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The quick and the dead: when reaction beats intention.

Welchman AE, Stanley J, Schomers MR, Miall RC, Bülthoff HH - Proc. Biol. Sci. (2010)

Bottom Line: Within-subject analysis of movement times revealed a 10 per cent benefit for reactive actions.This was maintained when opponents performed dissimilar actions, and when participants competed against a computer, suggesting that the effect is not related to facilitation produced by action observation.Rather, faster ballistic movements may be a general property of reactive motor control, potentially providing a useful means of promoting survival.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Birmingham, Birmingham B15 2TT, UK. a.e.welchman@bham.ac.uk

ABSTRACT
Everyday behaviour involves a trade-off between planned actions and reaction to environmental events. Evidence from neurophysiology, neurology and functional brain imaging suggests different neural bases for the control of different movement types. Here we develop a behavioural paradigm to test movement dynamics for intentional versus reaction movements and provide evidence for a 'reactive advantage' in movement execution, whereby the same action is executed faster in reaction to an opponent. We placed pairs of participants in competition with each other to make a series of button presses. Within-subject analysis of movement times revealed a 10 per cent benefit for reactive actions. This was maintained when opponents performed dissimilar actions, and when participants competed against a computer, suggesting that the effect is not related to facilitation produced by action observation. Rather, faster ballistic movements may be a general property of reactive motor control, potentially providing a useful means of promoting survival.

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(a) Average movement execution times for each individual participant. Data show the harmonic mean execution time. Points connected by lines indicate the data from a single individual. Our data analysis considered the difference between these matched-pair responses. (b) The ‘reactive advantage’ (=initiated movement execution time−reactive movement execution time) for the three component phases of the movement sequence (1st: lift up from button 1, press down button 2; 2nd: lift up button 2, press down button 3; 3rd: lift up button 3, press down button 1), and for the total execution time (lifting up button 1 to pressing it down again having pressed button 2 and then 3). Data illustrate the between-subjects mean response. Error bars show s.e.m. (c) The reactive advantage expressed as a percentage change in the mean execution time. Data illustrate the between-subjects mean response with error bars showing s.e.m.
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RSPB20092123F2: (a) Average movement execution times for each individual participant. Data show the harmonic mean execution time. Points connected by lines indicate the data from a single individual. Our data analysis considered the difference between these matched-pair responses. (b) The ‘reactive advantage’ (=initiated movement execution time−reactive movement execution time) for the three component phases of the movement sequence (1st: lift up from button 1, press down button 2; 2nd: lift up button 2, press down button 3; 3rd: lift up button 3, press down button 1), and for the total execution time (lifting up button 1 to pressing it down again having pressed button 2 and then 3). Data illustrate the between-subjects mean response. Error bars show s.e.m. (c) The reactive advantage expressed as a percentage change in the mean execution time. Data illustrate the between-subjects mean response with error bars showing s.e.m.

Mentions: To investigate whether there was an advantage for reactive movements, we considered within-subject differences in movement execution times for trials on which participants initiated the movement sequence compared with trials on which they reacted following the movement of their opponent (figure 1c). We found that execution times were quicker by an average of 21 ms when participants reacted to their opponent's movement (figure 2a; t9 = 4.406, p = 0.002), an improvement of around 9 per cent. This ‘reactive advantage’ was most pronounced for the first movement of the three-button press sequence (figure 2b,c), quickening responses by around 14 per cent of the mean movement execution time. Moreover, the advantage was maximal when participants moved approximately 200 ms after the opponent (electronic supplementary material). However, as the reactive advantage in movement execution (mean = 21 ms) was less than the participant's reaction time to the movement of their opponent (mean = 207 ms), reactors rarely beat initiators (e.g. compare the difference between the red boxplots for a participant with the extent of their reaction time (blue boxplots) from figure 1c).


The quick and the dead: when reaction beats intention.

Welchman AE, Stanley J, Schomers MR, Miall RC, Bülthoff HH - Proc. Biol. Sci. (2010)

(a) Average movement execution times for each individual participant. Data show the harmonic mean execution time. Points connected by lines indicate the data from a single individual. Our data analysis considered the difference between these matched-pair responses. (b) The ‘reactive advantage’ (=initiated movement execution time−reactive movement execution time) for the three component phases of the movement sequence (1st: lift up from button 1, press down button 2; 2nd: lift up button 2, press down button 3; 3rd: lift up button 3, press down button 1), and for the total execution time (lifting up button 1 to pressing it down again having pressed button 2 and then 3). Data illustrate the between-subjects mean response. Error bars show s.e.m. (c) The reactive advantage expressed as a percentage change in the mean execution time. Data illustrate the between-subjects mean response with error bars showing s.e.m.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2871853&req=5

RSPB20092123F2: (a) Average movement execution times for each individual participant. Data show the harmonic mean execution time. Points connected by lines indicate the data from a single individual. Our data analysis considered the difference between these matched-pair responses. (b) The ‘reactive advantage’ (=initiated movement execution time−reactive movement execution time) for the three component phases of the movement sequence (1st: lift up from button 1, press down button 2; 2nd: lift up button 2, press down button 3; 3rd: lift up button 3, press down button 1), and for the total execution time (lifting up button 1 to pressing it down again having pressed button 2 and then 3). Data illustrate the between-subjects mean response. Error bars show s.e.m. (c) The reactive advantage expressed as a percentage change in the mean execution time. Data illustrate the between-subjects mean response with error bars showing s.e.m.
Mentions: To investigate whether there was an advantage for reactive movements, we considered within-subject differences in movement execution times for trials on which participants initiated the movement sequence compared with trials on which they reacted following the movement of their opponent (figure 1c). We found that execution times were quicker by an average of 21 ms when participants reacted to their opponent's movement (figure 2a; t9 = 4.406, p = 0.002), an improvement of around 9 per cent. This ‘reactive advantage’ was most pronounced for the first movement of the three-button press sequence (figure 2b,c), quickening responses by around 14 per cent of the mean movement execution time. Moreover, the advantage was maximal when participants moved approximately 200 ms after the opponent (electronic supplementary material). However, as the reactive advantage in movement execution (mean = 21 ms) was less than the participant's reaction time to the movement of their opponent (mean = 207 ms), reactors rarely beat initiators (e.g. compare the difference between the red boxplots for a participant with the extent of their reaction time (blue boxplots) from figure 1c).

Bottom Line: Within-subject analysis of movement times revealed a 10 per cent benefit for reactive actions.This was maintained when opponents performed dissimilar actions, and when participants competed against a computer, suggesting that the effect is not related to facilitation produced by action observation.Rather, faster ballistic movements may be a general property of reactive motor control, potentially providing a useful means of promoting survival.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Birmingham, Birmingham B15 2TT, UK. a.e.welchman@bham.ac.uk

ABSTRACT
Everyday behaviour involves a trade-off between planned actions and reaction to environmental events. Evidence from neurophysiology, neurology and functional brain imaging suggests different neural bases for the control of different movement types. Here we develop a behavioural paradigm to test movement dynamics for intentional versus reaction movements and provide evidence for a 'reactive advantage' in movement execution, whereby the same action is executed faster in reaction to an opponent. We placed pairs of participants in competition with each other to make a series of button presses. Within-subject analysis of movement times revealed a 10 per cent benefit for reactive actions. This was maintained when opponents performed dissimilar actions, and when participants competed against a computer, suggesting that the effect is not related to facilitation produced by action observation. Rather, faster ballistic movements may be a general property of reactive motor control, potentially providing a useful means of promoting survival.

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