Hypnotic color blindness and performance on the stroop test

Abstract

A suggestion for hypnotic color blindness was investigated by administering a reverse Stroop color-naming task. Prior to the suggestion for color blindness, participants learned associations between color names and shapes. Following the color blindness suggestion, participants were required to name the shapes when they appeared in colors that were either congruent or incongruent with the learned associations. The 18 high hypnotizable participants who passed the suggestion were slower to name (a) shapes in which the color name was incongruent with the color in which it was printed, (b) "unseen" rather than "seen" shapes, and (c) color-incongruent shapes that were printed in the color in which they were "color-blind." These patterns are discussed in terms of potential cognitive and social mechanisms that may mediate responses to hypnotic color blindness.

Hypnotic Suggestion and the Modulation of Stroop Interference

“…The current study is a "mirror image" of that by Kosslyn et al, 26 since in light of inconsistent data attempting to modulate the SIE through hypnotic manipulation of color perception, [27][28][29][30][31] we instead used a posthypnotic suggestion, which directed subjects not to read meaningful words (see "Methods" section). Based on previous research with hypnosis, we expected the highly suggestible subjects to be compliant with the suggestion made during the hypnotic experience following the hypnotic session, but not to remember the instruction.…”

“…24,25 The Stroop paradigm provides a promising way to investigate the modulation of attentional networks and top-down control via hypnosis and suggestion. 18 Although neuroimaging data reported by Kosslyn et al 26 show that a neural process as low-level as color perception was successfully affected by hypnotic suggestion, 26 other recent data suggest that hypnotic instruction for color blindness did not inhibit the SIE 27 (note earlier attempts at hypnotic suggestions for color blindness, [28][29][30][31] negative visual hallucination, and agnosia, 32 or comparable efforts in the auditory modality 33,34 ).…”

Hypnotic phenomena and altered states of consciousness: a multilevel framework of description and explanation

“…The Stroop Color and Word Test (Stroop, 1935), a behavioural test that is considered to be sensitive to frontal attentional functions, has, however, shown rather contradictory results in general. Some researchers have reported increased Stroop effects, while others found decreased effects in association with hypnotizability or hypnosis (see, for example, Sheehan, Donovan and MacLeod, 1988;Dixon, Brunet and Laurence, 1990;Dixon and Laurence 1992b;Kaiser, Barker, Haenschel, Baldeweg and Gruzelier, 1997;Nordby, Hugdahl, Jasiukaitis and Spiegel, 1999;Kallio, Revonsuo, Hämäläinen, Markela and Gruzelier, 2001;Mallard and Bryant 2001). An interesting recent finding showed that highly suggestible individuals were able to eliminate the Stroop interference effect following a posthypnotic suggestion designed to avoid attributing meaning to words (Raz, Shapiro, Fan and Posner, in press).…”

Elucidating unconscious processing with instrumental hypnosis

“…For example, it can alter perception of colors (Kosslyn et al, 2000; Mallard and Bryant, 2001; Spiegel, 2003; McGeown et al, 2009; Kallio and Koivisto, 2013; Koivisto et al, 2013), induce compelling experiences of grapheme-color synesthesia – a condition characterized by perceptual experiences of anomalous combinations of cross-modal sensations (Cohen Kadosh et al, 2009; however, see Anderson et al, 2014), and even temporarily abolish co-occurrences of secondary sensory experiences in synesthetes (Terhune et al, 2010). 1 Indicating the reliability and sustainability of these remarkable changes, hypnotically induced alteration of color perception correlates with corresponding modifications in neural response (Kosslyn et al, 2000; McGeown et al, 2012).…”