3D shape-from-shading relies on a light source prior that does not change with age

Abstract

The light-from-above prior enables observers to infer an object's three-dimensional shapefrom-shading information. Young, Western adults implicitly assume the light source is placed not only above, but also to the left of, the observer. Previous evidence reached conflicting conclusions regarding the development of the assumed light source direction. In the present study, we measured the light source prior cross-sectionally in children aged 5-11 years, using an explicit shape judgement task. The light-from-above prior, and the left bias, were present as soon as children became sensitive to shading information, regardless of their age. Global processing preference was not related to the ability to perform the task. Similarly, scanning habits, as measured by reading proficiency and starting position in a cancellation task, were not related to the magnitude of the left bias. Children's ability to report shape-from-shading judgements increased with age, but age did not affect the direction of light priors. Thus, we concluded that the development of the light-from-above prior and leftward bias do not require an extended maturation period, but rather the direction of the light-source priors may be developmentally stable once measurable.

Natural Contrast Statistics Facilitate Human Face Categorization

“…It is unclear whether this shift in the emergence of the general visual response is due to a differential activation of the center-surround receptive fields in the retina or the lateral geniculate nuclei (Meister and Berry, 1999), and/or whether it is due to contrast negation hindering general, low-level visual processing in the cortex (e.g. perception of brightness: Yang and Purves, 2004;Pickard-Jones et al, 2020;orientation;Girshick et al, 2011;apparent contrast: Bex and Makous, 2002;Haun and Peli, 2013). Hence, shading, i.e.…”

“…Contrast negation induced a moderate shift in the onset of the general visual response toward higher contrast values, but did not affect the level of contrast required to elicit an optimal general visual response or its overall magnitude. It is unclear whether this shift in the emergence of the general visual response is because of a differential activation of the center-surround receptive fields in the retina or the lateral geniculate nuclei ( Meister and Berry, 1999 ), and/or whether it is because of contrast negation hindering general, low-level visual processing in the cortex (e.g., perception of brightness, Yang and Purves, 2004 ; Pickard-Jones et al, 2020 ; orientation, Girshick et al, 2011 ; apparent contrast, Bex and Makous, 2002 ; Haun and Peli, 2013 ). Hence, shading, i.e., the pattern of luminance across a surface, is informative of the structural properties of many things around us, not just faces.…”

Scanning laser ophthalmoscopy retroillumination: applications and illusions

“…Shading and border structure help an observer identify a three-dimensional object's shape but shape-fromshading percepts can produce false illusions of depth in two-dimensional objects [15,16,22]. Visual perception integrates sensory data with sensory biases acquired from prior experiences ("priors"), including the expectation that the shading of natural objects is caused by a single light source [15][16][17][18][19][20][21][22]. Shape-from-shading pseudo3D illusions have also been observed previously in scanning electron microscopy [58] and retinal differential interference contrast microscopy images.…”

“…It also facilitates identification of large-area chorioretinal irregularities not readily displayed in other en face retinal imaging modalities [11][12][13][14]. Shaded boundaries create the perception of elevation or depression in imaged structures [15][16][17][18][19][20][21][22], a characteristic of retroillumination but not standard reflectance SLO imaging. This perception is an illusion rather than an objective three-dimensional representation of chorioretinal anatomy as provided by optical coherence tomography (OCT).…”

Classification images for aerial images capture visual expertise for binocular disparity and a prior for lighting from above

“…This is also a conservative estimate. In a study by Pickard-Jones, D'Avossa, and Sapir (2020) using the honeycomb stimulus, all 58 children between the ages of 7 and 11 years showed a bias to lighting from above. In addition, using shaded bubbles, Sun and Perona (1998) found that 12 adults (evenly split for handedness) all had biases to lighting from above.…”