Activation of action rules in action observation.

Visually perceiving an action may activate corresponding motor programs. This automatic motor activation can occur both for higher level (i.e., the goal of an action) and for lower level (i.e., the specific effector with which it is executed) aspects of an action. The authors used a tool-use action paradigm to experimentally dissociate priming effects for observing the target, the movement, or the target-to-movement mapping of a tool-use action. In 3 experiments, participants took turns in acting, observing the tool-use action of another person in trial n-1, and executing an action in trial n. Trial transitions from n-1 to n were manipulated in 4 conditions with (a) mapping repeated and movement and target changed, (b) target repeated and movement and mapping changed, (c) movement repeated and target and mapping changed, or (d) all components repeated. Results indicate priming effects for repeating the target-to-movement mapping (i.e., the action rule) of a tool-use action and suggest that a rather abstract action schema is activated during action observation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Compatibility of motion facilitates visuomotor synchronization.

Prior research indicates that synchronized tapping performance is very poor with flashing visual stimuli compared with auditory stimuli. Three finger-tapping experiments compared flashing visual metronomes with visual metronomes containing a spatial component, either compatible, incompatible, or orthogonal to the tapping action. In Experiment 1, synchronization success rates increased dramatically for spatiotemporal sequences of both geometric and biological forms over flashing sequences. In Experiment 2, synchronization performance was best when target sequences and movements were directionally compatible (i.e., simultaneously down), followed by orthogonal stimuli, and was poorest for incompatible moving stimuli and flashing stimuli. In Experiment 3, synchronization performance was best with auditory sequences, followed by compatible moving stimuli, and was worst for flashing and fading stimuli. Results indicate that visuomotor synchronization improves dramatically with compatible spatial information. However, an auditory advantage in sensorimotor synchronization persists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Negligible effect of spatial precuing on identification of single digits.

Examined the effects of spatial precuing on identification of a single object appearing in an otherwise empty visual field. A digit target was preceded by a valid, neutral, or invalid location cue, presented either peripherally or centrally. The target was followed by either a single mask or multiple masks covering the target and nontarget (empty) locations. Precuing significantly affected identification accuracy when multiple masks were used but had little effect when the target was followed by a single mask. The results strongly favor a model in which spatial precuing allows the contents of noncued locations to be excluded from decision (and possibly perception). Exclusion may or may not facilitate performance, depending on what is there to be excluded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experience matters: The impact of doing versus watching on infants' subsequent perception of tool-use events.

Prior work suggests that active experience affects infants' understanding of simple actions. The present studies compared the impact of active and observational experience on infants' ability to identify the goal of a novel tool-use event. Infants either received active training and practice in using a cane to retrieve an out-of-reach toy or had matched observational experience before taking part in a habituation paradigm that we used to assess infants' ability to identify the goal of another person's tool-use acts. Active training alone facilitated 10-month-old infants' ability to identify the goal of the tool-use event. Active experience using tools may enable infants to build motor representations of tool-use events that subsequently guide action perception and support action understanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Embodied rules in tool use: A tool-switching study.

In tool use, a transformation rule defines the relation between an operating movement and its distal effect. This rule is determined by the tool structure and requires no explicit definition. The present study investigates how humans represent and apply compatible and incompatible transformation rules in tool use. In Experiment 1, participants had to switch between tools for which the respective transformation rules were either the same or different. This way, rule repetitions could be dissociated from tool repetitions. In Experiment 2, the application of transformation rules in tool use was compared with the application of explicitly defined rules. In Experiment 3, actions of tool use were cued either by tool pictures or by written tool names. The results suggest that a transformation rule in tool use has a cognitive representation that is independent of the concrete tool incorporating it. Furthermore, its application differs from the application of an explicitly defined rule in terms of reduced top-down processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imitative response tendencies following observation of intransitive actions.

Clear and unequivocal evidence shows that observation of object affordances or transitive actions facilitates the activation of a compatible response. By contrast, the evidence showing response facilitation following observation of intransitive actions is less conclusive because automatic imitation and spatial compatibility have been confounded. Three experiments tested whether observation of a finger movement (i.e., an intransitive action) in a choice reaction-time task facilitates the corresponding finger movement response because of imitation, a common spatial code, or some combination of both factors. The priming effects of a spatial and an imitative stimulus were tested in combination (Experiment 1), in opposition (Experiment 2), and independently (Experiment 3). Contrary to previous findings, the evidence revealed significant contributions from both automatic imitation and spatial compatibility, but the priming effects from an automatic tendency to imitate declined significantly across a block of trials whereas the effects of spatial compatibility remained constant or increased slightly. These differential effects suggest that priming associated with automatic imitation is mediated by a different regime than priming associated with spatial compatibility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context effects on the processing of action-relevant object features.

In 4 experiments, we investigated the effects of object affordance in reach-to-grasp actions. Participants indicated whether a depicted small or large object was natural or manmade by means of different object-grasping responses (i.e., with a power or a precision grip). We observed that the size of the depicted object affected the grasping kinematics (grip aperture) and the reach-onset times of compatible and incompatible actions. Additional experiments showed that the effect of perceived object size on motor response was modulated by contextual action information and the observation of others’ actions with the object. Thus, beyond the observation of object affordance effects in natural grasping actions, this study suggests that the coupling between object perception and action is not static and obligatory. Behavioral effects of action-relevant object features seem rather to depend on contextual action information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lengthing the duration of response execution does not modulate blindness to action-compatible stimuli.

Action-compatible blindness refers to the finding that target stimuli are perceived less frequently if they are presented during the planning or execution of a compatible action (e.g., a left arrow presented during a left manual key press) than during an incompatible action (J. Müsseler and B. Hommel, 1997 a, b). We investigated the effect of lengthening the response execution phase in the action-compatible blindness paradigm by requiring subjects to tap a response key once or three times on the assumption that tapping three times would increase the duration of the execution phase of the response. Prior research (e.g., B. Stevanovski et al (2002); P. Wühr and J. Müsseler, [2001]) has shown that larger blindness effects are observed for targets presented during the execution phase of a response than after the response has been made. We investigated whether a larger blindness effect would be observed in the three-tap condition than in the one-tap condition, or whether lengthening the duration of the response would extend the time course of the blindness effect. Neither of these possibilities was supported by the data irrespective of whether the number of taps to be made was blocked or mixed within a block of trials. The results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The norm of self-interest and its effects on social action.

Four studies investigated whether people feel inhibited from engaging in social action incongruent with their apparent self-interest. Participants in Study 1 predicted that they would be evaluated negatively were they to take action on behalf of a cause in which they had no stake or in which they had a stake but held stake-incongruent attitudes. Participants in Study 2 reported both surprise and anger when a target person took action on behalf of a cause in which he or she had no stake or in which he or she held stake-incongruent attitudes. In Study 3, individuals felt more comfortable engaging in social action and expected others to respond more favorably toward their actions if the issue was described as more relevant to their own sex than to the opposite sex. In Study 4, the authors found that providing nonvested individuals with psychological standing rendered them as likely as vested individuals to undertake social action. The authors discuss the implications of these results for the relationship between vested interest, social action, and attitude–behavior consistency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hand to mouth: Automatic imitation across effector systems.

The effector dependence of automatic imitation was investigated using a stimulus–response compatibility (SRC) procedure during which participants were required to make an open or closed response with their hand or their mouth. The correct response for each trial was indicated by a pair of letters in Experiments 1 and 2 and by a colored square in Experiment 3. Each of these imperative stimuli was accompanied by task-irrelevant action images depicting a hand or mouth opening or closing. In relation to the response, the irrelevant stimulus was movement compatible or movement incompatible, and effector compatible or effector incompatible. A movement compatibility effect was observed for both hand and mouth responses. These movement compatibility effects were present when the irrelevant stimulus was effector compatible and when it was effector incompatible, but were smaller when the irrelevant stimulus and response effectors were incompatible. Consistent with the associative sequence learning (ASL) model of imitation, these findings indicate that automatic imitation is partially effector dependent and therefore that the effector dependence of intentional imitation reflects, at least in part, the nature of the mechanisms that mediate visuomotor translation for imitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional capture by irrelevant color singletons.

Four experiments investigated attentional capture by a color singleton in visual search for a nonsingleton target. B. S. Gibson and E. M. Kelsey (1998) found that a color singleton in a precuing array facilitated target discrimination at that location if the same color also signaled the target array onset. The authors found similar cuing effects regardless of whether the singleton color matched the target array and regardless of whether subjects could anticipate the singleton or target-array color. In Experiment 4, a color singleton captured attention when it appeared in the precuing array but not when it appeared in the target array. The results indicate that attentional control settings for displaywide attributes are imprecise: Although subjects may anticipate a specific color, they cannot avoid attentional capture by other irrelevant colors. In addition, the effect of irrelevant singletons depends on whether a target is simultaneously present in the array. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deciding how to act is not achieved by watching mental movies.

In the early days of research on visual imagery, it was believed that visual images are like pictures in one’s head. Only as the field matured did it come to be appreciated that visual images do not bear a first-order isomorphic relation to visual percepts. Now that the early days of research on motor imagery are coming to an end, it is important to ask whether motor images bear a first-order isomorphic relation to movements. We asked whether they do by focusing on internal simulations for motor planning. Our participants indicated which of two possible actions they preferred either by performing the preferred action or by indicating which action they would prefer to perform. We reasoned that if internal simulations of physical actions bear a first-order isomorphic relation to actual physical actions, the choices would be the same in the two conditions. They were not. We discuss the reasons for this outcome, including the adaptive advantage of a representational system for action which, like the representational system for vision, does not bear a first-order isomorphic relation to its external analog. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Programming saccadic eye movements.

This article addresses questions about the preparatory processes that immediately precede saccadic eye movements. Saccade latencies were measured in a task in which subjects were provided partial advance information about the spatial location of a target fixation. In one experiment, subjects were faster in initiating saccades when they knew either the direction or amplitude of the required movement in advance compared to a condition with equal uncertainty about the number of potential saccade targets but without knowledge of the parameters required to execute the movement. These results suggest that the direction and amplitude for an upcoming saccade were calculated separately, and not in a fixed serial order. In another experiment, subjects appear to have programmed the saccades more holistically—with computations of direction and amplitude parameters occurring simultaneously. The implications of these results for models of eye movement preparation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for motor simulation in imagined locomotion.

A series of experiments examined the role of the motor system in imagined movement, finding a strong relationship between imagined walking performance and the biomechanical information available during actual walking. Experiments 1 through 4 established the finding that real and imagined locomotion differ in absolute walking time. We then tested whether executed actions could provide a basis for imagined walking rate using 2 approaches. Experiments 5 and 6 used a perceptual-motor recalibration paradigm, finding that after physically walking in a treadmill virtual reality environment, actors recalibrated the time to imagine walking to a previously viewed target. This finding mirrors previous perceptual-motor recalibration work measuring actual walking to previously viewed targets. Experiments 7 and 8 used a dual-task paradigm in which actions performed concurrently with imagined walking increased the similarity between real and imagined walking time, but only when they were biomechanically consistent with the act of walking. The striking influence of biomechanical information on imagined locomotion provides evidence for shared motor systems in imagined and executed movements and is also directly relevant to the mechanisms involved in egocentric spatial updating of environmental layout. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of advance information about target location and visual feedback on movement planning and execution.

This study was designed to determine if movement planning strategies incorporating the use of visual feedback during manual aiming are specific to individual movements. Advance information about target location and visual context was manipulated using precues. Participants exhibited a shorter reaction time and a longer movement time when they were certain of the target location and that vision would be available. The longer movement time was associated with greater time after peak velocity. Under conditions of uncertainty, participants prepared for the worst-case scenario. That is, they spent more time organizing their movements and produced trajectories that would be expected from greater open-loop control. Our results are consistent with hierarchical movement planning in which knowledge of the movement goal is an essential ingredient of visual feedback utilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional control during visual search: the effect of irrelevant singletons

Four experiments investigated whether a highly salient color singleton can be ignored during serial search. Observers searched for a target letter among nontarget letters and were instructed to ignore an irrelevant, highly salient color singleton that was either compatible or incompatible with the response to the target letter. The results indicate that it was possible to prevent attentional capture by the irrelevant singleton only when both the target and the distractor color were known. When either the color of the target or the color of the to-be-ignored singleton were varied over trials, the irrelevant singleton captured attention. The ability to selectively filter singleton distractors during serial search depends on the presence of an attentional set for a specific feature value of both target and distractor. In the absence of a consistently predictable feature value of both target and distractor, top-down control is not possible.     

On the inclusion of externally controlled actions in action planning.

According to ideomotor theories, perceiving action effects produced by others triggers corresponding action representations in the observer. We tested whether this principle extends to actions performed by externally controlled limbs and tools. Participants performed a go–no-go version of a spatial compatibility task in which their own actions resulted in the movement of a limb or tool, whereas a second, externally controlled limb or tool was seen performing a complementary go–no-go task. Spatial compatibility effects, indicating inclusion of the externally controlled effector in action planning, were observed when the externally controlled limb was identical to the controlled limb (Experiment 1) and when actions of limbs and tools (Experiment 2) or pairs of tools (Experiment 3 and 4) were combined according to participants' motor experience. When participants acted together, controlling a tool each, spatial compatibility effects occurred regardless of motor experience (Experiment 5). These findings demonstrate that (a) externally controlled tool actions are included in action planning and (b) social context modulates how externally controlled actions are mapped onto action representations. Implications of these findings for theories of perception–action links and object processing are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

An analysis of ideomotor action.

This article presents a framework based on the work of R. H. Lotze (1852), W. James (1890), and A. G. Greenwald (1970) for understanding ideomotor actions that tend to arise when individuals watch others perform certain actions. Two principles of ideomotor action induction are distinguished: perceptual induction, in which people tend to perform the movements they see, and intentional induction, in which people tend to perform movements suited to achieve what they would like to see. In 3 experiments, ideomotor hand, head, and foot movements were studied while participants watched a ball traveling toward a target. Results showed strong support for intentional induction, weaker support for perceptual induction, and a strong impact of the effector studied. The representational basis of action induction (stimulus vs. goal representations) and the automaticity of the underlying processing (task-dependent vs. task-independent induction) were considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emergence of action categories in the child: Evidence from verb meanings.

In adults, action categories encompass 2 kinds of instances: self-action and observed action. This article proposes a model of how adult action categories emerge in children whose early categories are specific to self- or observed action. The model posits that these categories are extended to encompass both kinds of instances as children develop the ability to note parallels between themselves and others as initiators of action. For adults, these parallels involve goals, causal efficacy, and movement. It is argued that parallels involving movement, which are directly observable, would be noted first and that parallels involving causes and goals, which are not directly observable and require inferences about internal states of other people, would be noted only later. Three studies of children's verb meanings were carried out to examine the development of action categories and to evaluate the proposed model. 103 preschoolers served as Ss. Findings show that verbs first encode children's own actions and only later encode the observed actions of other people. Further, verbs that encode characteristic movements (e.g., "walk") are extended to encompass observed action earlier than verbs that encode change (e.g., "open"), supporting the proposed model. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Walking Perception by Walking Observers.

People frequently analyze the actions of other people for the purpose of action coordination. To understand whether such self-relative action perception differs from other-relative action perception, the authors had observers either compare their own walking speed with that of a point-light walker or compare the walking speeds of 2 point-light walkers. In Experiment 1, observers walked, bicycled, or stood while performing a gait-speed discrimination task. Walking observers demonstrated the poorest sensitivity to walking speed, suggesting that perception and performance of the same action alters visual-motion processes. Experiments 2-6 demonstrated that the processes used during self-relative and other-relative action perception differ significantly in their dependence on observers' previous motor experience, current motor effort, and potential for action coordination. These results suggest that the visual analysis of human motion during traditional laboratory studies can differ substantially from the visual analysis of human movement under more realistic conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)