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From Perception to Metacognition: Auditory and Olfactory Functions in Early Blind, Late Blind, and Sighted Individuals

View Article: PubMed Central - PubMed

ABSTRACT

Although evidence is mixed, studies have shown that blind individuals perform better than sighted at specific auditory, tactile, and chemosensory tasks. However, few studies have assessed blind and sighted individuals across different sensory modalities in the same study. We tested early blind (n = 15), late blind (n = 15), and sighted (n = 30) participants with analogous olfactory and auditory tests in absolute threshold, discrimination, identification, episodic recognition, and metacognitive ability. Although the multivariate analysis of variance (MANOVA) showed no overall effect of blindness and no interaction with modality, follow-up between-group contrasts indicated a blind-over-sighted advantage in auditory episodic recognition, that was most pronounced in early blind individuals. In contrast to the auditory modality, there was no empirical support for compensatory effects in any of the olfactory tasks. There was no conclusive evidence for group differences in metacognitive ability to predict episodic recognition performance. Taken together, the results showed no evidence of an overall superior performance in blind relative sighted individuals across olfactory and auditory functions, although early blind individuals exceled in episodic auditory recognition memory. This observation may be related to an experience-induced increase in auditory attentional capacity.

No MeSH data available.


(A–H) Boxplots of absolute odor threshold (A), odor discrimination (B), odor identification of high familiar stimuli (C), episodic odor recognition (d') (D), absolute auditory threshold (E), sound discrimination (F), sound identification of high familiar stimuli (G), and episodic sound recognition (d') (H). Boxplots are displayed separately for early blind (dark gray boxes), late blind (light gray boxes), and sighted (white boxes) participants. The boxes indicate the 25th, 50th (median), and 75th percentiles of the distribution (lower, middle, and upper horizontal lines of the box). The upper hinges indicate the maximum value of the variable located within a distance of 1.5 times the inter-quartile range above the 75th percentile. The lower hinges indicate the corresponding distance to the 25th percentile value. Circles indicate values outside these hinges (outliers). The means and 95% confidence intervals (dots and error bars in blue) are superimposed on the boxplots.
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Figure 1: (A–H) Boxplots of absolute odor threshold (A), odor discrimination (B), odor identification of high familiar stimuli (C), episodic odor recognition (d') (D), absolute auditory threshold (E), sound discrimination (F), sound identification of high familiar stimuli (G), and episodic sound recognition (d') (H). Boxplots are displayed separately for early blind (dark gray boxes), late blind (light gray boxes), and sighted (white boxes) participants. The boxes indicate the 25th, 50th (median), and 75th percentiles of the distribution (lower, middle, and upper horizontal lines of the box). The upper hinges indicate the maximum value of the variable located within a distance of 1.5 times the inter-quartile range above the 75th percentile. The lower hinges indicate the corresponding distance to the 25th percentile value. Circles indicate values outside these hinges (outliers). The means and 95% confidence intervals (dots and error bars in blue) are superimposed on the boxplots.

Mentions: The MANOVA on the olfactory and auditory tests (threshold, discrimination, identification, and episodic recognition) showed no significant effect of group [Wilk's λ = 0.82, F(8, 108) = 1.37, p = 0.22], modality [Wilk's λ = 0.98, F(4, 54) = 0.30, p = 0.87], or interaction between group and modality [Wilk's λ = 0.79, F(8, 108) = 1.71, p = 0.10]. However, visual inspection of group data (Figure 1) did not suggest a random pattern of group differences: for some tasks, blind performed better than sighted, and early blind performed better than late blind, consistent with what we would expect from previous research. We therefore proceeded by calculating between-group contrasts for each task using independent-samples t-tests (to control for multiple comparison, the p-values reported below should be evaluated at a Bonferroni corrected alpha = 0.05/24 = 0.002).


From Perception to Metacognition: Auditory and Olfactory Functions in Early Blind, Late Blind, and Sighted Individuals
(A–H) Boxplots of absolute odor threshold (A), odor discrimination (B), odor identification of high familiar stimuli (C), episodic odor recognition (d') (D), absolute auditory threshold (E), sound discrimination (F), sound identification of high familiar stimuli (G), and episodic sound recognition (d') (H). Boxplots are displayed separately for early blind (dark gray boxes), late blind (light gray boxes), and sighted (white boxes) participants. The boxes indicate the 25th, 50th (median), and 75th percentiles of the distribution (lower, middle, and upper horizontal lines of the box). The upper hinges indicate the maximum value of the variable located within a distance of 1.5 times the inter-quartile range above the 75th percentile. The lower hinges indicate the corresponding distance to the 25th percentile value. Circles indicate values outside these hinges (outliers). The means and 95% confidence intervals (dots and error bars in blue) are superimposed on the boxplots.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037222&req=5

Figure 1: (A–H) Boxplots of absolute odor threshold (A), odor discrimination (B), odor identification of high familiar stimuli (C), episodic odor recognition (d') (D), absolute auditory threshold (E), sound discrimination (F), sound identification of high familiar stimuli (G), and episodic sound recognition (d') (H). Boxplots are displayed separately for early blind (dark gray boxes), late blind (light gray boxes), and sighted (white boxes) participants. The boxes indicate the 25th, 50th (median), and 75th percentiles of the distribution (lower, middle, and upper horizontal lines of the box). The upper hinges indicate the maximum value of the variable located within a distance of 1.5 times the inter-quartile range above the 75th percentile. The lower hinges indicate the corresponding distance to the 25th percentile value. Circles indicate values outside these hinges (outliers). The means and 95% confidence intervals (dots and error bars in blue) are superimposed on the boxplots.
Mentions: The MANOVA on the olfactory and auditory tests (threshold, discrimination, identification, and episodic recognition) showed no significant effect of group [Wilk's λ = 0.82, F(8, 108) = 1.37, p = 0.22], modality [Wilk's λ = 0.98, F(4, 54) = 0.30, p = 0.87], or interaction between group and modality [Wilk's λ = 0.79, F(8, 108) = 1.71, p = 0.10]. However, visual inspection of group data (Figure 1) did not suggest a random pattern of group differences: for some tasks, blind performed better than sighted, and early blind performed better than late blind, consistent with what we would expect from previous research. We therefore proceeded by calculating between-group contrasts for each task using independent-samples t-tests (to control for multiple comparison, the p-values reported below should be evaluated at a Bonferroni corrected alpha = 0.05/24 = 0.002).

View Article: PubMed Central - PubMed

ABSTRACT

Although evidence is mixed, studies have shown that blind individuals perform better than sighted at specific auditory, tactile, and chemosensory tasks. However, few studies have assessed blind and sighted individuals across different sensory modalities in the same study. We tested early blind (n = 15), late blind (n = 15), and sighted (n = 30) participants with analogous olfactory and auditory tests in absolute threshold, discrimination, identification, episodic recognition, and metacognitive ability. Although the multivariate analysis of variance (MANOVA) showed no overall effect of blindness and no interaction with modality, follow-up between-group contrasts indicated a blind-over-sighted advantage in auditory episodic recognition, that was most pronounced in early blind individuals. In contrast to the auditory modality, there was no empirical support for compensatory effects in any of the olfactory tasks. There was no conclusive evidence for group differences in metacognitive ability to predict episodic recognition performance. Taken together, the results showed no evidence of an overall superior performance in blind relative sighted individuals across olfactory and auditory functions, although early blind individuals exceled in episodic auditory recognition memory. This observation may be related to an experience-induced increase in auditory attentional capacity.

No MeSH data available.