Visual experience shapes the Bouba‑Kiki effect and the size‑weight illusion upon sight restoration from congenital blindness

The Bouba-Kiki effect is the systematic mapping between round/spiky shapes and speech sounds (“Bouba”/“Kiki”). In the size-weight illusion, participants judge the smaller of two equallyweighted objects as being heavier. Here we investigated the contribution of visual experience to the development of these phenomena. We compared three groups: early blind individuals (no visual experience), individuals treated for congenital cataracts years after birth (late visual experience), and typically sighted controls (visual experience from birth). We found that, in cataract-treated participants (tested visually/visuo-haptically), both phenomena are absent shortly after sight onset, just like in blind individuals (tested haptically). However, they emerge within months following surgery, becoming statistically indistinguishable from the sighted controls. This suggests a pivotal role of visual experience and refutes the existence of an early sensitive period: A short period of experience, even when gained only years after birth, is sufficient for participants to visually pick-up regularities in the environment, contributing to the development of these phenomena

Hearing in slow-motion: Humans underestimate the speed of moving sounds.

Senna I, Parise C, Ernst MO. Hearing in slow-motion: Humans underestimate the speed of moving sounds. Scientific Reports. 2015;5(1): 14054.Perception can often be described as a statistically optimal inference process whereby noisy and incomplete sensory evidence is combined with prior knowledge about natural scene statistics. Previous evidence has shown that humans tend to underestimate the speed of unreliable moving visual stimuli. This finding has been interpreted in terms of a Bayesian prior favoring low speed, given that in natural visual scenes objects are mostly stationary or slowly-moving. Here we investigated whether an analogous tendency to underestimate speed also occurs in audition: even if the statistics of the visual environment seem to favor low speed, the statistics of the stimuli reaching the individual senses may differ across modalities, hence potentially leading to different priors. Here we observed a systematic bias for underestimating the speed of unreliable moving sounds. This finding suggests the existence of a slow-motion prior in audition, analogous to the one previously found in vision. The nervous system might encode the overall statistics of the world, rather than the specific properties of the signals reaching the individual senses

Policy Recommendations for Supporting Supply Chains with Horizontal Actions

This chapter aims to identify the supply chain (SC) issues that can be considered “horizontal”, as they are cross–sectorial and faced by most companies operating both in production and distribution sectors, and to propose a set of policy recommendations that can support public and private organisations to promote and foster innovation and competitiveness of future European SCs. The definition of the Key Horizontal Issues (KHI) is the basis for developing 12 policy recommendations regarding infrastructure requirements, technological and organisational improvements and regulatory developments needed to set the stage for the European SCs for the future. Specifically, the policy recommendations entail assuring appropriate standards and legislation for European SCs; educating and training professionals for the future SCs; drafting of international agreements aiming at future European SCs; supporting and fostering incentives and funding schemes; promoting reference bodies for European SCs; and establishing infrastructure for fostering of future European SCs

Development of local-global preference in vision and haptics

We aimed to advance our understanding of local-global preference by exploring its developmental path within and across sensory modalities: vision and haptics. Neurotypical individuals from six years of age through adulthood completed a similarity judgement task with hierarchical haptic or visual stimuli made of local elements (squares or triangles) forming a global shape (a square or a triangle). Participants chose which of two probes was more similar to a target: the one sharing the global shape (but different local shapes) or the one with the same local shapes (but different global shape). Across trials, we independently varied the size of the local elements and that of the global configuration—the latter was varied by manipulating local element density while keeping their numerosity constant.We found that the size of local elements (but not global size) modulates the effects of age and modality. For stimuli with smaller local elements, the proportion of global responses increased with age and was similar for visual and haptic stimuli. However, for stimuli made of our largest local elements, the global preference was reduced or absent, particularly in haptics, regardless of age. These results suggest that vision and haptics progressively converge toward similar global preference with age, but residual differences across modalities and across individuals may be observed, depending on the characteristics of the stimuli

Recalibrating vision-for-action requires years after sight restoration from congenital cataracts

Being able to perform adept goal-directed actions requires predictive, feed-forward control, including a mapping between the visually estimated target locations and the motor commands reaching for them. When the mapping is perturbed, e.g., due to muscle fatigue or optical distortions, we are quickly able to recalibrate the sensorimotor system to update this mapping. Here we investigated whether early visual and visuomotor experience is essential for developing sensorimotor recalibration. To this end, we assessed young individuals deprived from pattern vision due to dense congenital bilateral cataracts, who were surgically treated for sight restoration only years after birth. We compared their recalibration performance to such distortion to that of age-matched sighted controls. Their sensorimotor recalibration performance was impaired right after surgery. This finding cannot be explained by their still lower visual acuity alone, since blurring vision in controls to a matching degree did not lead to comparable behavior. Nevertheless, the recalibration ability of cataract-treated participants gradually improved with time after surgery. Thus, the lack of early pattern vision affects visuomotor recalibration. However, this ability is not lost but slowly develops after sight restoration, highlighting the importance of sensorimotor experience gained late in life

The Impact of Latency on Perceptual Judgments and Motor Performance in Closed-loop Interaction in Virtual Reality

Waltemate T, Senna I, Hülsmann F, et al. The Impact of Latency on Perceptual Judgments and Motor Performance in Closed-loop Interaction in Virtual Reality. In: Proceedings of ACM Symposium on Virtual Reality Software and Technology. New York: ACM; 2016: 27-35

Seeing touches early in life

Addabbo M, Longhi E, Bolognini N, et al. Seeing touches early in life. PLoS ONE. 2015;10(9): e0134549

Altered visual feedback modulates cortical excitability in a mirror-box-like paradigm

Senna I, Russo C, Parise C, Ferrario I, Bolognini N. Altered visual feedback modulates cortical excitability in a mirror-box-like paradigm. Experimental Brain Research. 2015;233(6):1921-1929

Analogous motion illusion in audition and vision

Senna I, Parise C, Ernst MO. Analogous motion illusion in audition and vision. Presented at the the 15th International Multisensory Research Forum IMRF, Amsterdam, The Netherland

Modulation frequency as a cue for auditory speed perception

Senna I, Parise C, Ernst MO. Modulation frequency as a cue for auditory speed perception. Proceedings of the Royal Society B: Biological Sciences. 2017;284(1858): 20170673