Alessandra Galmonte

Perceptual Organization Overcomes the Effects of Local Surround in Determining Simultaneous Lightness Contrast

Lightness induction can occur on the basis of the immediate surround of a region (local interactions) and also on the basis of global factors of perceptual organization. The experiments reported in this article used novel displays that made it possible to differentiate the contributions of these two kinds of factors. The experiments demonstrated, for the first time, that when higher-level factors act contemporaneously with lower-level factors, the contrast effect induced by the global-organization principle of perceptual belongingness overcomes the effect due to retinal lateral inhibition.

A new effect of luminance gradient on achromatic simultaneous contrast.

A new effect in the domain of achromatic simultaneous contrast has been observed. A middle gray region placed at the center of an area filled by a linear achromatic gradient from black (outer part) to white (inner part) is perceived as being much darker than an identical middle gray region surrounded by a reversed gradient. By using a matching task in two experiments, it has been shown that this phenomenon is much stronger than the classical achromatic simultaneous contrast effect. The new effect is interpreted in terms of thealbedo hypothesis.

The Relevance of Auditory Information in Optimizing Hammer Throwers Performance

We experimentally studied the role of the auditory information, and its potential implications to enhance the performance in hammer throwing. We stimulated our athletes auditory by using the rhythmic sound (produced by the impact between the hammer and the air) associated to the best personal throw. The results are coherent with literature claiming that auditory information is an essential factor to guide motor action in sport activities. In fact, all the tested athletes both metrically improved and standardized their performance. This kind of suggestions, merging from applied studies in sport activities, offers important indications to develop cognitive models about mental strategies in sport.

Ecological sounds affect breath duration more than artificial sounds.

Previous research has demonstrated that auditory rhythms affect both movement and physiological functions. We hypothesized that the ecological sounds of human breathing can affect breathing more than artificial sounds of breathing, varying in tones for inspiration and expiration. To address this question, we monitored the breath duration of participants exposed to three conditions: (a) ecological sounds of breathing, (b) artificial sounds of breathing having equal temporal features as the ecological sounds, (c) no sounds (control). We found that participants’ breath duration variability was reduced in the ecological sound condition, more than in the artificial sound condition. We suggest that ecological sounds captured the timing of breathing better than artificial sounds, guiding as a consequence participants’ breathing. We interpreted our results according to the Theory of Event Coding, providing further support to its validity, and suggesting its possible extension in the domain of physiological functions which are both consciously and unconsciously controlled.

The contribution of early auditory and visual information to the discrimination of shot power in ball sports

Objective It is well‐established that early visual information has an important role in human ability to play ball sports, as its correct interpretation promotes accurate predictions concerning the ball motion. Other research highlights that auditory information provides relevant cues in various sport situations. The present study combines these two lines of research with the aim to investigate the contribution of early auditory and visual information to the discrimination of shot power in sport‐specific situations. Design Two experiments were run, one concerning soccer penalty kicks and the other concerning volleyball smashes. In both experiments there were three conditions: Audio, Audiovideo, and Video; a within subjects design was used, with the three conditions carried out in three different days and in a counterbalanced order among participants. Method Participants’ task was to discriminate the power of two penalties/smashes presented in rapid sequence, on the basis of a two‐alternative forced choice paradigm. Results The results revealed that, for both penalties and smashes, response accuracy was above chance level in all the three conditions; moreover, while for the penalties no difference among the conditions was observed, for the smashes participants were more accurate in the Audio and Audiovideo conditions compared to the Video condition. As concerns the response times, for both penalties and smashes participants were faster in the Audio and Audiovideo conditions compared to the Video condition. Conclusions Taken together, the results suggest that the discrimination of shot power was more easily performed on the basis of early auditory information than on the basis of the respective visual information. HighlightsEarly auditory information alone is sufficient to discriminate shot power above chance.Early visual information alone is sufficient to discriminate shot power above chance.For smashes, discrimination is more accurate in presence of early auditory information.Early auditory information promotes faster discriminations of shot power.

Spatial articulation affects lightness.

In a recent paper, Agostini and Bruno (1996) showed that the size of simultaneous lightness contrast increases under Gelb lighting. To extend Agostini and Bruno’s work, we applied their methodology to a set of more spatially articulated displays. In four experiments, we investigated the role of spatial articulation on the size of the simultaneous lightness contrast effect. In the first experiment, we found a decrease of the simultaneous lightness contrast effect as the spatial articulation increased. In the second experiment (the control experiment), performed under homogeneous illumination, we found that the effect of spatial articulation is not detectable, even though the data seem to show the same trend as that in the previous experiment. In the third experiment, we found that spatial articulation affects not only the middle reflectance region, but also the lowest one. As the spatial articulation increases, the effect on the lightnesses of both regions decreases. In the last experiment, performed with a reduced range of reflectances, we found a lightening effect for all the reflectances and, again, an effect of spatial articulation. The results of these experiments are interpreted according to the model proposed by Gilchrist et al. (in press).

Measuring surface achromatic color: toward a common measure for increments and decrements.

Surface color is traditionally measured by matching methods. However, in some conditions, the color of certain surfaces cannot be measured: The surface simply looks brighter or darker than all the patches on a matching scale. We studied the reliability, validity, and range of application of three different types of simulated Munsell scales (white-, black-, and split-surrounded) as methods for measuring surface colors in simple disk-ring displays. All the scales were equally reliable for matching both increments and decrements, but about 20% of the increments were unmatchable on the white-surrounded scale, about 13% of the decrements were unmatchable on the black-surrounded scale, and about 9% of the increments were unmatchable on the split-surrounded scale. However, matches on all the scales were linearly related. Therefore, it is possible to convert them to common units, using regression parameters. These units provide an extended metric for measuring all increments and decrements in the stimulus space, effectively removing ceiling and floor effects, and providing measures even for surfaces that were perceived as out of range on some of the scales.

Modality and Perceptual-Motor Experience Influence the Detection of Temporal Deviations in Tap Dance Sequences

Accurate temporal information processing is critically important in many motor activities within disciplines such as dance, music, and sport. However, it is still unclear how temporal information related to biological motion is processed by expert and non-expert performers. It is well-known that the auditory modality dominates the visual modality in processing temporal information of simple stimuli, and that experts outperform non-experts in biological motion perception. In the present study, we combined these two areas of research; we investigated how experts and non-experts detected temporal deviations in tap dance sequences, in the auditory modality compared to the visual modality. We found that temporal deviations were better detected in the auditory modality compared to the visual modality, and by experts compared to non-experts. However, post hoc analyses indicated that these effects were mainly due to performances obtained by experts in the auditory modality. The results suggest that the experience advantage is not equally distributed across the modalities, and that tap dance experience enhances the effectiveness of the auditory modality but not the visual modality when processing temporal information. The present results and their potential implications are discussed in both temporal information processing and biological motion perception frameworks.

The Role of Sound in Motor Perception and Execution

“Perception and action” is one of the main research fields in which experimental psychologists work together with experts of other disciplines, such as medicine, physiotherapy, engineering, and sport. Traditionally, researchers have mainly focused on visual perception and on its influences on motor processes, while less attention has been dedicated to the role of auditory perception. However, in the last decade, the interest towards the influence of sounds on both action perception and motor execution has increased significantly. On the one hand, researchers have been interested in determining how humans can represent motor actions through the sounds associated with movements, as well as which auditory cues are salient for recognizing and discriminating different features of movement [1-10]. On the other hand, researchers have studied how auditory stimuli affect the production of complex movements in different domains [11-21]. The general aim of this special issue is to provide an overview of the relationship between sounds and movements by addressing theoretical, methodological, and applied issues from a multidisciplinary perspective.

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.