https://www.pisavisionlab.org Research centre dedicated to frontier, interdisciplinary research of human perception Thu, 22 Apr 2021 10:01:21 +0000 en-US hourly 1 https://wordpress.org/?v=6.4.13 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/2020/07/13/motor-adaptation-distorts-space/ Mon, 13 Jul 2020 09:25:38 +0000 https://www.pisavisionlab.org/?p=2804 ["poster"] European Workshop on Cognitive Neuropsychology EWCN 2020, Bressanone Introduction : It has been recently demonstrated that adapting to self-produced motion induces a compression of both perceived numerosity and duration. These results suggest the existence of visuomotor mechanisms that encode numerosity and duration of external as well as internal events. However, according to the ATOM theory, the perception of time and numerosity might also be linked to the processing of spatial information, with all these dimensions tapping a common neural mechanism. To test this hypothesis, we assessed whether motor adaptation also affects the perception of visual stimuli distance, and compared these results to visual adaptation (to high density texture), which is known to distort spatial separation.<br>Methods : We measured the effects of visual and motor adaptation on the perceived separation of dots. Participants were presented with two vertically aligned dot pairs, separated by about 4° (with random variation of 0.3°), and centered 9.55° either side of fixation. They indicated in 2AFC which pair appeared separated by the shorter distance. In the adaptation trials, the stimuli were preceded by a 5-sec presentation of dense visual texture (visual adaptation), or by the participant rapidly tapping in mid-air with their dominant hand (motor adaptation) for 6 secs (in separate sessions). The effect of adaptation was measured by the shift of the point of subjective equality (PSE) before and after adaptation.<br>Results : Our data show that adaptation to self-produced fast hand movement induces a significant compression of the perceived spatial separation of the stimuli presented around the tapping location. The magnitude of motor adaptation aftereffects was robust, around 3%, a little smaller than that achieved by visual adaptation (around 10%). Importantly, distortions of perceived distance occurred only for stimuli presented around the adapted location, showing that the effect of both motor and visual adaptation is spatially selective.<br>Discussion : We report here that the estimated distance of two visual stimuli was compressed by repetitive motor action, similarly to adaptation to dense visual patterns. The spatial selectivity of the aftereffects suggests they do not derive from a decisional bias, but points to spatially selective mechanisms combining motor and visual information. To conclude, our results extend previous reports about the interaction of the perceptual and motor systems in the processing of time and numerosity to the processing of visual space. This is in line with the core idea of the ATOM theory of a shared representation for time, numerosity and space that optimizes the combination of perceptual information with motor planning and execution.<br>References : Walsh V Trends in cogn sci 7.11 (2003) 483-488 Hisakata R et al Curr Bio 26.14 (2016) 1911-1915 Anobile G et al J of Exp Psychology: General in press<br>Keywords : Perception & imagery; normal population; group study; adults; not relevant; behavioural, behavioural. 26/01/2020 31/01/2020 Petrizzo, I., Anobile, G., Burr, D. C., & Arrighi, R.

Bressanone

46.7177048 11.6572436 14 ChIJzQkqEmkFeEcR_Zac_Ls-KC8 Bressanone Trentino-Alto Adige BZ 39042 Italia IT https://www.pisavisionlab.org/2020/07/13/numerosity-adaptation-changes-in-sensory-processes-or-in-decision-making-2/ Mon, 13 Jul 2020 09:27:22 +0000 https://www.pisavisionlab.org/?p=2807 ["poster"] European Workshop on Cognitive Neuropsychology EWCN 2020 Bressanone Introduction : Humans and other animals can make rapid but approximate estimates of the numerosity of items in a scene, an ability often termed the number sense. Numerosity perception, like other senses, is susceptible to sensory adaptation: after an exposure to a patch containing many dots, subjects underestimate the numerosity of a second stimulus subsequently presented in the adapted region, with the opposite occurring for adaptation to small numerosities. Do these aftereffects arise from a change in the processing of sensory signals, or from a shift of criteria at the decisional stage? Methods : We addressed this question by investigating the effects of numerosity visual adaptation and motor adaptation in a 2AFC discrimination task on apparent numerosity (measured as point of subjective equality, or PSE), as well as on subjective confidence and reaction time. Results : Our results show that shifts in perceived numerosity after visual and motor adaptation are mirrored by shifts in both confidence and reaction time, with the maximum uncertainty and longest response time occurring at the point of subjective equality rather than at the point of physical equality. Discussion : Taken together these results are consistent with the hypothesis that numerosity adaptation aftereffects are perceptual in nature and not related to decisional processes. References : Morgan M. et al. Atten Percept Psychophys. (2012) 74(1):185-93. Abobile et al. eLife (2016) 5: e16161. Keywords : Numerical Cognition; normal population; group study; adults; not relevant; behavioural, behavioural. 26/01/2020 31/01/2020 Arrighi, R., Maldonado, P., Cicchini, G.M., Burr, D.

Bressanone

46.7177048 11.6572436 14 ChIJzQkqEmkFeEcR_Zac_Ls-KC8 Bressanone Trentino-Alto Adige BZ 39042 Italia IT https://www.pisavisionlab.org/2020/07/13/adaptation-to-hand-tapping-affects-directly-sensory-processing-of-numerosity/ Mon, 13 Jul 2020 09:30:55 +0000 https://www.pisavisionlab.org/?p=2813 ["digital poster"] Vision Science Society annual meeting, 20th annual meeting on-line event Several studies have demonstrated that numerosity perception is susceptible to adaptation: after exposure to high numerosities, participants underestimate the numerosity of subsequently patterns, and over-estimate after adaptation to low numerosities. We have recently shown that motor routines such as hand-tapping also affect numerosity estimates, and that the motor adaptation is confined to the tapping region, pointing to shared mechanisms encoding the quantity of both internally generated actions and externally generated events. However, it has been suggested that adaptation studies may reflect response biases rather than alteration of sensory processing. To disentangle the two possibilities, we studied visual and motor adaptation on numerosity perception (determined by the point of subjective equality in a 2AFC discrimination task), while also measuring participant confidence and reaction-times. If adaptation occurs at the sensory level, peaks in reaction-times and troughs in confidence should shift with adaptation to follow the new PSE, where the stimuli are most difficult to discriminate (Gallagher et al., 2019). On the other hand, if they result from response biases when confidence is low, the confidence (and also reaction-time) curves should remain centered at the unadapted PSE after adaptation. We replicate previous studies showing that both sensory and motor adaptation robustly distort numerosity estimates by 23% and 14% respectively. Importantly, in both cases, the shifts in perceived numerosity were almost perfectly mirrored by shifts in confidence and reaction-times, with the maximum uncertainty and longest response-times occurring at the point of subjective equality rather than at the point of physical equality. Taken together our results suggest that both forms of numerosity adaptation do not arise by decisional processes but directly act on the sensory representation of numerosity Acknowledgements: This research was funded by EU Horizon 2020 – ERC Advanced “Spatio-temporal mechanisms of generative perception”, Grant number 832813 – GenPercept and by the Italian Ministry of Education, University, and Research under the PRIN2017 programme (Grant number 2017XBJN4F— ‘EnvironMag’ ) 19/06/2020 24/06/2020 Arrighi, R., Maldonado, P., Cicchini, G.M., Burr, D. 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/horace-barlow-1921-2020/ Mon, 24 Aug 2020 15:45:32 +0000 https://www.pisavisionlab.org/?p=3105 Current Biology July 2020 Horace Barlow was one of the truly great neuroscientists of his time, in the Cambridge tradition of quantitative neurophysiology and psychophysics. His fundamental theoretical and empirical contributions to our understanding of brain function have inspired and influenced generations of neurophysiologists, psychologists and computational neuroscientists and are certain to endure for generations to come. David Burr; Simon Laughlin https://www.pisavisionlab.org/2020/08/24/horace-barlow-1921-2020/piis096098222031085x/https://doi.org/10.1016/j.cub.2020.07.060 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/2020/09/24/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/2020/09/24/fast-saccadic-eye-movements-in-humans-suggest-that-numerosity-perception-is-automatic-and-direct-2/ Thu, 24 Sep 2020 13:13:03 +0000 https://www.pisavisionlab.org/?p=3164 Proc. R. Soc. B 287: 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. Elisa Castaldi, David Burr, Marco Turi and Paola Binda https://doi.org/10.5061/dryad.7d7wm37s6 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/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/spontaneous-pupillary-oscillations-increase-during-mindfulness-meditation-2/ Fri, 09 Oct 2020 15:44:45 +0000 https://www.pisavisionlab.org/?p=3273 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 Pome' ; David C. Burr; Analisa Capuozzo; Paola Binda https://doi.org/10.5281/zenodo.3939009 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/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