https://www.pisavisionlab.org Research centre dedicated to frontier, interdisciplinary research of human perception Wed, 24 Nov 2021 20:35:38 +0000 en-US hourly 1 https://wordpress.org/?v=6.4.13 https://www.pisavisionlab.org/2019/12/24/three-systems-for-visual-numerosity-a-single-case-study-neuropsychologia-136-107259/ Tue, 24 Dec 2019 14:10:39 +0000 https://www.pisavisionlab.org/?p=1440 Neuropsychologia, 136, 107259 Humans possess the remarkable capacity to assess the numerosity of a set of items over a wide range of conditions, from a handful of items to hundreds of them. Recent evidence is starting to show that judgments over such a large range is possible because of the presence of three mechanisms, each tailored to specific stimulation conditions. Previous evidence in favour of this theory comes from the fact that discrimination thresholds and estimation reaction times are not constants across numerosity levels. Likewise, attention is capable of dissociating the three mechanisms: when healthy adult observers are asked to perform concurrently a taxing task, the judgments of low numerosities (<4 dots) or of high numerosities is affected greatly, not so however for intermediate numerosities. Here we bring evidence from a neuropsychological perspective. To this end we measured perceptual performance in PA, a 41 year-old patient who suffers simultanagnosia after a hypoxic brain injury. PA showed a profound deficit in attentively tracking objects over space and time (multiple object tracking), even in very simple conditions where controls made no errors. PA also showed a massive deficit on sensory thresholds when comparing dot-arrays containing extremely low (3 dots) or extremely high (64, 128 dots) numerosities as well as in comparing dot-distances. Surprisingly, PA discrimination thresholds were relatively spared for intermediate numerosity (12 and 16 dots). Overall his deficit on the numerosity task results in a U-shape function across numerosity which, combined with the attentional deficit and the inability to judge dot-distances, confirms previously suggested three-systems for numerosity judgments. Anobile, G., Tomaiuolo, F., Campana, S., & Cicchini, G. M. https://www.pisavisionlab.org/2019/12/24/three-systems-for-visual-numerosity-a-single-case-study-neuropsychologia-136-107259/2019_anobile_thrresystemsfor/https://doi.org/10.1016/j.neuropsychologia.2019.107259 https://www.pisavisionlab.org/2020/05/24/prova-2020/ Sun, 24 May 2020 04:59:06 +0000 https://www.pisavisionlab.org/?p=2344 Journal of Vision 2020;20(3):3 In paradigms of visual search where the search feature (say color) can change from trial to trials, responses are faster for trials where the search color is repeated than when it changes. This is a clear example of “priming” of attention. Here we test whether the priming effects can be revealed by pupillometry, and also whether they are related to autistic-like personality traits, as measured by the Autism-Spectrum Quotient (AQ). We repeated Maljkovic and Nakayama's (1994) classic priming experiment, asking subjects to identify rapidly the shape of a singleton target defined by color. As expected, reaction times were faster when target color repeated, and the effect accumulated over several trials; but the magnitude of the effect did not correlate with AQ. Reaction times were also faster when target position was repeated, again independent of AQ. Presentation of stimuli caused the pupil to dilate, and the magnitude of dilation was greater for switched than repeated trials. This effect did not accumulate over trials, and did not correlate with the reaction times difference, suggesting that the two indexes measure independent aspects of the priming phenomenon. Importantly, the amplitude of pupil modulation correlated negatively with AQ, and was significant only for those participants with low AQ. The results confirm that pupillometry can track perceptual and attentional processes, and furnish useful information unobtainable from standard psychophysics, including interesting dependencies on personality traits. Pomè, A., Binda, P., Cicchini, G.M., Burr. D.C. (2020). https://www.pisavisionlab.org/2020/05/24/prova-2020/pupillometry-correlates-of-visual-priming-and-their-dependency-on-autistic-traits/https://doi.org/10.1167/jovi.20.3.3 https://www.pisavisionlab.org/2020/05/30/neuroplasticity-in-adult-human-visual-cortex-neuroscience-biobehavioral-reviews-volume-112-may-2020-pages-542-552/ Sat, 30 May 2020 13:47:26 +0000 https://www.pisavisionlab.org/?p=2386 Neuroscience & Biobehavioral Reviews, 112, 542–552 Between 1-5:100 people worldwide have never experienced normotypic vision due to a condition called amblyopia, and about 1:4000 suffer from inherited retinal dystrophies that progressively lead to blindness. While a wide range of technologies and therapies are being developed to restore vision, a fundamental question still remains unanswered: would the adult visual brain retain a sufficient plastic potential to learn how to ‘see’ after a prolonged period of abnormal visual experience? In this review we summarize studies showing that the visual brain of sighted adults retains a type of developmental plasticity, called homeostatic plasticity, and this property has been recently exploited successfully for adult amblyopia recovery. Next, we discuss how the brain circuits reorganize when blindness occurs and when visual stimulation is partially restored by means of a ‘bionic eye’ in late blind adults with Retinitis Pigmentosa. The primary visual cortex in these patients slowly became activated by the artificial visual stimulation, indicating that sight restoration therapies can rely on a considerable degree of spared plasticity in adulthood. Castaldi, E., Lunghi, C., & Morrone, M. C. https://www.pisavisionlab.org/2020/05/30/neuroplasticity-in-adult-human-visual-cortex-neuroscience-biobehavioral-reviews-volume-112-may-2020-pages-542-552/1-s2-0-s0149763419303288-main/https://doi.org/10.1016/j.neubiorev.2020.02.028 https://www.pisavisionlab.org/2020/05/31/motor-adaptation-distorts-visual-space/ Sun, 31 May 2020 04:29:47 +0000 https://www.pisavisionlab.org/?p=2394 Vision Research, 171, 31-35. It has been suggested that the human visual system exploits an adaptable metric to implement a precise but plastic spatial representation. Indeed, adapting to a dense dot-texture reduces the apparent separation of subsequently presented dots pairs. Whether this metric is purely visual or shared between senses is still unknown. Here we present a new cross-modal after-effect revealing that the metric with which the visual system computes the relative spatial position of objects is shared with the motor system. A few seconds of mid-air self-produced tapping movements (adaptation) yielded a robust compression of the apparent separation of dot pairs subsequently displayed around the tapping region. This visuo-motor spatial metric could reflect an efficient functional architecture to program and execute actions aimed at efficient interaction with the objects in the environment. Petrizzo, I., Anobile, G., & Arrighi, R. https://www.pisavisionlab.org/2020/05/31/motor-adaptation-distorts-visual-space/1-s2-0-s0042698920300675-main/https://doi.org/10.1016/j.visres.2020.04.007 https://www.pisavisionlab.org/2020/05/31/math-anxiety-mediates-the-link-between-number-sense-and-math-achievements-in-high-math-anxiety-young-adults/ Sun, 31 May 2020 04:33:28 +0000 https://www.pisavisionlab.org/?p=2396 Frontiers in Psychology, 11, 1095 In the past few years, many studies have suggested that subjects with high sensory precision in the processing of non-symbolic numerical quantities (approximate number system; ANS) also have higher math abilities. At the same time, there has been interest in another non-cognitive factor affecting mathematical learning: mathematical anxiety (MA). MA is defined as a debilitating emotional reaction to mathematics that interferes with the manipulation of numbers and the solving of mathematical problems. Few studies have been dedicated to uncovering the interplay between ANS and MA and those have provided conflicting evidence. Here we measured ANS precision (numerosity discrimination thresholds) in a cohort of university students with either a high (>75th percentile; n = 49) or low (<25th percentile; n = 39) score on the Abbreviate Math Anxiety Scale (AMAS). We also assessed math proficiency using a standardized test (MPP: Mathematics Prerequisites for Psychometrics), visuo-spatial attention capacity by means of a Multiple Objects Tracking task (MOT) and sensory precision for non-numerical quantities (disk size). Our results confirmed previous studies showing that math abilities and ANS precision correlate in subjects with high math anxiety. Neither precision in size-discrimination nor visuo-spatial attentional capacity were found to correlate with math capacities. Interestingly, within the group with high MA, our data also revealed a relationship between ANS precision and MA, with MA playing a key role in mediating the correlation between ANS and math achievement. Taken together, our results suggest an interplay between extreme levels of MA and the sensory precision in the processing of non-symbolic numerosity. Maldonado Moscoso, P. A., Anobile, G., Primi, C., & Arrighi, R. https://www.pisavisionlab.org/2020/05/31/math-anxiety-mediates-the-link-between-number-sense-and-math-achievements-in-high-math-anxiety-young-adults/fpsyg-11-01095/https://doi.org/10.3389/fpsyg.2020.01095 https://www.pisavisionlab.org/2020/06/30/the-common-rhythm-of-action-and-perception-journal-of-cognitive-neuroscience-2/ Tue, 30 Jun 2020 18:41:17 +0000 https://www.pisavisionlab.org/?p=2666 Journal of Cognitive Neuroscience, 32(2), 187–200. 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. Benedetto, A., Morrone, M. C., & Tomassini, A. https://www.pisavisionlab.org/2020/06/30/the-common-rhythm-of-action-and-perception-journal-of-cognitive-neuroscience-2/2020-jcogneurosci/https://doi.org/10.1162/jocn_a_01436 https://www.pisavisionlab.org/2020/07/21/serial-dependence-in-perception-requires-conscious-awareness/ Tue, 21 Jul 2020 06:04:20 +0000 https://www.pisavisionlab.org/?p=3036 Current Biology 30, R237–R262, March 23, 2020 Current visual perception is systematically biased towards the immediate past, an effect known as serial dependence. A variety of basic visual features, including orientation, motion and numerosity, show serial dependence, but it remains unclear whether perceptual awareness is necessary. We address this question by combining serial dependence for orientation with binocular rivalry between orthogonal gratings. Fourteen participants viewed trial sequences which alternated between rivalrous presentations, with orthogonal gratings to each eye, and monocularly presented test gratings. Participants indicate the orientation of the stimuli – either the dominant percept in rivalry or the orientation of the test – by matching with a rotatable line. Half of the rivalry trials were selected (at random) for the “dominant” condition, half for the “supressed” condition. The subsequent test was presented to the appropriate eye (dominant or suppressed) at an orientation rotated ±10° from the chosen rivalrous stimulus. We found that orientation estimates were strongly biased towards the preceding trial (positive serial dependence), but only in the dominance condition, not in the suppression condition. These results were replicated with test gratings presented binocularly in a separate experiment. These results show that only if stimuli are consciously perceived will they act as a prior to bias subsequent perception, suggesting that construction of the prior occurs at a relatively high level. However, the results do not speak to the issue of the stage of analysis where the prior distorts incoming sensory information. Sujin Kim, David Burr, Guido Marco Cicchini, David Alais https://www.pisavisionlab.org/2020/07/21/serial-dependence-in-perception-requires-conscious-awareness/kimetal_currbio2020/https://doi.org/10.1016/j.cub.2020.02.008 https://www.pisavisionlab.org/2020/08/24/groupitizing-a-strategy-for-numerosity-estimation/ Mon, 24 Aug 2020 15:13:43 +0000 https://www.pisavisionlab.org/?p=3100 Scientific Reports, 10(1), 13436 Previous work has shown that when arrays of objects are grouped within clusters, participants can enumerate their numerosity more rapidly than when objects are randomly scattered, a phenomenon termed “groupitizing”. Importantly, the magnitude of the grouping advantage correlates with math abilities in children. Here we show that sensory precision of numerosity estimation is also improved when grouping cues are available, by up to 20%. The grouping can be induced by color and/or spatial proximity, and occurs in temporal sequences as well as spatial arrays. The improvement is strongest for participants with the highest thresholds in the random, ungrouped conditions. Taken together with previous research, our data suggest that measurements correlations between numerosity estimation and formal math skills may be driven by grouping strategies, which require a minimal level of basic arithmetic. Anobile, G., Castaldi, E., Moscoso, P. A. M., Burr, D. C., & Arrighi, R. https://www.pisavisionlab.org/2020/08/24/groupitizing-a-strategy-for-numerosity-estimation/s41598-020-68111-1/https://doi.org/10.1038/s41598-020-68111-1 https://www.pisavisionlab.org/2020/08/24/adaptation-to-hand-tapping-affects-sensory-processing-of-numerosity-directly-evidence-from-reaction-times-and-confidence-2/ Mon, 24 Aug 2020 16:12:44 +0000 https://www.pisavisionlab.org/?p=3115 Proceedings of the Royal Society B: Biological Sciences, 287(1927), 20200801 Like most perceptual attributes, the perception of numerosity is susceptible to adaptation, both to prolonged viewing of spatial arrays and to repeated motor actions such as hand-tapping. However, the possibility has been raised that adaptation may reflect response biases rather than modification of sensory processing. To disentangle these two possibilities, we studied visual and motor adaptation of numerosity perception while measuring confidence and reaction times. Both sensory and motor adaptation robustly distorted numerosity estimates, and these shifts in perceived numerosity were accompanied by similar shifts in confidence and reaction-time distributions. After adaptation, maximum uncertainty and slowest response-times occurred at the point of subjective (rather than physical) equality of the matching task, suggesting that adaptation acts directly on the sensory representation of numerosity, before the decisional processes. On the other hand, making reward response-contingent, which also caused robust shifts in the psychometric function, caused no significant shifts in confidence or reaction-time distributions. These results reinforce evidence for shared mechanisms that encode the quantity of both internally and externally generated events, and advance a useful general technique to test whether contextual effects like adaptation and serial dependence really affect sensory processing. Maldonado Moscoso, P. A., Cicchini, G. M., Arrighi, R., & Burr, D. C. https://www.pisavisionlab.org/2020/08/24/adaptation-to-hand-tapping-affects-sensory-processing-of-numerosity-directly-evidence-from-reaction-times-and-confidence-2/adaptation-to-hand-tapping-affects-sensory-processing-of-numerosity-directly-evidence-from-reaction-times-and-confidence-2/https://doi.org/10.1098/rspb.2020.0801 https://www.pisavisionlab.org/2020/08/25/the-visual-white-matter-connecting-human-area-prostriata-and-the-thalamus-is-retinotopically-organized/ Tue, 25 Aug 2020 08:55:37 +0000 https://www.pisavisionlab.org/?p=3132 Brain Structure and Function, 1-15 The human visual system is capable of processing visual information from fovea to the far peripheral visual feld. Recent fMRI studies have shown a full and detailed retinotopic map in area prostriata, located ventro-dorsally and anterior to the calcarine sulcus along the parieto-occipital sulcus with strong preference for peripheral and wide-feld stimulation. Here, we report the anatomical pattern of white matter connections between area prostriata and the thalamus encompassing the lateral geniculate nucleus (LGN). To this end, we developed and utilized an automated pipeline comprising a series of Apps that run openly on the cloud computing platform brainlife.io to analyse 139 subjects of the Human Connectome Project (HCP). We observe a continuous and extended bundle of white matter fbers from which two subcomponents can be extracted: one passing ventrally parallel to the optic radiations (OR) and another passing dorsally circumventing the lateral ventricle. Interestingly, the loop travelling dorsally connects the thalamus with the central visual feld representation of prostriata located anteriorly, while the other loop travelling more ventrally connects the LGN with the more peripheral visual feld representation located posteriorly. We then analyse an additional cohort of 10 HCP subjects using a manual plane extraction method outside brainlife.io to study the relationship between the two extracted white matter subcomponents and eccentricity, myelin and cortical thickness gradients within prostriata. Our results are consistent with a retinotopic segregation recently demonstrated in the OR, connecting the LGN and V1 in humans and reveal for the frst time a retinotopic segregation regarding the trajectory of a fber bundle between the thalamus and an associative visual area. JW Kurzawski, K Mikellidou, MC Morrone, F Pestilli https://www.pisavisionlab.org/2020/08/25/the-visual-white-matter-connecting-human-area-prostriata-and-the-thalamus-is-retinotopically-organized/the_visual_white_matter_connecting_human_area_pros/https://doi.org/10.1007/s00429-020-02096-5 https://www.pisavisionlab.org/2020/09/24/fast-saccadic-eye-movements-in-humans-suggest-that-numerosity-perception-is-automatic-and-direct/ Thu, 24 Sep 2020 13:00:59 +0000 https://www.pisavisionlab.org/?p=3160 Proceedings of the Royal Society B: Biological Sciences, 287(1935), 20201884 Fast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discriminate numerosities with high accuracy and great speed, as fast as 190 ms. Intermediate numerosities were more likely to elicit fast saccades than very low or very high numerosities. Reaction-times for vocal responses (collected in a separate experiment) were slower, did not depend on numerical range, and correlated only with the slow not the fast saccades, pointing to different systems. The short saccadic reaction-times we observe are surprising given that discrimination using numerosity estimation is thought to require a relatively complex neural circuit, with several relays of information through the parietal and prefrontal cortex. Our results suggest that fast numerosity-driven saccades may be generated on a single feed-forward pass of information recruiting a primitive system that cuts through the cortical hierarchy and rapidly transforms the numerosity information into a saccade command. Castaldi, E., Burr, D., Turi, M., & Binda, P. https://www.pisavisionlab.org/2020/09/24/fast-saccadic-eye-movements-in-humans-suggest-that-numerosity-perception-is-automatic-and-direct/rspb-2020-1884/https://doi.org/10.1098/rspb.2020.1884 https://www.pisavisionlab.org/2020/10/09/spontaneous-pupillary-oscillations-increase-during-mindfulness-meditation/ Fri, 09 Oct 2020 14:37:09 +0000 https://www.pisavisionlab.org/?p=3218 Current Biology Volume 30, Issue 18, 21 September 2020, Pages R1030-R1031 A significant body of literature has shown that pupil size varies with cognitive and perceptual states [1,2]. Furthermore, the pupil diameter oscillates spontaneously at low frequencies, sometimes referred to as pupillary hippus [3,4]. Oscillation amplitude varies with many neural factors, including arousal and cortical excitability. Here we show that pupillary oscillations are modulated by mindfulness meditation, increasing by 53% compared to pre- and post-meditation baselines. The effect occurs only in trained meditators and is specific for low frequencies (below 1 Hz), with delta frequencies (1–5 Hz) unchanged. The study suggests that pupil size may be a useful marker of the altered cortical state during meditation. Antonella Pomè, David C.Burr, Annalisa Capuozzo, Paola Binda https://www.pisavisionlab.org/2020/10/09/spontaneous-pupillary-oscillations-increase-during-mindfulness-meditation/1-s2-0-s0960982220310897-main/https://doi.org/10.1016/j.cub.2020.07.064 https://www.pisavisionlab.org/2020/10/09/adaptation-to-the-speed-of-biological-motion-in-autism-2/ Fri, 09 Oct 2020 14:47:27 +0000 https://www.pisavisionlab.org/?p=3224 Journal of Autism and Developmental Disorders, 50(2), 373–385 Autistic individuals often present atypicalities in adaptation—the continuous recalibration of perceptual systems driven by recent sensory experiences. Here, we examined such atypicalities in human biological motion. We used a dual-task paradigm, including a running-speed discrimination task (‘comparing the speed of two running silhouettes’) and a change-detection task (‘detecting fixation-point shrinkages’) assessing attention. We tested 19 school-age autistic and 19 age- and ability-matched typical participants, also recording eye-movements. The two groups presented comparable speed-discrimination abilities and, unexpectedly, comparable adaptation. Accuracy in the change-detection task and the scatter of eye-fixations around the fixation point were also similar across groups. Yet, the scatter of fixations reliably predicted the magnitude of adaptation, demonstrating the importance of controlling for attention in adaptation studies. Karaminis, T., Arrighi, R., Forth, G., Burr, D., & Pellicano, E. https://www.pisavisionlab.org/2020/10/09/adaptation-to-the-speed-of-biological-motion-in-autism-2/karaminis2020_article_adaptationtothespeedofbiologic/https://doi.org/10.1007/s10803-019-04241-4 https://www.pisavisionlab.org/2020/10/09/grouping-strategies-in-number-estimation-extend-the-subitizing-range/ Fri, 09 Oct 2020 14:58:57 +0000 https://www.pisavisionlab.org/?p=3235 Scientific Reports, 10(1), 14979 When asked to estimate the number of items in a visual array, educated adults and children are more precise and rapid if the items are clustered into small subgroups rather than randomly distributed. This phenomenon, termed “groupitizing”, is thought to rely on the recruitment of the subitizing system (dedicated to the perception of very small numbers), with the aid of simple arithmetical calculations. The aim of current study is to verify whether the advantage for clustered stimuli does rely on subitizing, by manipulating attention, known to strongly affect attention. Participants estimated the numerosity of grouped or ungrouped arrays in condition of full attention or while attention was diverted with a dual-task. Depriving visual attention strongly decreased estimation precision of grouped but not of ungrouped arrays, as well as increasing the tendency for numerosity estimation to regress towards the mean. Additional explorative analyses suggested that calculation skills correlated with the estimation precision of grouped, but not of ungrouped, arrays. The results suggest that groupitizing is an attention-based process that leverages on the subitizing system. They also suggest that measuring numerosity estimation thresholds with grouped stimuli may be a sensitive correlate of math abilities. Maldonado Moscoso, P. A., Castaldi, E., Burr, D. C., Arrighi, R., & Anobile, G. https://www.pisavisionlab.org/2020/10/09/grouping-strategies-in-number-estimation-extend-the-subitizing-range/s41598-020-71871-5/https://doi.org/10.1038/s41598-020-71871-5 https://www.pisavisionlab.org/2020/10/09/object-identity-determines-trans-saccadic-integration/ Fri, 09 Oct 2020 15:04:10 +0000 https://www.pisavisionlab.org/?p=3245 Journal of Vision July 2020, Vol.20, 33 Humans make two to four rapid eye movements (saccades) per second, which, surprisingly, does not lead to abrupt changes in vision. To the contrary, we perceive a stable world. Hence, an important question is how information is integrated across saccades. To investigate this question, we used the sequential metacontrast paradigm (SQM), where two expanding streams of lines are presented. When one line is spatially offset, the other lines are perceived as being offset, too. When more lines are offset, all offsets integrate mandatorily; that is, observers cannot report the individual offsets but perceive one integrated offset. Here, we asked observers to make a saccade during the SQM. Even though the saccades caused a highly disrupted motion trajectory on the retina, offsets presented before and after the saccade integrated mandatorily. When observers made no saccade and the streams were displaced on the screen so that a similarly disrupted retinal image occurred as in the previous condition, no integration occurred. We suggest that trans-saccadic integration and perception are determined by object identity in spatiotopic coordinates and not by the retinal image. Leila Drissi-Daoudi; Haluk Öğmen; Michael H. Herzog; Guido Marco Cicchini https://www.pisavisionlab.org/2020/10/09/object-identity-determines-trans-saccadic-integration/i0035-8711-719-1-07244/https://doi.org/10.1167/jov.20.7.33 https://www.pisavisionlab.org/2020/10/09/perceptual-oscillations-in-gender-classification-of-faces-contingent-on-stimulus-history/ Fri, 09 Oct 2020 15:06:15 +0000 https://www.pisavisionlab.org/?p=3249 iScience Volume 23, Issue 10, 23 October 2020, 101573 Perception is a proactive ‘‘predictive’’ process, in which the brain takes advantage of past experience to make informed guesses about the world to test against sensory data. Here we demonstrate that in the judgment of the gender of faces, beta rhythms play an important role in communicating perceptual experience. Observers classified in forced choice as male or female, a sequence of face stimuli, which were physically constructed to be male or female or androgynous (equal morph). Classification of the androgynous stimuli oscillated rhythmically between male and female, following a complex waveform comprising 13.5 and 17 Hz. Parsing the trials based on the preceding stimulus showed that responses to androgynous stimuli preceded by male stimuli oscillated reliably at 17 Hz, whereas those preceded by female stimuli oscillated at 13.5 Hz. These results suggest that perceptual priors for face perception from recent perceptual memory are communicated through frequency-coded beta rhythms. Jason Bell, David C.Burr, Kate Crookes, Maria Concetta Morrone https://www.pisavisionlab.org/2020/10/09/perceptual-oscillations-in-gender-classification-of-faces-contingent-on-stimulus-history/1-s2-0-s2589004220307653-main/https://doi.org/10.1016/j.isci.2020.101573 https://www.pisavisionlab.org/2020/10/09/the-shared-numerical-representation-for-action-and-perception-develops-independently-from-vision-2/ Fri, 09 Oct 2020 15:14:43 +0000 https://www.pisavisionlab.org/?p=3269 Cortex, 129, 436–445 Humans share with other animals a number sense, a system allowing a rapid and approximate estimate of the number of items in a scene. Recently, it has been shown that numerosity is shared between action and perception as the number of repetitions of self-produced actions affects the perceived numerosity of subsequent visual stimuli presented around the area where actions occurred. Here we investigate whether this interplay between action and perception for numerosity depends on visual input and visual experience. We measured the effects of adaptation to motor routines (finger tapping) on numerical estimates of auditory sequences in sighted and congenitally blind people. In both groups, our results show a consistent adaptation effect with relative under- or over-estimation of perceived auditory numerosity following rapid or slow tapping adaptation, respectively. Moreover, adaptation occurred around the tapping area irrespective of the hand posture (crossed or uncrossed hands), indicating that motor adaptation was coded using external (not hand-centred) coordinates in both groups. Overall, these results support the existence of a generalized interaction between action and perception for numerosity that occurs in external space and manifests independently of visual input or even visual experience. Togoli, I., Crollen, V., Arrighi, R., & Collignon, O. https://www.pisavisionlab.org/2020/10/09/the-shared-numerical-representation-for-action-and-perception-develops-independently-from-vision-2/1-s2-0-s001094522030191x-main/https://doi.org/10.1016/j.cortex.2020.05.004 https://www.pisavisionlab.org/2020/11/16/location-and-object-based-attention-enhance-number-estimation/ Mon, 16 Nov 2020 09:55:43 +0000 https://www.pisavisionlab.org/?p=3382 Atten Percept Psychophys (2020) Humans and non-humans can extract an estimate of the number of items in a collection very rapidly, raising the question of whether attention is necessary for this process. Visual attention operates in various modes, showing selectivity both to spatial location and to objects. Here, we tested whether each form of attention can enhance number estimation, by measuring whether presenting a visual cue to increase attentional engagement will lead to a more accurate and precise representation of number, both when attention is directed to location and when it is directed to objects. Results revealed that enumeration of a collection of dots in the location previously cued led to faster, more precise, and more accurate judgments than enumeration in un-cued locations, and a similar benefit was seen when the cue and collection appeared on the same object. This work shows that like many other perceptual tasks, numerical estimation may be enhanced by the spread of active attention inside a pre-cued object. Antonella Pomè, Diego Thompson, David Charles Burr & Justin Halberda https://www.pisavisionlab.org/2020/11/16/location-and-object-based-attention-enhance-number-estimation/pome2020_article_location-andobject-basedattent/https://doi.org/10.3758/s13414-020-02178-w https://www.pisavisionlab.org/2020/11/17/pupillary-responses-obey-emmerts-law-and-co-vary-with-autistic-traits/ Tue, 17 Nov 2020 17:09:34 +0000 https://www.pisavisionlab.org/?p=3389 J Autism Dev Disord (2020) We measured the pupil response to a light stimulus subject to a size illusion and found that stimuli perceived as larger evoke a stronger pupillary response. The size illusion depends on combining retinal signals with contextual 3D information; contextual processing is thought to vary across individuals, being weaker in individuals with stronger autistic traits. Consistent with this theory, autistic traits correlated negatively with the magnitude of pupil modulations in our sample of neurotypical adults; however, psychophysical measurements of the illusion did not correlate with autistic traits, or with the pupil modulations. This shows that pupillometry provides an accurate objective index of complex perceptual processes, particularly useful for quantifying interindividual differences, and potentially more informative than standard psychophysical measures. Chiara Tortelli, Marco Turi, David C. Burr & Paola Binda https://www.pisavisionlab.org/2020/11/17/pupillary-responses-obey-emmerts-law-and-co-vary-with-autistic-traits/tortelli2020_article_pupillaryresponsesobeyemmertsl/https://doi.org/10.1007/s10803-020-04718-7 https://www.pisavisionlab.org/2020/11/23/a-sensorimotor-numerosity-system/ Mon, 23 Nov 2020 09:32:20 +0000 https://www.pisavisionlab.org/?p=3471 Trends in Cognitive Sciences, 25(1), 24–36 Incoming sensory input provides information for the planning and execution of actions, which yield motor outcomes that are themselves sensory inputs. One dimension where action and perception strongly interact is numerosity perception. Many non-human animals can estimate approximately the number of external elements as well as their own actions, and neurons have been identified that respond to both. Recent psychophysical adaptation studies on humans also provide evidence for neural mechanisms responding to both the number of externally generated events and self-produced actions. Here we advance the idea that these strong connections may arise from dedicated sensorimotor mechanisms in the brain, part of a more generalized system interfacing action with the processing of other quantitative magnitudes such as space and time. Anobile, G., Arrighi, R., Castaldi, E., & Burr, D. C. https://www.pisavisionlab.org/2020/11/23/a-sensorimotor-numerosity-system/1-s2-0-s1364661320302709-main/https://doi.org/10.1016/j.tics.2020.10.009 https://www.pisavisionlab.org/2020/11/26/pupillary-response-to-representations-of-light-in-paintings/ Thu, 26 Nov 2020 15:02:50 +0000 https://www.pisavisionlab.org/?p=3483 Journal of Vision, 20(10), 14–14. It is known that, although the level of light is the primary determinant of pupil size, cognitive factors can also affect pupil diameter. It has been demonstrated that photographs of the sun produce pupil constriction independently of their luminance and other low-level features, suggesting that high-level visual processing may also modulate pupil response. Here, we measure pupil response to artistic paintings of the sun, moon, or containing a uniform lighting, that, being mediated by the artist’s interpretation of reality and his technical rendering, require an even higher level of interpretation compared with photographs. We also study how chromatic content and spatial layout affect the results by presenting grey-scale and inverted versions of each painting. Finally, we assess directly with a categorization test how subjective image interpretation affects pupil response. We find that paintings with the sun elicit a smaller pupil size than paintings with the moon, or paintings containing no visible light source. The effect produced by sun paintings is reduced by disrupting contextual information, such as by removing color or manipulating the relations between paintings features that make more difficult to identify the source of light. Finally, and more importantly, pupil diameter changes according to observers’ interpretation of the scene represented in the same stimulus. In conclusion, results show that the subcortical pupillary response to light is modulated by subjective interpretation of luminous objects, suggesting the involvement of cortical systems in charge of cognitive processes, such as attention, object recognition, familiarity, memory, and imagination. Castellotti, S., Conti, M., Feitosa-Santana, C., & Del Viva, M. M. https://www.pisavisionlab.org/2020/11/26/pupillary-response-to-representations-of-light-in-paintings/i1534-7362-20-10-14_1602668521-01028/ https://doi.org/10.1167/jov.20.10.14 https://www.pisavisionlab.org/2020/12/16/not-only-faces-specialized-visual-representation-of-human-hands-revealed-by-adaptation/ Wed, 16 Dec 2020 15:49:52 +0000 https://www.pisavisionlab.org/?p=3510 Royal Society, Open Science Classical neurophysiological studies demonstrated that the monkey brain is equipped with neurons selectively representing the visual shape of the primate hand. Neuroimaging in humans provided data suggesting that a similar representation can be found in humans. Here, we investigated the selectivity of hand representation in humans by means of the visual adaptation technique. Results showed that participants' judgement of human-likeness of a visual probe representing a human hand was specifically reduced by a visual adaptation procedure when using a human hand adaptor but not when using an anthropoid robotic hand or a non-primate animal paw adaptor. Instead, human-likeness of the anthropoid robotic hand was affected by both human and robotic adaptors. No effect was found when using a non-primate animal paw as adaptor or probe. These results support the existence of specific neural mechanisms encoding human hand in the human's visual system. Massimiliano Conson, Francesco Polito, Alessandro Di Rosa, Luigi Trojano, Gennaro Cordasco, Anna Esposito and Marco Turi https://www.pisavisionlab.org/2020/12/16/not-only-faces-specialized-visual-representation-of-human-hands-revealed-by-adaptation/rsos-200948/https://doi.org/10.1098/rsos.200948 https://www.pisavisionlab.org/2021/01/12/perceptual-history-propagates-down-to-early-levels-of-sensory-analysis/ Tue, 12 Jan 2021 08:50:03 +0000 https://www.pisavisionlab.org/?p=3544 Current Biology, 31(6), 1245-1250.e2. One function of perceptual systems is to construct and maintain a reliable representation of the environment. A useful strategy intrinsic to modern “Bayesian” theories of perception1, 2, 3, 4, 5, 6 is to take advantage of the relative stability of the input and use perceptual history (priors) to predict current perception. This strategy is efficient1, 2, 3, 4, 5, 6, 7 but can lead to stimuli being biased toward perceptual history, clearly revealed in a phenomenon known as serial dependence.8, 9, 10, 11, 12, 13, 14 However, it is still unclear whether serial dependence biases sensory encoding or only perceptual decisions.15,16 We leveraged on the “surround tilt illusion”—where tilted flanking stimuli strongly bias perceived orientation—to measure its influence on the pattern of serial dependence, which is typically maximal for similar orientations of past and present stimuli.7,10 Maximal serial dependence for a neutral stimulus preceded by an illusory one occurred when the perceived, not the physical, orientations of the two stimuli matched, suggesting that the priors biasing current perception incorporate the effect of the illusion. However, maximal serial dependence of illusory stimuli induced by neutral stimuli occurred when their physical (not perceived) orientations were matched, suggesting that priors interact with incoming sensory signals before they are biased by flanking stimuli. The evidence suggests that priors are high-level constructs incorporating contextual information, which interact directly with early sensory signals, not with highly processed perceptual representations. Cicchini, G. M., Benedetto, A., & Burr, D. C. https://www.pisavisionlab.org/2021/01/12/perceptual-history-propagates-down-to-early-levels-of-sensory-analysis/1-s2-0-s0960982220318248-main/https://doi.org/10.1016/j.cub.2020.12.004 https://www.pisavisionlab.org/2021/11/24/subitizing-unlike-estimation-does-not-process-sets-in-parallel/ Wed, 24 Nov 2021 20:35:31 +0000 https://www.pisavisionlab.org/?p=3986 Scientific Reports, 10(1), 15689 Enumeration of very small quantities is a common task that we perform everyday. Much research has highlighted that in these conditions humans display fast, near errorless performance, a phenomenon dubbed subitizing. It has been suggested that this regime has a pivotal role in numerosity perception. Here we asked if this system can process multiple sets of items in parallel. At odds with what happens for moderate numerosities, we found a strong impairment caused already by the introduction of a second group of items marked by a different color. Adding shape as a cue provided no benefit. The only case in which subitizing was possible was when the target and distractor group were held constant through the experimental block. These results show the surprising fact that whilst being rapid and errorless, subitizing does not have the capability to disentangle multiple groups of items and deals only with coarse stimulus statistics. Liu, W., Zheng, P., Huang, S., & Cicchini, G. M. https://www.pisavisionlab.org/2021/11/24/subitizing-unlike-estimation-does-not-process-sets-in-parallel/s41598-020-72860-4/https://doi.org/10.1038/s41598-020-72860-4