RESUMEN
Human visual recognition is remarkably robust to chromatic changes. In this work, we provide a potential account of the roots of this resilience based on observations with 10 congenitally blind children who gained sight late in life. Several months or years following their sight-restoring surgeries, the removal of color cues markedly reduced their recognition performance, whereas age-matched normally sighted children showed no such decrement. This finding may be explained by the greater-than-neonatal maturity of the late-sighted children's color system at sight onset, inducing overly strong reliance on chromatic cues. Simulations with deep neural networks corroborate this hypothesis. These findings highlight the adaptive significance of typical developmental trajectories and provide guidelines for enhancing machine vision systems.
Asunto(s)
Ceguera , Percepción de Color , Visión de Colores , Reconocimiento Visual de Modelos , Niño , Femenino , Humanos , Masculino , Ceguera/rehabilitación , Ceguera/cirugía , Señales (Psicología) , Redes Neurales de la Computación , Adolescente , Adulto JovenRESUMEN
Deep convolutional neural networks (DCNNs) have demonstrated impressive robustness to recognize objects under transformations (e.g., blur or noise) when these transformations are included in the training set. A hypothesis to explain such robustness is that DCNNs develop invariant neural representations that remain unaltered when the image is transformed. However, to what extent this hypothesis holds true is an outstanding question, as robustness to transformations could be achieved with properties different from invariance; for example, parts of the network could be specialized to recognize either transformed or nontransformed images. This article investigates the conditions under which invariant neural representations emerge by leveraging that they facilitate robustness to transformations beyond the training distribution. Concretely, we analyze a training paradigm in which only some object categories are seen transformed during training and evaluate whether the DCNN is robust to transformations across categories not seen transformed. Our results with state-of-the-art DCNNs indicate that invariant neural representations do not always drive robustness to transformations, as networks show robustness for categories seen transformed during training even in the absence of invariant neural representations. Invariance emerges only as the number of transformed categories in the training set is increased. This phenomenon is much more prominent with local transformations such as blurring and high-pass filtering than geometric transformations such as rotation and thinning, which entail changes in the spatial arrangement of the object. Our results contribute to a better understanding of invariant neural representations in deep learning and the conditions under which it spontaneously emerges.
Asunto(s)
Redes Neurales de la Computación , Reconocimiento Visual de ModelosRESUMEN
In referential communication, gaze is often interpreted as a social cue that facilitates comprehension and enables word learning. Here we investigated the degree to which head turning facilitates gaze following. We presented participants with static pictures of a man looking at a target object in a first and third block of trials (pre- and post-intervention), while they saw short videos of the same man turning towards the target in the second block of trials (intervention). In Experiment 1, newly sighted individuals (treated for congenital cataracts; N = 8) benefited from the motion cues, both when comparing their initial performance with static gaze cues to their performance with dynamic head turning, and their performance with static cues before and after the videos. In Experiment 2, neurotypical school children (ages 5-10 years; N = 90) and adults (N = 30) also revealed improved performance with motion cues, although most participants had started to follow the static gaze cues before they saw the videos. Our results confirm that head turning is an effective social cue when interpreting new words, offering new insights for a pathways approach to development.
Asunto(s)
Señales (Psicología) , Fijación Ocular , Adulto , Atención , Niño , Preescolar , Comprensión , Humanos , Masculino , Aprendizaje VerbalRESUMEN
The long-standing nativist vs. empiricist debate asks a foundational question in epistemology - does our knowledge arise through experience or is it available innately? Studies that probe the sensitivity of newborns and patients recovering from congenital blindness are central in informing this dialogue. One of the most robust sensitivities our visual system possesses is to 'biological motion' - the movement patterns of humans and other vertebrates. Various biological motion perception skills (such as distinguishing between movement of human and non-human animals, or between upright and inverted human movement) become evident within the first months of life. The mechanisms of acquiring these capabilities, and specifically the contribution of visual experience to their development, are still under debate. We had the opportunity to directly examine the role of visual experience in biological motion perception, by testing what level of sensitivity is present immediately upon onset of sight following years of congenital visual deprivation. Two congenitally blind patients who underwent sight-restorative cataract-removal surgery late in life (at the ages of 7 and 20 years) were tested before and after sight restoration. The patients were shown displays of walking humans, pigeons, and cats, and asked to describe what they saw. Visual recognition of movement patterns emerged immediately upon eye-opening following surgery, when the patients spontaneously began to identify human, but not animal, biological motion. This recognition ability was evident contemporaneously for upright and inverted human displays. These findings suggest that visual recognition of human motion patterns may not critically depend on visual experience, as it was evident upon first exposure to un-obstructed sight in patients with very limited prior visual exposure, and furthermore, was not limited to the typical (upright) orientation of humans in real-life settings.
Asunto(s)
Percepción de Movimiento , Animales , Ceguera , Humanos , Recién Nacido , Movimiento (Física) , Trastornos de la Visión , Visión OcularRESUMEN
Towards the larger goal of understanding factors relevant for improving visuo-motor control, we investigated the role of visual feedback for modulating the effectiveness of a simple hand-eye training protocol. The regimen comprised a series of curve tracing tasks undertaken over a period of one week by neurologically healthy individuals with their non-dominant hands. Our three subject groups differed in the training they experienced: those who received 'Persistent' visual-feedback by seeing their hand and trace evolve in real-time superimposed upon the reference patterns, those who received 'Non-Persistent' visual-feedback seeing their hand movement but not the emerging trace, and a 'Control' group that underwent no training. Improvements in performance were evaluated along two dimensions-accuracy and steadiness, to assess visuo-motor and motor skills, respectively. We found that persistent feedback leads to a significantly greater improvement in accuracy than non-persistent feedback. Steadiness, on the other hand, benefits from training irrespective of the persistence of feedback. Our results not only demonstrate the feasibility of rapid visuo-motor learning in adulthood, but more specifically, the influence of visual veridicality and a critical role for dynamically emergent visual information.