What can pictorial artifacts teach us about light and lightness?1

Zavagno, Daniele; Daneyko, Olga; Sakurai, Kazuo

doi:10.1111/j.1468-5884.2011.00488.x

Cited by 14 publications

(12 citation statements)

References 36 publications

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“…Although this study may appear to support the idea that an internal representation of illumination is relevant to lightness perception (i.e., the albedo hypothesis), a long discussion on whether illumination affects lightness perception must be noted (Agostini & Galmonte, 2002; Gilchrist, 2006; Schirillo, 2013; Zavagno & Daneyko, 2012; Zavagno, Daneyko, & Sakurai, 2011). Studies have argued that complex processing that collects illumination cues and subsequently constructs representations does not play a role in lightness processing (e.g., Gilchrist, 2006, 2018).…”

Section: Discussionmentioning

confidence: 55%

An Upward-Facing Surface Appears Darker: The Role Played by the Light-From-Above Assumption in Lightness Perception

Kobayashi

Morikawa

2019

Perception

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The human visual system can extract information on surface reflectance (lightness) from light intensity; this, however, confounds information on reflectance and illumination. We hypothesized that the visual system, to solve this lightness problem, utilizes the internally held prior assumption that illumination falls from above. Experiment 1 showed that an upward-facing surface is perceived to be darker than a downward-facing surface, proving our hypothesis. Experiment 2 showed the same results in the absence of explicit illumination cues. The effect of the light-from-left prior assumption was not observed in Experiment 3. The upward- and downward-facing surface stimuli in Experiments 1 and 2 showed no difference in a two-dimensional configuration or three-dimensional structure, and the participants’ perceived lightness appeared to be affected by the observers’ prior assumption that illumination is always from above. Other studies have not accounted for this illusory effect, and this study’s finding provides additional insights into the study of lightness perception.

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Section: Discussionmentioning

confidence: 55%

An Upward-Facing Surface Appears Darker: The Role Played by the Light-From-Above Assumption in Lightness Perception

Kobayashi

Morikawa

2019

Perception

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“…Distinguishing between lightness and brightness could resolve this contradiction because lightness refers to perceived reflectance, whereas brightness refers to perceived luminance or intensity of light (Schirillo, Reeves, & Arend, 1990;Zavagno, Daneyko, & Sakurai, 2011). Although Tamura et al (2016) did not seem to define lightness and brightness clearly in their experiments, probably their participants judged brightness.…”

Section: Resultsmentioning

confidence: 89%

“Glowing Gray” Does Exist: Luminance Gradients’ Influence on Whiteness Perception

2018

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Studies on brightness and lightness that employed luminance gradients (i.e., glare stimuli) have suggested that we can perceive luminosity even when the brightness target is darker than white. Although such studies had great impact on research in luminosity perception, whether the whiteness threshold in glare stimuli was lower or higher than the luminosity threshold remained unclear. This study indicated that it is higher than the luminosity threshold, confirming the existence of glowing gray. Moreover, we measured the luminance gradients' effect on whiteness perception but found no significant effect. Discrepancy in the degree of gradients' effect on perceived luminosity and perceived white suggests that different mechanisms underlie luminosity (brightness) perception and whiteness (lightness) perception.

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“…The Gestalt and the Ecological approaches share a common indifference towards the notion of veridicality, but for different reasons: if for the Ecological approach such concept is unnecessary , for the Gestalt approach it is irrelevant , given that there is no way to establish whether a percept is veridical with respect to the distal source of stimulation, as knowledge of such source comes from the percept itself, or is mediated by the use of some instrumentation, which however cannot tell what is more veridical. Moreover physical properties of a distal stimulus are only rough correlates of what is perceived (Zavagno et al, 2011a , b ). For instance, the luminance of an achromatic surface is the physical correlate of lightness (achromatic surface color), which however, does not correlate with the luminance of the physical surface: a sheet of paper with reflectance 70% may appear light gray even if its luminance changes dramatically, because lightness is a contextual experience, functional to the characteristics of the scene in relation to the perceiver.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Mishaps, errors, and cognitive experiences: on the conceptualization of perceptual illusions

Zavagno

Daneyko

Actis-Grosso

2015

Front. Hum. Neurosci.

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Although a visual illusion is often viewed as an amusing trick, for the vision scientist it is a question that demands an answer, which leads to even more questioning. All researchers hold their own chain of questions, the links of which depend on the very theory they adhere to. Perceptual theories are devoted to answering questions concerning sensation and perception, but in doing so they shape concepts such as reality and representation, which necessarily affect the concept of illusion. Here we consider the macroscopic aspects of such concepts in vision sciences from three classic viewpoints—Ecological, Cognitive, Gestalt approaches—as we see this a starting point to understand in which terms illusions can become a tool in the hand of the neuroscientist. In fact, illusions can be effective tools in studying the brain in reference to perception and also to cognition in a much broader sense. A theoretical debate is, however, mandatory, in particular with regards to concepts such as veridicality and representation. Whether a perceptual outcome is considered as veridical or illusory (and, consequently, whether a class of phenomena should be classified as perceptual illusions or not) depends on the meaning of such concepts.

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What can pictorial artifacts teach us about light and lightness?1

Cited by 14 publications

References 36 publications

An Upward-Facing Surface Appears Darker: The Role Played by the Light-From-Above Assumption in Lightness Perception

An Upward-Facing Surface Appears Darker: The Role Played by the Light-From-Above Assumption in Lightness Perception

“Glowing Gray” Does Exist: Luminance Gradients’ Influence on Whiteness Perception

Mishaps, errors, and cognitive experiences: on the conceptualization of perceptual illusions

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