Faculty Bibliography

Interpreting iconic gestures can be challenging for children. Here, we explore the features and functions of iconic gestures that make them more challenging for young children to interpret than instrumental actions. In Study 1, we show that 2.5-year-olds are able to glean size information from handshape in a simple gesture, although their performance is significantly worse than 4-year-olds'. Studies 2 to 4 explore the boundary conditions of 2.5-year-olds' gesture understanding. In Study 2, 2.5-year-old children have an easier time interpreting size information in hands that reach than in hands that gesture. In Study 3, we tease apart the perceptual features and functional objectives of reaches and gestures. We created a context in which an action has the perceptual features of a reach (extending the hand toward an object) but serves the function of a gesture (the object is behind a barrier and not obtainable; the hand thus functions to represent, rather than reach for, the object). In this context, children struggle to interpret size information in the hand, suggesting that gesture's representational function (rather than its perceptual features) is what makes it hard for young children to interpret. A distance control (Study 4) in which a person holds a box in gesture space (close to the body) demonstrates that children's difficulty interpreting static gesture cannot be attributed to the physical distance between a gesture and its referent. Together, these studies provide evidence that children's struggle to interpret iconic gesture may stem from its status as representational action. (PsycINFO Database Record

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.

The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-months-old infants. To measure online anticipation of actions infants watched videos where the actor's hand provided kinematic information (in its orientation) about the type of object that the actor was going to reach for. The actor's hand orientation either matched the orientation of a rod (congruent cue) or did not match the orientation of the rod (incongruent cue). To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first) × 2 (congruent kinematic cue vs. incongruent kinematic cue) between-subjects design. We show that 13-months-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues-suggesting that short-term experience changes attention to kinematics.

The target article argues that developmental processes are key to understanding the mirror neuron system, yet neglects several bodies of developmental research that are informative for doing so. Infants' actions and action understanding are structured by goals, and the former lends structure to the latter. Evaluating the origins and functions of mirror neurons depends on integrating investigations of neural, social-cognitive and motor development.