Predicting the actions of others is critical to smooth social interactions. Prior work suggests that both understanding and anticipation of goal‐directed actions appears early in development. In this ...study, on‐line goal prediction was tested explicitly using an adaptation of Woodward’s (1998) paradigm for an eye‐tracking task. Twenty 11‐month‐olds were familiarized to movie clips of a hand reaching to grasp one of two objects. Then object locations were swapped, and the hand made an incomplete reach between the objects. Here, infants reliably made their first look from the hand to the familiarized goal object, now in a new location. A separate control condition of 20 infants familiarized to the same movements of an unfamiliar claw revealed the opposite pattern: reliable prediction to the familiarized location, rather than the familiarized object. This study suggests that by 11 months infants actively use goal analysis to generate on‐line predictions of an agent’s next action.
Since the discovery of mirror neurons in premotor and parietal areas of the macaque monkey, the idea that action and perception may share the same neural code has been of central interest in social, ...developmental, and cognitive neurosciences. A fundamental question concerns how a putative human mirror neuron system may be tuned to the motor experiences of the individual. The current study tested the hypothesis that prior motor experience modulated the sensorimotor mu and beta rhythms. Specifically, we hypothesized that these sensorimotor rhythms would be more desynchronized after active motor experience compared to passive observation experience. To test our hypothesis, we collected EEG from adult participants during the observation of a relatively novel action: an experimenter used a claw-like tool to pick up a toy. Prior to EEG collection, we trained one group of adults to perform this action with the tool (performers). A second group comprised trained video coders, who only had experience observing the action (observers). Both the performers and the observers had no prior motor and visual experience with the action. A third group of novices was also tested. Performers exhibited the greatest mu rhythm desynchronization in the 8-13 Hz band, particularly in the right hemisphere compared to observers and novices. This study is the first to contrast active tool-use experience and observation experience in the mu rhythm and to show modulation with relatively shorter amounts of experience than prior mirror neuron expertise studies. These findings are discussed with respect to its broader implication as a neural signature for a mechanism of early social learning.
A fundamental issue in cognitive neuroscience is how the brain encodes others' actions and intentions. In recent years, a potential advance in our knowledge on this issue is the discovery of mirror ...neurons in the motor cortex of the nonhuman primate. These neurons fire to both execution and observation of specific types of actions. Researchers use this evidence to fuel investigations of a human mirror system, suggesting a common neural code for perceptual and motor processes. Among the methods used for inferring mirror system activity in humans are changes in a particular frequency band in the electroencephalogram (EEG) called the mu rhythm. Mu frequency appears to decrease in amplitude (reflecting cortical activity) during both action execution and action observation. The current meta-analysis reviewed 85 studies (1,707 participants) of mu that infer human mirror system activity. Results demonstrated significant effect sizes for mu during execution (Cohen's d = 0.46, N = 701) as well as observation of action (Cohen's d = 0.31, N = 1,508), confirming a mirroring property in the EEG. A number of moderators were examined to determine the specificity of these effects. We frame these meta-analytic findings within the current discussion about the development and functions of a human mirror system, and conclude that changes in EEG mu activity provide a valid means for the study of human neural mirroring. Suggestions for improving the experimental and methodological approaches in using mu to study the human mirror system are offered.
Highlights • We compare spectral, topographic, and cortical source structural properties of mu desynchronization and spontaneous alpha band EEG across 12-month, 4 year, and adult subject groups. • ...Spontaneous upper and lower alpha band peaks increase with age, and central channels contribute more to spontaneous peaks in the upper alpha band in all age groups. • Mu desynchronization peaks in the upper alpha band for all groups, and has distributed fronto-parietal cortical representation.
•The EEG mu rhythm is reactive when performing and observing a specific action.•Currently, methodological issues impede integrating infant mu rhythm findings.•We outline methodological considerations ...for infant mu rhythm research.•We propose guidelines to promote cross laboratory infant mu rhythm comparisons.•Methodological topics include baseline, frequency bands, and experimental design.
The EEG mu rhythm, recorded from scalp regions overlying the sensorimotor cortex, appears to exhibit mirroring properties: It is reactive when performing an action and when observing another perform the same action. Recently, there has been an exponential increase in developmental mu rhythm research, partially due to the mu rhythm’s potential role in our understanding of others’ actions as well as a variety of other social and cognitive processes (e.g., imitation, theory of mind, language). Unfortunately, various methodological issues impede integrating these findings into a comprehensive theory of mu rhythm development. The present manuscript provides a review of the infant mu rhythm literature while focusing on current methodological problems that impede between study comparisons. By highlighting these issues and providing an in depth description and analysis we aim to heighten awareness and propose guidelines (when possible) that will promote rigorous infant mu rhythm research and facilitate between study comparisons. This paper is intended as a resource for developmental scientists, regardless of EEG expertise.
Recent work implicates a link between action control systems and action understanding. In this study, we investigated the role of the motor system in the development of visual anticipation of others’ ...actions. Twelve‐month‐olds engaged in behavioral and observation tasks. Containment activity, infants’ spontaneous engagement in producing containment actions; and gaze latency, how quickly they shifted gaze to the goal object of another’s containment actions, were measured. Findings revealed a positive relationship: infants who received the behavior task first evidenced a strong correlation between their own actions and their subsequent gaze latency of another’s actions. Learning over the course of trials was not evident. These findings demonstrate a direct influence of the motor system on online visual attention to others’ actions early in development.
The current study harnessed the variability in infants' neural and behavioral responses as a novel method for evaluating the potential relations between motor system activation and social behavior. ...We used electroencephalography (EEG) to record neural activity as 7-month-old infants observed and responded to the actions of an experimenter. To determine whether motor system activation predicted subsequent imitation behavior, we assessed event-related desynchronization (ERD) at central sites during action observation as a function of subsequent behavior. Greater mu desynchronization over central sites was observed when infants subsequently reproduced the experimenter's goal than when they did not reproduce the goal and instead selected the nongoal object. We also found that mu desynchronization during action execution predicted the infants' later propensity to reproduce the experimenter's goal-directed behavior. These results provide the first evidence that motor system activation predicts the imitation of other individuals' goals during infancy.
Recent reports of similar patterns of brain electrical activity (electroencephalogram: EEG) during action execution and observation, recorded from scalp locations over motor‐related regions in ...infants and adults, have raised the possibility that two foundational abilities – controlling one's own intentional actions and perceiving others’ actions – may be integrally related during ontogeny. However, to our knowledge, there are no published reports of the relations between developments in motor skill (i.e. recording actual motor skill performance) and EEG during both action execution and action observation. In the present study we collected EEG from 21 9‐month‐olds who were given opportunities to reach for toys and who also observed an experimenter reach for toys. Event‐related desynchronization (ERD) was computed from the EEG during the reaching events. We assessed infants’ reaching‐grasping competence, including reach latency, errors, preshaping of the hand, and bimanual reaches, and found that desynchronization recorded in scalp electrodes over motor‐related regions during action observation was associated with action competence during execution. Infants who were more competent reachers, compared to less competent reachers, exhibited greater ERD while observing reaching‐grasping. These results provide initial evidence for an early emerging neural system integrating one's own actions with the perception of others’ actions.
A neural mirror system predicts that developments in infants' motor experience should be associated with the strength of EEG mu desynchronization during action observation.To explore this, 9‐month‐old infants reached for toys and observed an experimenter reaching for toys while EEG activity was recorded in the mu frequency band. We found greater mu desynchronization in scalp electrodes located over motor‐related regions during action observation was associated with greater reach‐grasp competence, suggesting an early emerging neural system integrating one's own actions with the perception of others' actions.
Many psychological theories posit foundational links between two fundamental constructs: (1) our ability to produce, perceive, and represent action; and (2) our ability to understand the meaning and ...motivation behind the action (i.e. Theory of Mind; ToM). This position is contentious, however, and long‐standing competing theories of social‐cognitive development debate roles for basic action‐processing in ToM. Developmental research is key to investigating these hypotheses, but whether individual differences in neural and behavioral measures of motor action relate to social‐cognitive development is unknown. We examined 3‐ to 5‐year‐old children's (N = 26) EEG mu‐desynchronization during production of object‐directed action, and explored associations between mu‐desynchronization and children's behavioral motor skills, behavioral action‐representation abilities, and behavioral ToM. For children with high (but not low) mu‐desynchronization, motor skill related to action‐representation abilities, and action‐representation mediated relations between motor skill and ToM. Results demonstrate novel foundational links between action‐processing and ToM, suggesting that basic motor action may be a key mechanism for social‐cognitive development, thus shedding light on the origins and emergence of higher social cognition.
We investigated the behavioral and neural correlates of basic motor action to examine associations between these constructs and preschool children's developing theory of mind. Further we sought to clarify the functional correlates of the EEG mu rhythm—a rhythm in the brain that has been hypothesized to index action production as well as action representation, and that may constitute a neural mechanism facilitating links between developments in the motor and social cognitive domains. Results demonstrated that greater mu‐desynchronization moderated relations between action production and action representation skills (contrary to some simplified conceptualizations of mu‐rhythm), and critically also evinced clear links between action and theory of mind: For 3‐ to 5‐year‐old children with high mu‐desynchronization (indicating greater activation of underlying neural populations), action representation mediated the relation between action production and theory of mind, whereby better action production performance predicted better action representation performance which in turn predicted better theory‐of‐mind performance.
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