Sandra C. Lozano

Communicative Gestures Facilitate Problem Solving for Both Communicators and Recipients

Gestures are a common, integral part of communication. Here, we investigate the roles of gesture and speech in explanations, both for communicators and recipients. Communicators explained how to assemble a simple object, using either speech with gestures or gestures alone. Gestures used for explaining included pointing and exhibiting to indicate parts, action models to demonstrate assembly, and gestures used to convey narrative structure. Communicators using gestures alone learned assembly better, making fewer assembly errors than those communicating via speech with gestures. Recipients understood and learned better from gesture-only instructions than from speech-only instructions. Gestures demonstrating action were particularly crucial, suggesting that superiority of gestures to speech may reside, at least in part, in compatibility between gesture and action.

Perspective taking promotes action understanding and learning

People often learn actions by watching others. The authors propose and test the hypothesis that perspective taking promotes encoding a hierarchical representation of an actors goals and subgoals-a key process for observational learning. Observers segmented videos of an object assembly task into coarse and fine action units. They described what happened in each unit from either the actors, their own, or another observers perspective and later performed the assembly task themselves. Participants who described the task from the actors perspective encoded actions more hierarchically during observation and learned the task better.

Putting action in perspective

Embodied approaches to cognition propose that our own actions influence our understanding of the world. Do other peoples actions also have this influence? The present studies show that perceiving another persons actions changes the way people think about objects in a scene. In Study 1, participants viewed a photograph and answered a question about the location of one object relative to another. The question either did or did not call attention to an action being performed in the scene. Studies 2 and 3 focused on whether depicting an action in a scene influenced perspective choice. Across all studies, drawing attention to action, whether verbally or pictorially, led observers to encode object locations from the actors spatial perspective. Study 4 demonstrated that the tendency to adopt the actors perspective might be mediated by motor experience.

Action learning: hierarchical organization and perspective

Many everyday actions are learned by observing others perform them. Here, we investigate an account of how the mental representations elicited by observation are transformed into action plans and how that translation can be augmented. Neuropsychological evidence suggests that the motor system is naturally aroused by observing action, implicitly mapping the actor’s body onto one’s own. Those natural processes can be augmented by manipulations that encourage coding the observed action into a goal/subgoal hierarchy and by taking the spatial perspective of the actor rather than one’s own. In a series of studies supporting this analysis, participants twice watched a video of an agent assembling an object. While watching, they pressed a button indicating when one action unit ended and another began, once for the coarsest units that made sense and once for the finest units that made sense (in counterbalanced order). In some cases, participants described or imitated what happened in each unit as they viewed; the perspective and focus of the descriptions or imitations were systematically varied. The temporal organization of the coarse and fine units provided a measure of hierarchical encoding of the action. After the segmentation task, participants were surprised by a request to perform the actions. Both hierarchical encoding and action learning were facilitated by describing or imitating the action from the actor’s perspective rather than one’s own, especially when the focus was on the actor’s hand.