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Introspecting on the Timing of One's Actions in a Visuo-Motor Synchronization Task.

Gzorea A, Rider D - Front Psychol (2011)

Bottom Line: By means of a new visuo-motor synchronization paradigm we test the frequently made proposition that one's feeling of having voluntarily made a decision to act is in fact postdictively established contingent on the outcome of his action rather than on its aim.Instead, response time distributions were bimodal for the shortest (0 ms) and longest (500 ms) SIs and widely spread for intermediate SIs.To all three questions asked, subjects' responses strongly correlated with SI itself (r = 0.62-0.76) and barely with their actual response times (r = 0.03-0.42).

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes and CNRS Paris, France.

ABSTRACT
By means of a new visuo-motor synchronization paradigm we test the frequently made proposition that one's feeling of having voluntarily made a decision to act is in fact postdictively established contingent on the outcome of his action rather than on its aim. Subjects had to (1) synchronize a key-press with the end of a random synchronization interval (SI) shorter or longer than their reaction time (RT) and (2) judge thereafter whether (Q1) SI had been long enough to allow synchronization, (Q2) their motor response had been "reactive" (i.e., close to their RT) or delayed, or (Q3) whether SI was short or long. SI was denoted by the filling-up time of an annular "gauge." In principle, the "synchronization" key-press should be reactive for SI ≤ RT and delayed in proportion with SI for SI > RT. Instead, response time distributions were bimodal for the shortest (0 ms) and longest (500 ms) SIs and widely spread for intermediate SIs. To all three questions asked, subjects' responses strongly correlated with SI itself (r = 0.62-0.76) and barely with their actual response times (r = 0.03-0.42). Hence subjects' introspective judgments on their trial-by-trial potential capability to synchronize their motor response (Q1) and on their reactive vs. delayed response mode reflected the objective cause of their action rather than being "corrupted" by its outcome (namely their actual response time). That subjects could not reliably decide whether their motor response was reactive or delayed implies that they did not have retrospective access to (or did not remember) their motor decisions which amounts to say that they could not decide on the intentionality of their actions.

No MeSH data available.


Synchronization response times (RsT) as a function of SI in Experiments 1 (A) and 2 (B) of all five participants (different symbols) together with representative bimodal RsT distributions of participant SL for SI = 0 (a1) and SI = 500 ms (a2) as well as a representative cumulative Gaussian fitted to this subject's “Yes” responses to Q1 as a function of SI (a3). The dashed main diagonals in (A) and (B) show perfectly synchronized RsTs. The double arrowed right-angle lines in a3 point to this subject's RsT at 50% “Yes” responses (i.e., the mean of the fitted Gaussian), i.e., his point of subjective synchronization referred to SI (PSSSI).
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Figure 2: Synchronization response times (RsT) as a function of SI in Experiments 1 (A) and 2 (B) of all five participants (different symbols) together with representative bimodal RsT distributions of participant SL for SI = 0 (a1) and SI = 500 ms (a2) as well as a representative cumulative Gaussian fitted to this subject's “Yes” responses to Q1 as a function of SI (a3). The dashed main diagonals in (A) and (B) show perfectly synchronized RsTs. The double arrowed right-angle lines in a3 point to this subject's RsT at 50% “Yes” responses (i.e., the mean of the fitted Gaussian), i.e., his point of subjective synchronization referred to SI (PSSSI).

Mentions: Figure 2A presents mean RsTs for each participant (different symbols; keep in mind that RT and RsT refer to response time measured in speeded and in a synchronization response mode, respectively) as a function of SI in Experiment 1. This representation is not quite legitimate as at least three of the seven RsT means per subject were derived from bimodal RsT distributions (as assessed by Akaike Information Criterion, AIC; Akaike, 1974), with all subjects showing bimodal RsT distributions for SI = 0 and for SI = 500 ms. These bimodal RsT distributions for the two extreme SIs are exemplified in Figures 2a1,a2 for a typical subject, SL). The average difference between the means of the two distributions is 129 ms for SI = 0 and of 109 ms for SI = 500 ms. Averaging RsTs over such bimodal distributions accounts for subjects’ too early synchronization responses (i.e., RsTs below the main dashed diagonal) for the longest two SIs (400 and 500 ms; for such SIs, subjects show perfect synchronization under blocked SI conditions; Gorea et al., 2010). While the source of this bimodality is of critical interest in understanding the synchronization process (an issue addressed in an ongoing study), it is of little relevance for the present topical issue. It is worth noting, however, that the means of the fastest RsT distributions averaged over the five subjects for SI = 0 (249 ± 29.8 ms) are close to and not significantly different from their mean RTs assessed in the two preliminary (RT) experiments (230.6 ± 13 and 242.6 ± 12.1 ms). This suggests that in mixed SI blocks including SIs too short to synchronize with, subjects’ behavior alternates in about equal proportions between reactive and delayed response modes.


Introspecting on the Timing of One's Actions in a Visuo-Motor Synchronization Task.

Gzorea A, Rider D - Front Psychol (2011)

Synchronization response times (RsT) as a function of SI in Experiments 1 (A) and 2 (B) of all five participants (different symbols) together with representative bimodal RsT distributions of participant SL for SI = 0 (a1) and SI = 500 ms (a2) as well as a representative cumulative Gaussian fitted to this subject's “Yes” responses to Q1 as a function of SI (a3). The dashed main diagonals in (A) and (B) show perfectly synchronized RsTs. The double arrowed right-angle lines in a3 point to this subject's RsT at 50% “Yes” responses (i.e., the mean of the fitted Gaussian), i.e., his point of subjective synchronization referred to SI (PSSSI).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108554&req=5

Figure 2: Synchronization response times (RsT) as a function of SI in Experiments 1 (A) and 2 (B) of all five participants (different symbols) together with representative bimodal RsT distributions of participant SL for SI = 0 (a1) and SI = 500 ms (a2) as well as a representative cumulative Gaussian fitted to this subject's “Yes” responses to Q1 as a function of SI (a3). The dashed main diagonals in (A) and (B) show perfectly synchronized RsTs. The double arrowed right-angle lines in a3 point to this subject's RsT at 50% “Yes” responses (i.e., the mean of the fitted Gaussian), i.e., his point of subjective synchronization referred to SI (PSSSI).
Mentions: Figure 2A presents mean RsTs for each participant (different symbols; keep in mind that RT and RsT refer to response time measured in speeded and in a synchronization response mode, respectively) as a function of SI in Experiment 1. This representation is not quite legitimate as at least three of the seven RsT means per subject were derived from bimodal RsT distributions (as assessed by Akaike Information Criterion, AIC; Akaike, 1974), with all subjects showing bimodal RsT distributions for SI = 0 and for SI = 500 ms. These bimodal RsT distributions for the two extreme SIs are exemplified in Figures 2a1,a2 for a typical subject, SL). The average difference between the means of the two distributions is 129 ms for SI = 0 and of 109 ms for SI = 500 ms. Averaging RsTs over such bimodal distributions accounts for subjects’ too early synchronization responses (i.e., RsTs below the main dashed diagonal) for the longest two SIs (400 and 500 ms; for such SIs, subjects show perfect synchronization under blocked SI conditions; Gorea et al., 2010). While the source of this bimodality is of critical interest in understanding the synchronization process (an issue addressed in an ongoing study), it is of little relevance for the present topical issue. It is worth noting, however, that the means of the fastest RsT distributions averaged over the five subjects for SI = 0 (249 ± 29.8 ms) are close to and not significantly different from their mean RTs assessed in the two preliminary (RT) experiments (230.6 ± 13 and 242.6 ± 12.1 ms). This suggests that in mixed SI blocks including SIs too short to synchronize with, subjects’ behavior alternates in about equal proportions between reactive and delayed response modes.

Bottom Line: By means of a new visuo-motor synchronization paradigm we test the frequently made proposition that one's feeling of having voluntarily made a decision to act is in fact postdictively established contingent on the outcome of his action rather than on its aim.Instead, response time distributions were bimodal for the shortest (0 ms) and longest (500 ms) SIs and widely spread for intermediate SIs.To all three questions asked, subjects' responses strongly correlated with SI itself (r = 0.62-0.76) and barely with their actual response times (r = 0.03-0.42).

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes and CNRS Paris, France.

ABSTRACT
By means of a new visuo-motor synchronization paradigm we test the frequently made proposition that one's feeling of having voluntarily made a decision to act is in fact postdictively established contingent on the outcome of his action rather than on its aim. Subjects had to (1) synchronize a key-press with the end of a random synchronization interval (SI) shorter or longer than their reaction time (RT) and (2) judge thereafter whether (Q1) SI had been long enough to allow synchronization, (Q2) their motor response had been "reactive" (i.e., close to their RT) or delayed, or (Q3) whether SI was short or long. SI was denoted by the filling-up time of an annular "gauge." In principle, the "synchronization" key-press should be reactive for SI ≤ RT and delayed in proportion with SI for SI > RT. Instead, response time distributions were bimodal for the shortest (0 ms) and longest (500 ms) SIs and widely spread for intermediate SIs. To all three questions asked, subjects' responses strongly correlated with SI itself (r = 0.62-0.76) and barely with their actual response times (r = 0.03-0.42). Hence subjects' introspective judgments on their trial-by-trial potential capability to synchronize their motor response (Q1) and on their reactive vs. delayed response mode reflected the objective cause of their action rather than being "corrupted" by its outcome (namely their actual response time). That subjects could not reliably decide whether their motor response was reactive or delayed implies that they did not have retrospective access to (or did not remember) their motor decisions which amounts to say that they could not decide on the intentionality of their actions.

No MeSH data available.