Infant color perception: Insight into perceptual development

Preschoolers Represent Abstract Relations Predicated on Kind Membership

Recent work demonstrates that U.S. preschoolers can represent the abstract relational concepts same and different when these abstract relational concepts are predicated upon perceptual dimensions (e.g., size, shape, color). The current research investigates whether preschoolers (n = 192; predominantly White, upper middle class, U.S. convenience sample) can also represent the abstract relational concepts same and different when these abstract relational concepts are predicated upon abstract dimensions (e.g., kind membership). Experiment 1 shows that, at baseline, 4-year-olds fail at a relational match-to-sample (rMTS) task with familiar kinds. However, Experiment 2 shows that 4- and 5-year-olds, but not 3-year-olds, succeed at a rMTS task with familiar kinds when provided with training involving noun labels. Experiment 3 shows that 4- and 5-year-olds also succeed at a rMTS task with novel kinds when provided with training involving noun labels but not adjective labels, suggesting that noun labels but not adjective labels cue children's attention towards kind membership. Moreover, participants frequently provided explanations appealing to sameness and difference when justifying their responses. Taken together, these results suggest that, with training, preschoolers are capable of representing abstract relations predicated on abstract, as well as perceptual, dimensions.

Retinal ganglion cell circuits and glial interactions in humans and mice

Retinal ganglion cells (RGCs) are the brain's gateway for vision, and their degeneration underlies several blinding diseases. RGCs interact with other neuronal cell types, microglia, and astrocytes in the retina and in the brain. Much knowledge has been gained about RGCs and glia from mice and other model organisms, often with the assumption that certain aspects of their biology may be conserved in humans. However, RGCs vary considerably between species, which could affect how they interact with their neuronal and glial partners. This review details which RGC and glial features are conserved between mice, humans, and primates, and which differ. We also discuss experimental approaches for studying human and primate RGCs. These strategies will help to bridge the gap between rodent and human RGC studies and increase study translatability to guide future therapeutic strategies.

Impact of early visual experience on later usage of color cues

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.

Chromatic vision and structural assessment in primary congenital glaucoma

Primary congenital glaucoma is a rare disease that occurs in early birth and can lead to low vision. Evaluating affected children is challenging and there is a lack of studies regarding color vision in pediatric glaucoma patients. This cross-sectional study included 21 eyes of 13 children with primary congenital glaucoma who were assessed using the Farnsworth D-15 test to evaluate color vision discrimination and by spectral domain optical coherence tomography to measure retinal fiber layer thickness. Age, visual acuity, cup-to-disc ratio and spherical equivalent data were also collected. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were measured and compared based on color vision test performance. Four eyes (19%) failed the color vision test with diffuse dyschromatopsia patterns. Only age showed statistical significance in color vision test performance. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were similar between the color test outcomes dyschromatopsia and normal. While the color vision test could play a role in assessing children with primary congenital glaucoma, further studies are needed to correlate it with damage to retinal fiber layer thickness.

Visual and cognitive processes contribute to age-related improvements in visual selective attention

Children (N = 103, 4-9 years, 59 females, 84% White, c. 2019) completed visual processing, visual feature integration (color, luminance, motion), and visual search tasks. Contrast sensitivity and feature search improved with age similarly for luminance and color-defined targets. Incidental feature integration improved more with age for color-motion than luminance-motion. Individual differences in feature search (β  = .11) and incidental feature integration (β  = .06) mediated age-related changes in conjunction visual search, an index of visual selective attention. These findings suggest that visual selective attention is best conceptualized as a series of developmental trajectories, within an individual, that vary by an object's defining features. These data have implications for design of educational and interventional strategies intended to maximize attention for learning and memory.

Assessing perceptual chromatic equiluminance using a reflexive pupillary response

Equiluminant stimuli help assess the integrity of colour perception and the relationship of colour to other visual features. As a result of individual variation, it is necessary to calibrate experimental visual stimuli to suit each individual's unique equiluminant ratio. Most traditional methods rely on training observers to report their subjective equiluminance point. Such paradigms cannot easily be implemented on pre-verbal or non-verbal observers. Here, we present a novel Pupil Frequency-Tagging Method (PFTM) for detecting a participant's unique equiluminance point without verbal instruction and with minimal training. PFTM analyses reflexive pupil oscillations induced by slow (< 2 Hz) temporal alternations between coloured stimuli. Two equiluminant stimuli will induce a similar pupil dilation response regardless of colour; therefore, an observer's equiluminant point can be identified as the luminance ratio between two colours for which the oscillatory amplitude of the pupil at the tagged frequency is minimal. We compared pupillometry-based equiluminance ratios to those obtained with two established techniques in humans: minimum flicker and minimum motion. In addition, we estimated the equiluminance point in non-human primates, demonstrating that this new technique can be successfully employed in non-verbal subjects.

From water to land: Evolution of photoreceptor circuits for vision in air

When vertebrates first conquered the land, they encountered a visual world that was radically distinct from that of their aquatic ancestors. Fish exploit the strong wavelength-dependent interactions of light with water by differentially feeding the signals from up to 5 spectral photoreceptor types into distinct behavioural programmes. However, above the water the same spectral rules do not apply, and this called for an update to visual circuit strategies. Early tetrapods soon evolved the double cone, a still poorly understood pair of new photoreceptors that brought the "ancestral terrestrial" complement from 5 to 7. Subsequent nonmammalian lineages differentially adapted this highly parallelised retinal input strategy for their diverse visual ecologies. By contrast, mammals shed most ancestral photoreceptors and converged on an input strategy that is exceptionally general. In eutherian mammals including in humans, parallelisation emerges gradually as the visual signal traverses the layers of the retina and into the brain.

Consciousness in the cradle: on the emergence of infant experience

Although each of us was once a baby, infant consciousness remains mysterious and there is no received view about when, and in what form, consciousness first emerges. Some theorists defend a 'late-onset' view, suggesting that consciousness requires cognitive capacities which are unlikely to be in place before the child's first birthday at the very earliest. Other theorists defend an 'early-onset' account, suggesting that consciousness is likely to be in place at birth (or shortly after) and may even arise during the third trimester. Progress in this field has been difficult, not just because of the challenges associated with procuring the relevant behavioral and neural data, but also because of uncertainty about how best to study consciousness in the absence of the capacity for verbal report or intentional behavior. This review examines both the empirical and methodological progress in this field, arguing that recent research points in favor of early-onset accounts of the emergence of consciousness.

Color and newborn intensive care unit design: executive summary

Research on color in the design of healthcare settings is minimal. This paper provides an executive summary of a recent review on this topic, focusing on application to newborn intensive care units. The review focuses on the following question: Does the use of color in the design of the newborn intensive care units impact health outcomes in infants, families, and/or staff? We employed a structured review process, resulting in four studies involving the use of color in NICUs. The search was expanded to include general research on responses to color and studies in other healthcare settings. The literature clustered around preferences and psychobiological impact of color on infants and adults in NICUs, the interaction of color and light, and the impact of color on adults in general medical settings. Recommendations are made regarding the importance of modifiability and flexibility in the use of color in NICUs and colors that are associated with stress reduction and stimulation.

Color and NICU Design

PURPOSE

The appropriate use of color in healthcare settings has been a topic of interest for designers and researchers, and the need for evidence-based standards evident. The purpose of this article is to summarize recent research on color as applicable to neonatal intensive care units and to propose standards for color in these settings.

BACKGROUND

Research on this topic is limited due to difficulties associated with constructing research protocols, challenges in setting parameters for the independent variable (color), and the need to simultaneously address infants, families, and caregivers.

METHODS

For our literature review, the following research question was developed: Does the use of color in the design of the neonatal intensive care units (NICUs) impact health outcomes in newborn infants, families, and/or staff? Using Arksey and O'Malley's framework for conducting a structured literature review, we (1) identified the research question, (2) identified relevant studies, (3) selected studies, and (4) collated and summarized the results. Only four papers were found regarding NICUs, so the search was expanded to include related healthcare and authors reporting on best practice.

RESULTS

Overall, the primary research focused on behavioral or physiological outcomes including the role of wayfinding and art, the impact of lighting on color, and tools for evaluating the impact of color. Best practice recommendations sometimes reflected the primary research but occasionally provided contradictory advice.

CONCLUSIONS

Based on the reviewed literature, five topics are addressed: palette malleability; the use of the primary colors, blue, red, and yellow; and the relationship between light and color.

What determines the neural response to snakes in the infant brain? A systematic comparison of color and grayscale stimuli

Snakes and primates have coexisted for thousands of years. Given that snakes are the first of the major primate predators, natural selection may have favored primates whose snake detection abilities allowed for better defensive behavior. Aligning with this idea, we recently provided evidence for an inborn mechanism anchored in the human brain that promptly detects snakes, based on their characteristic visual features. What are the critical visual features driving human neural responses to snakes is an unresolved issue. While their prototypical curvilinear coiled shape seems of major importance, it remains possible that the brain responds to a blend of other visual features. Coloration, in particular, might be of major importance, as it has been shown to act as a powerful aposematic signal. Here, we specifically examine whether color impacts snake-specific responses in the naive, immature infant brain. For this purpose, we recorded the brain activity of 6-to 11-month-old infants using electroencephalography (EEG), while they watched sequences of color or grayscale animal pictures flickering at a periodic rate. We showed that glancing at colored and grayscale snakes generated specific neural responses in the occipital region of the brain. Color did not exert a major influence on the infant brain response but strongly increased the attention devoted to the visual streams. Remarkably, age predicted the strength of the snake-specific response. These results highlight that the expression of the brain-anchored reaction to coiled snakes bears on the refinement of the visual system.

The Development of Color Perception and Cognition

Color is a pervasive feature of our psychological experience, having a role in many aspects of human mind and behavior such as basic vision, scene perception, object recognition, aesthetics, and communication. Understanding how humans encode, perceive, talk about, and use color has been a major interdisciplinary effort. Here, we present the current state of knowledge on how color perception and cognition develop. We cover the development of various aspects of the psychological experience of color, ranging from low-level color vision to perceptual mechanisms such as color constancy to phenomena such as color naming and color preference. We also identify neurodiversity in the development of color perception and cognition and implications for clinical and educational contexts. We discuss the theoretical implications of the research for understanding mature color perception and cognition, for identifying the principles of perceptual and cognitive development, and for fostering a broader debate in the psychological sciences.