Language regions of brain are operative in color perception

Abstract

The effect of language on the categorical perception of color is stronger for stimuli in the right visual field (RVF) than in the left visual field, but the neural correlates of the behavioral RVF advantage are unknown. Here we present brain activation maps revealing how language is differentially engaged in the discrimination of colored stimuli presented in either visual hemifield. In a rapid, event-related functional MRI study, we measured subjects' brain activity while they performed a visual search task. Compared with colors from the same lexical category, discrimination of colors from different linguistic categories provoked stronger and faster responses in the left hemisphere language regions, particularly when the colors were presented in the RVF. In addition, activation of visual areas 2/3, responsible for color perception, was much stronger for RVF stimuli from different linguistic categories than for stimuli from the same linguistic category. Notably, the enhanced activity of visual areas 2/3 coincided with the enhanced activity of the left posterior temporoparietal language region, suggesting that this language region may serve as a top-down control source that modulates the activation of the visual cortex. These findings shed light on the brain mechanisms that underlie the hemifielddependent effect of language on visual perception. functional magnetic resonance imaging (fMRI) ͉ lateralization A typically viewed scene permits multiple visual parses, some of which can be readily mapped onto linguistic terms, whereas others cannot. Does linguistic information play a role in visual perception? For more than half a century, this question has provoked controversy. According to the hypothesis proposed by Benjamin Lee Whorf (1), by filtering perception, language affects our apprehension of the world. This hypothesis has received conflicting evidence (2-21); a recent review favors the view that linguistic categories filter some, but not all, perceptual inputs and that perceptual factors influence, but do not exclusively determine, linguistic categories of color (22).Recent neuropsychological investigations examining visual field asymmetries in the categorical perception (CP) of colors have provided a new perspective on Whorfian effects. In a study using a visual search task (7), adult English speakers were required to detect a single target color among 11 identical distractor colors. Response times for finding the target were faster when target and distractors were from 2 different lexical categories (e.g., a green target among blue distractors) than when target and distractors were from the same lexical category (e.g., a particular green among distractors of a different green), but only when the target was exposed in the right visual field (RVF). Because the RVF projects to the left cerebral hemisphere, the dominant hemisphere for language in most adults, and because the effect was eliminated by a concurrent task occupying verbal processing resources but not by an equally difficult task occupying nonverbal r...

Cross-species Assessment of the Linguistic Origins of Color Categories.

“…The categorical response was early in the ERP trace but even earlier (i.e., P1) components have been recently claimed for color categories (Holmes et al, 2009;Thierry et al, 2009). Given the activation of language areas in color judgments, these recent ERP studies suggesting categorical activity in (extra)striate cortical areas would appear to require a rapid activation of feedback networks during color processing (Siok et al, 2009). Presumably, these feedback loops are disrupted by concurrent verbal activity (Gilbert et al, 2006; and hence color perception is no longer categorical Given such clear implication for language in human color CP, we examined the cross-species research that might lead one to believe that non-humans also demonstrate CP for colors.…”

“…Despite preserved color vision, in addition to a retained ability to categorize other stimuli, patients in these studies failed to understand the meaning of color terms, and failed to sort colors, suggesting that colors do not automatically form categories once color terms have been lost. Further, neuroimaging studies showed left hemisphere activations in known language areas during color comparison tasks (e.g., Siok et al , 2009;Tan et al, 2008;Thierry et al, 2009). For example, in Siok et al (2009) it was only categorical color decisions in a visual search task that were accompanied by activation in language areas.…”

“…Further, neuroimaging studies showed left hemisphere activations in known language areas during color comparison tasks (e.g., Siok et al , 2009;Tan et al, 2008;Thierry et al, 2009). For example, in Siok et al (2009) it was only categorical color decisions in a visual search task that were accompanied by activation in language areas.…”

“…However, if language is the critical factor, there is a non-obvious consequence. One ought to find cross-species differences in the apparently non-verbal task of color categorization because recent cross-lingual and neuroimaging investigations have shown a linguistic component to its performance (Davidoff, 2001;Davidoff, Davies & Roberson, 1999;Roberson, Davidoff, Davies & Shapiro, 2004Roberson, Davies & Davidoff, 2000;Siok, Kay, Wang, Chan, Chen, Luke & Tan, 2009;Tan, Chan, Kay, Khong, Yip & Luke, 2008;Thierry, Athanasopoulos, Wiggett, Dering & Kuipers, 2009;Winawer, Witthoft, Frank, Wu & Boroditsky, 2007; see also Kay & Kempton, 1984). In one of the neuroimaging studies, Tan et al (2008) even showed activation of language areas of the brain for the simple, apparently purely visual, task of judging whether two colors were the same or different.…”

Is the Lateralized Categorical Perception of Color a Situational Effect of Language on Color Perception?

“…In the past decade, many studies have found that the effect of language on color perception is lateralized to the left hemisphere (Franklin, Drivonikou, Bevis, et al, 2008;Franklin, Drivonikou, Clifford, et al, 2008;Gilbert, Regier, Kay, & Ivry, 2006;Liu et al, 2010;Mo, Xu, Kay, & Tan, 2011;Siok et al, 2009;Tan et al, 2008;Thierry, Athanasopoulos, Wiggett, Dering, & Kuipers, 2009). For instance, Gilbert et al (2006) chose four graduated colors as experimental material, as shown in Fig.…”