory Modeling in Sport: Theoretical Framework and Practical Applications

Visual models, i.e. live demonstrations or film clips, are widely used in sport as training instruments. Nevertheless, in recent years some research demonstrated that the well known property of sounds to effectively represent the temporal structure of a given task and to promote its accurate reproduction, is not valid only for simple motor gestures, but also for the complex movements that characterize sport performances. As a consequence, there is a growing interest towards the study and the implementation of auditory models as an alternative to the visual ones traditionally used. The present work begin by theoretically frameworking the use of auditory modeling in sport according to the Theory of Event Coding. Then, some of the practical applications of the two auditory modeling techniques, i.e. Movement Sonification and Second Order Biofeedback, are synthetically reviewed

The perceptual contrast of impossible shadow edges

Luminance ratios along shadow edges remain the same even when they cross reflectance borders. According to Gilchrist (1988, Perception & Psychophysics 43 415 ^ 424) this so-called ratio-invariance property is a crucial factor in the perception of shadows. However, Soranzo and Agostini (2004, Perception 33 1359 ^ 1368) suggested that in some conditions (named `impossible shadows'), a luminance pattern might still be perceived as a shadow even if the ratio-invariance property along its edge is violated. This can occur when an edge is collinear with another edge (contextual edge) which incorporates it, shares the same polarity, and generates a larger ratio. The hypothesis that impossible shadows are actually perceived as shadows is here tested by comparing the perceptual contrast of a luminance edge in the absence of a contextual edge (control condition) to that of both possible shadow edges (where the contextual and mediating edge share the same ratio) and impossible shadow edges (where the ratio of the contextual edge is larger rather than that at the mediating edge). We found that the perceived contrast of luminance edges shrinks in both possible and impossible shadow conditions rather than in the control condition. This evidence supports the hypothesis that a luminance pattern might be perceived as a shadow even when the ratio-invariance property is violated

Autonomous Physical Exploration Influences Spatial Representation: Evidence From Blind and Sighted.

Evidences demonstrated that verbal information allows to construct a mental representation of space, even for persons who have no previous experience of sight. However, the construction of a mental model from verbal description is not presentation-free, as the verbal description anchors participants to a single perspective. The aim of our study is to test the perspective of spatial representation after the physical exploration of space, in order to avoid the influence of format presentation. We asked visual impaired and sighted participants to explore autonomously a room and then to perform a Sentence Verification Task, with sentences presented in an egocentric and in an allocentric version. We measured both response time and accuracy. Data demonstrated a better performance with allocentric perspective, even if the response time suggests that participants are more confident with the egocentric perspective. In conclusion, we suggest that the physical exploration of space leads to the development of an allocentric representation