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Hysteresis as an implicit prior in tactile spatial decision making.

Thiel SD, Bitzer S, Nierhaus T, Kalberlah C, Preusser S, Neumann J, Nikulin VV, van der Meer E, Villringer A, Pleger B - PLoS ONE (2014)

Bottom Line: We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide 'same' rather than 'different' on successively presented pin distances.In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants' decisions than hysteresis.However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany ; Department of Psychology, Faculty of Mathematics and Natural Sciences II, Humboldt-University, Berlin, Germany.

ABSTRACT
Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide 'same' rather than 'different' on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants' decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence.

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Explained variance of pin distances and decision hysteresis.Bar graphs show the amount of explained variance of participants’ decisions for stimulus property (i.e., presented pin distance; dark gray bars) and decision hysteresis (light gray bars). The left panel shows explained variances across all five current and preceding pin distances; the right panel shows explained variances for each of the currently presented pin distances in combination with all other pin distances. Whiskers represent the standard error of the mean. Significant differences between variances explained by pin distances and hysteresis are denoted with one star for p<0.05, with two stars for p<0.01 and with three stars for p<0.001. See also Table 2.
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pone-0089802-g004: Explained variance of pin distances and decision hysteresis.Bar graphs show the amount of explained variance of participants’ decisions for stimulus property (i.e., presented pin distance; dark gray bars) and decision hysteresis (light gray bars). The left panel shows explained variances across all five current and preceding pin distances; the right panel shows explained variances for each of the currently presented pin distances in combination with all other pin distances. Whiskers represent the standard error of the mean. Significant differences between variances explained by pin distances and hysteresis are denoted with one star for p<0.05, with two stars for p<0.01 and with three stars for p<0.001. See also Table 2.

Mentions: Next, we directly compared the amount of variance explained by pin distances and decision hysteresis. Across all current pin distances the Wilcoxon signed rank test indicated that pin distances explained significantly more variance than hysteresis: Z = −3.78, p<0.001, see left panel of Figure 4. Post-hoc pairwise comparisons for each of the five current pin distances using Wilcoxon signed rank test yielded a significant difference for all current pin distances except for ‘threshold’ distances: ‘threshold−2’ (Z = −3.52, p<0.01), ‘threshold−1’ (Z = −3.22, p<0.01), ‘threshold+1’ (Z = −2.33, p<0.05), and ‘threshold+2’ (Z = −3.72, p<0.001) suggesting that the pin distance itself influenced participants’ decisions to a larger extend than hysteresis. At threshold, the Wilcoxon signed rank test yielded a trend for the inverse effect, which indicates that the variance of hysteresis had a more profound influence than the pin distances: Z = −1.85, p = 0.064, see Figure 5. Please note the large inter-individual differences in the magnitude of explained variance for both hysteresis and pin distances across participants (see right panel of Figure 4 and Table 2 for an overview).


Hysteresis as an implicit prior in tactile spatial decision making.

Thiel SD, Bitzer S, Nierhaus T, Kalberlah C, Preusser S, Neumann J, Nikulin VV, van der Meer E, Villringer A, Pleger B - PLoS ONE (2014)

Explained variance of pin distances and decision hysteresis.Bar graphs show the amount of explained variance of participants’ decisions for stimulus property (i.e., presented pin distance; dark gray bars) and decision hysteresis (light gray bars). The left panel shows explained variances across all five current and preceding pin distances; the right panel shows explained variances for each of the currently presented pin distances in combination with all other pin distances. Whiskers represent the standard error of the mean. Significant differences between variances explained by pin distances and hysteresis are denoted with one star for p<0.05, with two stars for p<0.01 and with three stars for p<0.001. See also Table 2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3935932&req=5

pone-0089802-g004: Explained variance of pin distances and decision hysteresis.Bar graphs show the amount of explained variance of participants’ decisions for stimulus property (i.e., presented pin distance; dark gray bars) and decision hysteresis (light gray bars). The left panel shows explained variances across all five current and preceding pin distances; the right panel shows explained variances for each of the currently presented pin distances in combination with all other pin distances. Whiskers represent the standard error of the mean. Significant differences between variances explained by pin distances and hysteresis are denoted with one star for p<0.05, with two stars for p<0.01 and with three stars for p<0.001. See also Table 2.
Mentions: Next, we directly compared the amount of variance explained by pin distances and decision hysteresis. Across all current pin distances the Wilcoxon signed rank test indicated that pin distances explained significantly more variance than hysteresis: Z = −3.78, p<0.001, see left panel of Figure 4. Post-hoc pairwise comparisons for each of the five current pin distances using Wilcoxon signed rank test yielded a significant difference for all current pin distances except for ‘threshold’ distances: ‘threshold−2’ (Z = −3.52, p<0.01), ‘threshold−1’ (Z = −3.22, p<0.01), ‘threshold+1’ (Z = −2.33, p<0.05), and ‘threshold+2’ (Z = −3.72, p<0.001) suggesting that the pin distance itself influenced participants’ decisions to a larger extend than hysteresis. At threshold, the Wilcoxon signed rank test yielded a trend for the inverse effect, which indicates that the variance of hysteresis had a more profound influence than the pin distances: Z = −1.85, p = 0.064, see Figure 5. Please note the large inter-individual differences in the magnitude of explained variance for both hysteresis and pin distances across participants (see right panel of Figure 4 and Table 2 for an overview).

Bottom Line: We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide 'same' rather than 'different' on successively presented pin distances.In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants' decisions than hysteresis.However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany ; Department of Psychology, Faculty of Mathematics and Natural Sciences II, Humboldt-University, Berlin, Germany.

ABSTRACT
Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide 'same' rather than 'different' on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants' decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence.

Show MeSH