Philosophical thought experiments focusing on different kinds of visual spectrum manipulation and color inversion were initiated with John Locke’s hypothetical case of strawberries producing visual experiences of cucumbers (Locke 1689/1979). They still influence not only philosophical theories of color perception and color qualia inversion (e.g., Shoemaker 1982; Clark 1985; Levine 1988; Block 1990; Casati 1990; Broackes 1992; Hardin 1993; Tye 1993, 2000; Nida-Ruemelin 1993, 1996; Byrne & Hilbert 1997; Hurley 1998; Hilbert & Kalderon 2000; Cohen 2001; Myin 2001; McLaughlin 2003; Noë 2005; Churchland 2005; Macpherson 2005; Cohen & Matthen 2010; Burge 2010; O’Regan 2011), but also psychological research on the various ways in which our conscious experience can be modified and adapted to changes in visual input, such as space or luminance inversion (Heuer & Rapp 2011; Anstis 1992), or removing or enhancing colors (Belmore & Shevell 2011). However, a systematic interdisciplinary study on adaptation to an inverted or rotated color spectrum has been lacking until now.
The target article aims to lay the foundation for this, by presenting an experimental pilot study, along with some preliminary results and a brief discussion of its theoretical implications. Like many other pilot studies, it faces some limitations. These are: the small number of subjects tested; experimenters acting as test persons; and a complete lack of control conditions in the experimental protocol. The investigators are aware of these constraints and provide convincing reasons for the choices and strategy, e.g., their use of a novel, unpredictable, long-lasting, and inconvenient test protocol. Despite some difficulties relating to both empirical and conceptual aspects, the study demonstrates an original, interesting, and most importantly interdisciplinary approach to the topic of color perception and constancy, making an effort to combine psychological research with philosophical enactive theories.
The main objective of this commentary is to discuss what the sensorimotor account of perceptual consciousness could learn from investigations into phenomenal adaptation in atypical visual conditions such us color rotated spectrum and synesthesia. In the first section, after pinpointing the conceptual and methodological difficulties involved in defining and testing phenomenal adaptation in Grush et al.’s study, I shall deepen our understanding of phenomenal adaptation and analyze various possible readings of this phenomenon. Such readings depend on different interpretations of the contents that are admissible to perceptual consciousness (cf. Hawley & Macpherson 2011). In the second section, the relationship between the color rotation study and the enactive account of color vision is examined in order to demonstrate what consequences the sensorimotor theory may expect from results that confirm it in some respects, but not others. Finally, in the last two sections, I claim that the lessons for enactive theories of color perception may be expanded beyond the implications of the color rotation study. This is verified by looking at confirmatory and challenging cases provided by atypical perceptual conditions and color modifications such as synesthetic color experiences.