Arias Diana Jimena, Saint-Amour Dave
Department of Psychology, Université du Québec à Montréal, Montreal, H2X 3P2, Canada.
Cognitive Neurosciences Research Center, Université du Québec à Montréal, Montreal, H2X 3P2, Canada.
Sci Rep. 2021 Apr 7;11(1):7566. doi: 10.1038/s41598-021-87223-w.
Grapheme-colour synesthesia occurs when letters or numbers elicit an abnormal colour sensation (e.g., printed black letters are perceived as coloured). This phenomenon is typically reported following explicit presentation of graphemes. Very few studies have investigated colour sensations in synesthesia in the absence of visual awareness. We took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthetic alphanumeric and non-synesthetic stimuli were presented to 21 participants (11 synesthetes) in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked by a sudden presentation of visual noise in the other eye (flash suppression). The time for an image to be re-perceived following the onset of the suppressive noise was calculated. Trials where there was no flash suppression performed but instead mimicked the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. No difference was found between the groups in the flash suppression condition. Our findings suggest that synesthesia is associated with enhanced perception for overt recognition, but does not provide an advantage in recovering from a perceptual suppression. Further studies are needed to investigate synesthesia in relation to visual awareness.
当字母或数字引发异常的颜色感觉（例如，印刷的黑色字母被感知为有颜色）时，就会出现字形-颜色联觉。这种现象通常在明确呈现字形后被报告。很少有研究在没有视觉意识的情况下调查联觉中的颜色感觉。我们利用双眼分视闪光抑制范式暂时使呈现给一只眼睛的刺激变得不可见。在无色和有色实验条件下，向21名参与者（11名联觉者）呈现联觉字母数字和非联觉刺激。测试刺激首先显示给一只眼睛，然后通过在另一只眼睛中突然呈现视觉噪声（闪光抑制）进行掩蔽。计算在抑制性噪声开始后重新感知图像的时间。还测试了没有进行闪光抑制但模仿闪光的感知抑制的试验。结果表明，在没有闪光抑制的情况下，联觉者的目标检测明显优于对照组。在闪光抑制条件下，两组之间没有发现差异。我们的研究结果表明，联觉与增强的显性识别感知相关，但在从感知抑制中恢复方面没有优势。需要进一步的研究来调查与视觉意识相关的联觉。
