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...... 2018 pisavisionlab scaled Paula Andrea Maldonado Moscoso Cecilia Steinwurzel Paola Binda Luca Lo Verde Irene Togoli Alessandro Benedetto Akshatha Bhat Roberto Arrighi Maria Concetta Morrone David Burr Guido Marco Cicchini Tam Ho Giovanni Anobile Antonella Pomè Claudia Lunghi Francesca Tinelli Kyriaki Mikellidou Jan Kurzawski Marco Turi Elisa Castaldi ERC ECSPLAIN About PisaVisionLab ....

New Research published on Attention, Perception & Psychophysics!

Congratulation to Antonella, Giovanni, Marco and Daivid for their last publication on Attention, Perception & Psychophysics!

Pomè, A., Anobile, G., Cicchini, G. M., Scabia, A. & Burr, D. C. (2019). Higher attentional costs for numerosity estimation at high densities, Attention, Perception, & Psychophysics, PDF

Humans can estimate numerosity over a large range, but the precision with which they do so varies considerably over that range. For very small sets, within the subitizing range of up to about four items, estimation is rapid and errorless. For intermediate numerosities, errors vary directly with the numerosity, following Weber’s law, but for very high numerosities, with very dense patterns, thresholds continue to rise with the square root of numerosity. This suggests that three different mechanisms operate over the number range. In this study we provide further evidence for three distinct numerosity mechanisms, by studying their dependence on attentional resources. We measured discrimination thresholds over a wide range of numerosities, while manipulating attentional load with both visual and auditory dual tasks. The results show that attentional effects on thresholds vary over the number range. Both visual and auditory attentional loads strongly affect subitizing, much more than for larger numerosities. Attentional costs remain stable over the estimation range, then rise again for very dense patterns. These results reinforce the idea that numerosity is processed by three separates but probably overlapping systems.

New Research published on Journal of Cognitive Neuroscience!

Congratulation to AlessandroConcetta and Alice who just published a new paper on Journal of Cognitive Neuroscience!

Benedetto, A., Morrone, C. & Tomassini, A. (2019). The Common Rhythm of Action and Perception., Journal of Cognitive Neuroscience, PDF

Research in the last decade has undermined the idea of perception as a continuous process, providing strong empirical support for its rhythmic modulation. More recently, it has been revealed that the ongoing motor processes influence the rhythmic sampling of sensory information. In this review, we will focus on a growing body of evidence suggesting that oscillation-based mechanisms may structure the dynamic interplay between the motor and sensory system and provide a unified temporal frame for their effective coordination. We will describe neurophysiological data, primarily collected in animals, showing phase-locking of neuronal oscillations to the onset of (eye) movements. These data are complemented by novel evidence in humans, which demonstrate the behavioral relevance of these oscillatory modulations and their domain-general nature. Finally, we will discuss the possible implications of these modulations for action-perception coupling mechanisms.


New Research published on Behavioral and Brain Sciences!

Congratulation to Marco and David who just published a new paper on Behavioral and Brain Science!

Cicchini, G. M. & Burr, D. (2018). Serial Effects are optimal, Behavioral and Brain Sciences, (41), PDF

In the target article, Rahnev & Denison (R&D) use serial effects as an example of suboptimality. We show here that serial effects can be beneficial to perception, serving to reduce both error and response times in a near-optimal fashion. Furthermore, serial effects for stable attributes are positive, whereas those for changeable attributes are negative, demonstrating that they are engaged flexibly to optimize performance.


New Research published on Neuropsychologia!

Congratulation to Giovanni, Marco and David who just published a new paper on Neuropsychologia!

Anobile, G., Cicchini, G. M., Gasperini, F. & Burr, D. (2018). Typical numerosity adaptation despite selectively impaired number acuity in dyscalculia, Neuropsychologia, PDF

It has been suggested that a core deficit of the “number sense” may underlie dyscalculia. We test this idea by measuring perceptual adaptation and discrimination thresholds for numerosity and object size in a group of dyscalculic and typical preadolescents (N=71, mean age 12). We confirmed that numerosity discrimination thresholds are higher in evelopmental dyscalculia, while size thresholds are not affected. However, dyscalculics adapted to numerosity in a similar way to typicals. This suggests that although numerosity thresholds are selectively higher in dyscalculia, the mechanisms for perceiving numerosity are otherwise similar, suggesting that that have a similar, but perhaps noisier, number sense.

2018 giovanniNeuropsychologia



New Research published on the Proceedings of the Royal Society of London B!

Congratulation to Marco, Koulla and David who just published a new paper on Proc. R. Soc. B!

Cicchini, G. M., Mikellidou, K. & Burr, D. (2018). The functional role of serial dependence, Proceedings of the Royal Society of London B, PDF

The world tends to be stable from moment to moment, leading to strong serial correlations in natural scenes. As similar stimuli usually require similar behavioral responses, it is highly likely that the brain has developed strategies to leverage these regularities. A good deal of recent psychophysical evidence is beginning to show that the brain is sensitive to serial correlations, causing strong drifts in observer responses towards previously seen stimuli. However, it is still not clear that this tendency leads to a functional advantage. Here we test a formal model of optimal serial dependence and show that as predicted, serial dependence in an orientation reproduction task is dependent on current stimulus reliability, with less precise stimuli, such as low spatial frequency oblique Gabors, exhibiting the strongest effects. We also show that serial dependence depends on the similarity between two successive stimuli, again consistent with behavior of an ideal observer aiming at minimizing reproduction errors. Lastly, we show that serial dependence leads to faster response times, indicating that the benefits of serial integration go beyond reproduction error. Overall our data show that serial dependence has a beneficial role at various levels of perception, consistent with the idea that the brain exploits temporal redundancy of the visual scene as an optimization strategy



New Review published in Annual Review of Vision Science!

Congratulations to Paola and Concetta for the new publication!

Binda, P. & Morrone, M. C. (2018). Vision During Saccadic Eye Movements, Annual Review of Vision Science, 1 (4), 193-213. PDF

The perceptual consequences of eye movements are manifold: Each large saccade is accompanied by a drop of sensitivity to luminance-contrast, low-frequency stimuli, impacting both conscious vision and involuntary responses, including pupillary constrictions. They also produce transient distortions of space, time, and number, which cannot be attributed to the mere motion on the retinae. All these are signs that the visual system evokes active processes to predict and counteract the consequences of saccades. We propose that a key mechanism is the reorganization of spatiotemporal visual fields, which transiently increases the temporal and spatial uncertainty of visual representations just before and during saccades. On one hand, this accounts for the spatiotemporal distortions of visual perception; on the other hand, it implements a mechanism for fusing pre- and postsaccadic stimuli. This, together with the active suppression of motion signals, ensures the stability and continuity of our visual experience.

New Research published in Scientific Reports!

Congratulations to Giovanni, David and Marco  for the new publication!

Anobile, G., Burr, D. C., Iaia, M., Marinelli, C. V., Angelelli, P. & Turi, M. (2018). Independent adaptation mechanisms for numerosity and size perception provide evidence against a common sense of magnitude, Sci Rep, 1 (8), 13571. PDF

How numerical quantity is processed is a central issue for cognition. On the one hand the "number sense theory" claims that numerosity is perceived directly, and may represent an early precursor for acquisition of mathematical skills. On the other, the "theory of magnitude" notes that numerosity correlates with many continuous properties such as size and density, and may therefore not exist as an independent feature, but be part of a more general system of magnitude. In this study we examined interactions in sensitivity between numerosity and size perception. In a group of children, we measured psychophysically two sensory parameters: perceptual adaptation and discrimination thresholds for both size and numerosity. Neither discrimination thresholds nor adaptation strength for numerosity and size correlated across participants. This clear lack of correlation (confirmed by Bayesian analyses) suggests that numerosity and size interference effects are unlikely to reflect a shared sensory representation. We suggest these small interference effects may rather result from top-down phenomena occurring at late decisional levels rather than a primary "sense of magnitude".

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