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Justin Fine

Arizona State University, Psychology, Graduate Student

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Supervisors: Eric Amazeen

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University of Cambridge

Abhijit Abhik Das

IUBAT-International University Of Business Agriculture and Technology.

Sorbonne University

Université de Montréal

University of California, San Diego

Emiliano Rustighi

Sorbonne University

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Papers by Justin Fine

Neural oscillations reflect latent learning states underlying dual-context sensorimotor adaptation

by Justin Fine and Marco Santello

A B S T R A C T Recent studies have suggested that individuals can form multiple motor memories w... more A B S T R A C T Recent studies have suggested that individuals can form multiple motor memories when simultaneously adapting to multiple, but oppositely-oriented perturbations. These findings predict that individuals detect the change in learning context, allowing the selective initialization and update of motor memories. However, previous elec-trophysiological studies of sensorimotor adaptation have not identified a neural mechanism supporting the detection of a context switch and adaptation to separate contexts. Here, we tested the hypothesis that such a mechanism is identifiable through neural oscillations measured through EEG. Human participants learned to manipulate an object in two opposite contexts (mass distribution). This task was designed based on previous work showing that people can adapt to both contexts. We found that sensorimotor α and β, and medial frontal θ frequency bands all exhibited different response patterns with respect to the error in each context. To determine whether any frequency's responses to error were distinctly related to a switch in context, we predicted single-trial EEG data from a computational learning model that can adapt to multiple contexts simultaneously based on a switching mechanism. This analysis revealed that only medial frontal θ was predicted by a component of the model state that adapts to errors based on a context switch. In contrast, α and β were predicted by a model state that was updated from performance errors independent of the context. These findings provide novel evidence showing that sensorimotor and medial frontal oscillations are predicted by different adaptation processes, and that changes in medial frontal activity may indicate the formation of motor memories by responding to changes in learning context.

Perceived Heaviness in the Context of Newton's Second Law: Combined Effects of Muscle Activity and Lifting Kinematics

Journal of experimental psychology. Human perception and performance, Jan 5, 2015

Researchers generally agree that perceived heaviness is based on the actions associated with unsu... more Researchers generally agree that perceived heaviness is based on the actions associated with unsupported holding. Psychophysical research has supported this idea, as has psychophysiological research connecting muscle activity to the perceptions of heaviness and effort. However, the role of muscle activity in the context of the resulting motions has not been investigated. In the present study, perceptions of heaviness were recorded along with the electromyogram (EMG) of the lifting muscle and peak acceleration of the lift. Consistent with predictions derived from Newton's Second Law of motion (Force = Mass×Acceleration), normal and illusory perceptions of heaviness were a function of the ratio of muscle activity to lifting acceleration. These results identify a psychophysiological mechanism for heaviness perception based on the forces and motions associated with unsupported holding. (PsycINFO Database Record

Perceived Heaviness in the Context of Newtonâs Second Law: Combined Effects of Muscle Activity and Lifting Kinematics

Journal of Experimental Psychology: Human Perception and Performance, 2015

Researchers generally agree that perceived heaviness is based on the actions associated with unsu... more Researchers generally agree that perceived heaviness is based on the actions associated with unsupported holding. Psychophysical research has supported this idea, as has psychophysiological research connecting muscle activity to the perceptions of heaviness and effort. However, the role of muscle activity in the context of the resulting motions has not been investigated. In the present study, perceptions of heaviness were recorded along with the electromyogram (EMG) of the lifting muscle and peak acceleration of the lift. Consistent with predictions derived from Newton&amp;amp;amp;amp;#39;s Second Law of motion (Force = Mass×Acceleration), normal and illusory perceptions of heaviness were a function of the ratio of muscle activity to lifting acceleration. These results identify a psychophysiological mechanism for heaviness perception based on the forces and motions associated with unsupported holding. (PsycINFO Database Record

$Research paper thumbnail of Experimental control of scaling behavior: what is not fractal?$

Experimental control of scaling behavior: what is not fractal?

Experimental Brain Research, 2015

A review of the literature suggests that most psychological behaviors exhibit fractal scaling in ... more A review of the literature suggests that most psychological behaviors exhibit fractal scaling in one form or another. Center of pressure measurements reveal fractal structure while people maintain upright posture (e.g., as do intertap intervals (ITIs) in continuation tapping paradigms (Torre and Abstract The list of psychological processes thought to exhibit fractal behavior is growing. Although some might argue that the seeming ubiquity of fractal patterns illustrates their significance, unchecked growth of that list jeopardizes their relevance. It is important to identify when a single behavior is and is not fractal in order to make meaningful conclusions about the processes underlying those patterns. The hypothesis tested in the present experiment is that fractal patterns reflect the enactment of control. Participants performed two steering tasks: steering on a straight track and steering on a circular track. Although each task could be accomplished by holding the steering wheel at a constant angle, steering around a curve may require more constant control, at least from a psychological standpoint. Results showed that evidence for fractal behavior was strongest for the circular track; straight tracks showed evidence of two scaling regions. We argue from those results that, going forward, the goal of the fractal literature should be to bring scaling behavior under experimental control.

$Results Table 1 shows the mean Hurst exponent as a function of speed, track, and compatibility. From that table, three fea- tures are apparent. The most notable trend is that Hurst exponents appear much smaller for the straight track than for circular tracks. Also, it appears that the wheel-compat- ible condition produced larger exponents when steering on the circular tracks but not on the straight track. More inter- esting, though, is the range of Hurst exponents present in Table 1. Hurst exponents on the straight track appear either very close to 0.50, the theoretical value for non-fractal (random) behavior, or much less than 0.50, the theoretical range of antipersistent behavior. Hurst exponents on circular tracks are much higher and suggestive of fractal behavior. tures are apparent. The most notable trend is that Hurst tracks are much higher and suggestive of fractal behavior.$

Hysteresis in Categorization: Fuzzy Logic Makes Fuzzy Boundaries

by Justin Fine and Thomas Crawford

PsycEXTRA Dataset, 2000

Emergent Complexity Matching in Interpersonal Coordination: Local Dynamics and Global Variability

by Justin Fine and Eric Amazeen

Rhythmic coordination with stimuli and other people’s movements containing variable or unpredicta... more Rhythmic coordination with stimuli and other people’s movements containing variable or unpredictable
fluctuations might involve distinct processes: detecting the fluctuation structure and tuning to or
matching the structure’s temporal complexity. This framework predicts that global tuning and local
parameter adjustments (e.g., position, velocity or phase) can operate independently during coordination
(Marmelat & Delignières, 2012). Alternatively, we propose that complexity matching is a result of local
phase adjustments during coordination (Delignières & Marmelat, 2014; Torre, Varlet, & Marmelat,
2013). The current study examined this relationship in a rhythmic interpersonal coordination task. Dyads
coordinated swinging pendulums that differed in their uncoupled frequencies (detuning). We predicted
that frequency detuning would require increased local corrections to maintain the intended phase pattern
(in phase). This was expected to yield a relative phase shift accompanied by a change in period
complexity and matching. Experimental data and numerical modeling of the pendulum dynamics
confirmed our predictions. Increased relative phase shifts occurred simultaneously with increased
dissociation between individuals’ movement period complexity. This provided evidence that global
complexity matching is intricately linked to local movement adjustments and is not a distinct coordination
mechanism. These findings are considered with respect to dynamical and computational approaches
to interpersonal coordination.

$Figure 3. Mean amplitude as a function of pendulum frequency (; \Q: 25 radians [rads]/s). Bars represent standard errors. An example of the full period series for two participants is shown in Figure 4. To determine whether specific values of pen-$

$Figure 6. Absolute difference in dyads’ movement period fractal expo- nents (Ac) as a function of frequency detuning (Aw; radians [rads]/s). All data points are displayed, with the significant quadratic regression line superimposed.$

$Note. Values of w represent radians per second. Cc; = linear stiffness; C39 = nonlinear stiffness; cy, = linear damping; co3 = Rayleigh damping; \Q: 28 Cy); = Van der Pol damping. Average Stiffness and Damping (Friction) Parameter Coefficients for the Five Levels of Pendulum Frequency (w$

Manual Coordination with Intermittent Targets: Velocity Information for Prospective Control

Acta Psychologica, 2014

Tracking a moving target requires that information concerning the current and future state of a t... more Tracking a moving target requires that information concerning the current and future state of a target is available, allowing prospective control of the tracking effector. Eye movement research has shown that prospective visual tracking is achievable during conditions of both visible and occluded targets. The ability to track visually occluded targets has been interpreted as individuals integrating target velocity into eye movement motor plans. It has not been fully established that velocity plays a similar role in other types of tracking behavior. To examine whether target velocity is also used in manual tracking, numerical predictions and a validation experiment were conducted. Predictions indicated that, if individuals utilize target velocity during coordination, increases in visual occlusion periods should yield increased phase lag between target and hand, proportional to the occlusion period. Predictions also suggest that increased occlusion yields increased coordination variability. An experiment having participants coordinate with the same stimuli and occlusion conditions was conducted to verify the predictions. Comparison of prediction and experimental results provides strong agreement that individuals use target velocity to prospectively control coordinated movements.

Stabilizing perceptual-motor asymmetries during social coordination

Human Movement Science

The current paper presents two studies that examine how we compensate for asymmetries during inte... more The current paper presents two studies that examine how we compensate for asymmetries during interpersonal coordination. It was predicted that destabilizing effects of asymmetries are offset through the recruitment and suppression of motor degrees-offreedom (df). In Experiment 1, this effect was examined by having participants coordinate line movements of different orientations. Greater asymmetries between participants yielded greater spatial deviation from the intended orientation, suggesting a recruitment of df. In Experiment 2, participants coordinated circle and line movements. Results showed that line became more circular and circles became more linear, specifically along the axis of the line movements. These results suggested that df were both systematically suppressed (in the case of circle movements) and recruited (in the case of line movements) to stabilize an asymmetric coordination task.

How high can you jump? Children’s Perception of Affordances for Self and Others with Different Abilities

by Justin Fine, Heidi Kloos, and Mona Jenkins

The current study investigated whether children and adults can distinguish between actions they a... more The current study investigated whether children and adults can distinguish between actions they are afforded and those afforded to an actor. Participants judged the maximum height they could reach while jumping and they judged the maximum height that the actor could reach while jumping. They did so with and without a weighted backpack, and they did so with and without walking several laps. Results show that before the addition of the weighted backpack, participants rated the actor's abilities as much closer to their own. While wearing the weighted backpack and then walking with it, participants' estimates decreased for themselves, but remained mostly unchanged for the adult.

Congruency Effects in Interpersonal Coordination

Journal of Experimental Psychology: Human Perception and Performance

Research on interpersonal coordination has demonstrated that incongruent tasks lead to unintended... more Research on interpersonal coordination has demonstrated that incongruent tasks lead to unintended movements in the orthogonal plane. These effects have been interpreted using both an embodied simulation and coordination dynamics approach. To distinguish between these two perspectives, two experiments examined whether this congruency effect is best defined spatially or anatomically. In the first experiment, participants coordinated congruent and incongruent rhythmic arm movements with an actor. To dissociate spatial and anatomical congruency, the actor was rotated 90°in the coronal plane for half of the trials. In the second experiment, participants coordinated movements of different limbs (leg and arm). Spatial and anatomical congruency was dissociated here by rotating the actor in the transverse plane. In both experiments, the unintended movements associated with the congruency effect emerged as a function of spatial congruency; there was no congruency effect associated with anatomical congruency. The data suggests that these unintended movements represent the recruitment of additional df necessary to stabilize an unstable form of coordination.

Cultural variations on the SIMS model

Behavioral and …, Jan 1, 2010

Paula M. Niedenthal Centre National de la Recherche Scientifique (CNRS) and Clermont Université, ... more

Interpersonal Fitts' law: when two perform as one

Experimental brain research, Jan 1, 2011

Intra-and interpersonal coordination was investigated using a bimanual Fitts' law task. Participa... more Intra-and interpersonal coordination was investigated using a bimanual Fitts' law task. Participants tapped rhythmically between pairs of targets. Tapping was performed with one hand (unimanual), two hands (intrapersonal coordination), and one hand together with another participant (interpersonal coordination). The sizes and distances of targets in a pair were manipulated independently for each hand. When target difficulty was unequal across hands, movement times were similar in the coordination conditions, in violation of Fitts' law. Processing speed (measured by index of performance) increased for more difficult tasks, suggesting increased attention, even for dyads. These findings suggest that similar processes, not captured by centralized control, guide coordination for both individuals and dyads. Measures of coordination, though, still showed stronger coordination tendencies for intrapersonal coordination, indicating a possible role for centralized mechanisms.

Neural oscillations reflect latent learning states underlying dual-context sensorimotor adaptation

by Justin Fine and Marco Santello

A B S T R A C T Recent studies have suggested that individuals can form multiple motor memories w... more A B S T R A C T Recent studies have suggested that individuals can form multiple motor memories when simultaneously adapting to multiple, but oppositely-oriented perturbations. These findings predict that individuals detect the change in learning context, allowing the selective initialization and update of motor memories. However, previous elec-trophysiological studies of sensorimotor adaptation have not identified a neural mechanism supporting the detection of a context switch and adaptation to separate contexts. Here, we tested the hypothesis that such a mechanism is identifiable through neural oscillations measured through EEG. Human participants learned to manipulate an object in two opposite contexts (mass distribution). This task was designed based on previous work showing that people can adapt to both contexts. We found that sensorimotor α and β, and medial frontal θ frequency bands all exhibited different response patterns with respect to the error in each context. To determine whether any frequency's responses to error were distinctly related to a switch in context, we predicted single-trial EEG data from a computational learning model that can adapt to multiple contexts simultaneously based on a switching mechanism. This analysis revealed that only medial frontal θ was predicted by a component of the model state that adapts to errors based on a context switch. In contrast, α and β were predicted by a model state that was updated from performance errors independent of the context. These findings provide novel evidence showing that sensorimotor and medial frontal oscillations are predicted by different adaptation processes, and that changes in medial frontal activity may indicate the formation of motor memories by responding to changes in learning context.

Perceived Heaviness in the Context of Newton's Second Law: Combined Effects of Muscle Activity and Lifting Kinematics

Journal of experimental psychology. Human perception and performance, Jan 5, 2015

Researchers generally agree that perceived heaviness is based on the actions associated with unsu... more Researchers generally agree that perceived heaviness is based on the actions associated with unsupported holding. Psychophysical research has supported this idea, as has psychophysiological research connecting muscle activity to the perceptions of heaviness and effort. However, the role of muscle activity in the context of the resulting motions has not been investigated. In the present study, perceptions of heaviness were recorded along with the electromyogram (EMG) of the lifting muscle and peak acceleration of the lift. Consistent with predictions derived from Newton's Second Law of motion (Force = Mass×Acceleration), normal and illusory perceptions of heaviness were a function of the ratio of muscle activity to lifting acceleration. These results identify a psychophysiological mechanism for heaviness perception based on the forces and motions associated with unsupported holding. (PsycINFO Database Record

Perceived Heaviness in the Context of Newtonâs Second Law: Combined Effects of Muscle Activity and Lifting Kinematics

Journal of Experimental Psychology: Human Perception and Performance, 2015

Researchers generally agree that perceived heaviness is based on the actions associated with unsu... more Researchers generally agree that perceived heaviness is based on the actions associated with unsupported holding. Psychophysical research has supported this idea, as has psychophysiological research connecting muscle activity to the perceptions of heaviness and effort. However, the role of muscle activity in the context of the resulting motions has not been investigated. In the present study, perceptions of heaviness were recorded along with the electromyogram (EMG) of the lifting muscle and peak acceleration of the lift. Consistent with predictions derived from Newton&amp;amp;amp;amp;#39;s Second Law of motion (Force = Mass×Acceleration), normal and illusory perceptions of heaviness were a function of the ratio of muscle activity to lifting acceleration. These results identify a psychophysiological mechanism for heaviness perception based on the forces and motions associated with unsupported holding. (PsycINFO Database Record

$Research paper thumbnail of Experimental control of scaling behavior: what is not fractal?$

Experimental control of scaling behavior: what is not fractal?

Experimental Brain Research, 2015

A review of the literature suggests that most psychological behaviors exhibit fractal scaling in ... more A review of the literature suggests that most psychological behaviors exhibit fractal scaling in one form or another. Center of pressure measurements reveal fractal structure while people maintain upright posture (e.g., as do intertap intervals (ITIs) in continuation tapping paradigms (Torre and Abstract The list of psychological processes thought to exhibit fractal behavior is growing. Although some might argue that the seeming ubiquity of fractal patterns illustrates their significance, unchecked growth of that list jeopardizes their relevance. It is important to identify when a single behavior is and is not fractal in order to make meaningful conclusions about the processes underlying those patterns. The hypothesis tested in the present experiment is that fractal patterns reflect the enactment of control. Participants performed two steering tasks: steering on a straight track and steering on a circular track. Although each task could be accomplished by holding the steering wheel at a constant angle, steering around a curve may require more constant control, at least from a psychological standpoint. Results showed that evidence for fractal behavior was strongest for the circular track; straight tracks showed evidence of two scaling regions. We argue from those results that, going forward, the goal of the fractal literature should be to bring scaling behavior under experimental control.

$Results Table 1 shows the mean Hurst exponent as a function of speed, track, and compatibility. From that table, three fea- tures are apparent. The most notable trend is that Hurst exponents appear much smaller for the straight track than for circular tracks. Also, it appears that the wheel-compat- ible condition produced larger exponents when steering on the circular tracks but not on the straight track. More inter- esting, though, is the range of Hurst exponents present in Table 1. Hurst exponents on the straight track appear either very close to 0.50, the theoretical value for non-fractal (random) behavior, or much less than 0.50, the theoretical range of antipersistent behavior. Hurst exponents on circular tracks are much higher and suggestive of fractal behavior. tures are apparent. The most notable trend is that Hurst tracks are much higher and suggestive of fractal behavior.$

Hysteresis in Categorization: Fuzzy Logic Makes Fuzzy Boundaries

by Justin Fine and Thomas Crawford

PsycEXTRA Dataset, 2000

Emergent Complexity Matching in Interpersonal Coordination: Local Dynamics and Global Variability

by Justin Fine and Eric Amazeen

Rhythmic coordination with stimuli and other people’s movements containing variable or unpredicta... more Rhythmic coordination with stimuli and other people’s movements containing variable or unpredictable
fluctuations might involve distinct processes: detecting the fluctuation structure and tuning to or
matching the structure’s temporal complexity. This framework predicts that global tuning and local
parameter adjustments (e.g., position, velocity or phase) can operate independently during coordination
(Marmelat & Delignières, 2012). Alternatively, we propose that complexity matching is a result of local
phase adjustments during coordination (Delignières & Marmelat, 2014; Torre, Varlet, & Marmelat,
2013). The current study examined this relationship in a rhythmic interpersonal coordination task. Dyads
coordinated swinging pendulums that differed in their uncoupled frequencies (detuning). We predicted
that frequency detuning would require increased local corrections to maintain the intended phase pattern
(in phase). This was expected to yield a relative phase shift accompanied by a change in period
complexity and matching. Experimental data and numerical modeling of the pendulum dynamics
confirmed our predictions. Increased relative phase shifts occurred simultaneously with increased
dissociation between individuals’ movement period complexity. This provided evidence that global
complexity matching is intricately linked to local movement adjustments and is not a distinct coordination
mechanism. These findings are considered with respect to dynamical and computational approaches
to interpersonal coordination.

$Figure 3. Mean amplitude as a function of pendulum frequency (; \Q: 25 radians [rads]/s). Bars represent standard errors. An example of the full period series for two participants is shown in Figure 4. To determine whether specific values of pen-$

$Figure 6. Absolute difference in dyads’ movement period fractal expo- nents (Ac) as a function of frequency detuning (Aw; radians [rads]/s). All data points are displayed, with the significant quadratic regression line superimposed.$

$Note. Values of w represent radians per second. Cc; = linear stiffness; C39 = nonlinear stiffness; cy, = linear damping; co3 = Rayleigh damping; \Q: 28 Cy); = Van der Pol damping. Average Stiffness and Damping (Friction) Parameter Coefficients for the Five Levels of Pendulum Frequency (w$

Manual Coordination with Intermittent Targets: Velocity Information for Prospective Control

Acta Psychologica, 2014

Tracking a moving target requires that information concerning the current and future state of a t... more Tracking a moving target requires that information concerning the current and future state of a target is available, allowing prospective control of the tracking effector. Eye movement research has shown that prospective visual tracking is achievable during conditions of both visible and occluded targets. The ability to track visually occluded targets has been interpreted as individuals integrating target velocity into eye movement motor plans. It has not been fully established that velocity plays a similar role in other types of tracking behavior. To examine whether target velocity is also used in manual tracking, numerical predictions and a validation experiment were conducted. Predictions indicated that, if individuals utilize target velocity during coordination, increases in visual occlusion periods should yield increased phase lag between target and hand, proportional to the occlusion period. Predictions also suggest that increased occlusion yields increased coordination variability. An experiment having participants coordinate with the same stimuli and occlusion conditions was conducted to verify the predictions. Comparison of prediction and experimental results provides strong agreement that individuals use target velocity to prospectively control coordinated movements.

Stabilizing perceptual-motor asymmetries during social coordination

Human Movement Science

The current paper presents two studies that examine how we compensate for asymmetries during inte... more The current paper presents two studies that examine how we compensate for asymmetries during interpersonal coordination. It was predicted that destabilizing effects of asymmetries are offset through the recruitment and suppression of motor degrees-offreedom (df). In Experiment 1, this effect was examined by having participants coordinate line movements of different orientations. Greater asymmetries between participants yielded greater spatial deviation from the intended orientation, suggesting a recruitment of df. In Experiment 2, participants coordinated circle and line movements. Results showed that line became more circular and circles became more linear, specifically along the axis of the line movements. These results suggested that df were both systematically suppressed (in the case of circle movements) and recruited (in the case of line movements) to stabilize an asymmetric coordination task.

How high can you jump? Children’s Perception of Affordances for Self and Others with Different Abilities

by Justin Fine, Heidi Kloos, and Mona Jenkins

The current study investigated whether children and adults can distinguish between actions they a... more The current study investigated whether children and adults can distinguish between actions they are afforded and those afforded to an actor. Participants judged the maximum height they could reach while jumping and they judged the maximum height that the actor could reach while jumping. They did so with and without a weighted backpack, and they did so with and without walking several laps. Results show that before the addition of the weighted backpack, participants rated the actor's abilities as much closer to their own. While wearing the weighted backpack and then walking with it, participants' estimates decreased for themselves, but remained mostly unchanged for the adult.

Congruency Effects in Interpersonal Coordination

Journal of Experimental Psychology: Human Perception and Performance

Research on interpersonal coordination has demonstrated that incongruent tasks lead to unintended... more Research on interpersonal coordination has demonstrated that incongruent tasks lead to unintended movements in the orthogonal plane. These effects have been interpreted using both an embodied simulation and coordination dynamics approach. To distinguish between these two perspectives, two experiments examined whether this congruency effect is best defined spatially or anatomically. In the first experiment, participants coordinated congruent and incongruent rhythmic arm movements with an actor. To dissociate spatial and anatomical congruency, the actor was rotated 90°in the coronal plane for half of the trials. In the second experiment, participants coordinated movements of different limbs (leg and arm). Spatial and anatomical congruency was dissociated here by rotating the actor in the transverse plane. In both experiments, the unintended movements associated with the congruency effect emerged as a function of spatial congruency; there was no congruency effect associated with anatomical congruency. The data suggests that these unintended movements represent the recruitment of additional df necessary to stabilize an unstable form of coordination.

Cultural variations on the SIMS model

Behavioral and …, Jan 1, 2010

Paula M. Niedenthal Centre National de la Recherche Scientifique (CNRS) and Clermont Université, ... more

Interpersonal Fitts' law: when two perform as one

Experimental brain research, Jan 1, 2011

Intra-and interpersonal coordination was investigated using a bimanual Fitts' law task. Participa... more Intra-and interpersonal coordination was investigated using a bimanual Fitts' law task. Participants tapped rhythmically between pairs of targets. Tapping was performed with one hand (unimanual), two hands (intrapersonal coordination), and one hand together with another participant (interpersonal coordination). The sizes and distances of targets in a pair were manipulated independently for each hand. When target difficulty was unequal across hands, movement times were similar in the coordination conditions, in violation of Fitts' law. Processing speed (measured by index of performance) increased for more difficult tasks, suggesting increased attention, even for dyads. These findings suggest that similar processes, not captured by centralized control, guide coordination for both individuals and dyads. Measures of coordination, though, still showed stronger coordination tendencies for intrapersonal coordination, indicating a possible role for centralized mechanisms.