Bridgette Martin Hard

Embodied and disembodied cognition: Spatial perspective-taking

Although people can take spatial perspectives different from their own, it is widely assumed that egocentric perspectives are natural and have primacy. Two studies asked respondents to describe the spatial relations between two objects on a table in photographed scenes; in some versions, a person sitting behind the objects was either looking at or reaching for one of the objects. The mere presence of another person in a position to act on the objects induced a good proportion of respondents to describe the spatial relations from that persons point of view (Experiment 1). When the query about the spatial relations was phrased in terms of action, more respondents took the others perspective than their own (Experiment 2). The implication of action elicits spontaneous spatial perspective-taking, seemingly in the service of understanding the others actions.

Making sense of abstract events: Building event schemas

Everyday events, such as making a bed, can be segmented hierarchically, with the coarse level characterized by changes in the actor’s goals and the fine level by subgoals (Zacks, Tversky, & Iyer, 2001). Does hierarchical event perception depend on knowledge of actors’ intentions? This question was addressed by asking participants to segment films of abstract, schematic events. Films were novel or familiarized, viewed forward or backward, and simultaneously described or not. The participants interpreted familiar films as more intentional than novel films and forward films as more intentional than backward films. Regardless of experience and film direction, however, the participants identified similar event boundaries and organized them hierarchically. An analysis of the movements in each frame revealed that event segments corresponded to bursts of change in movement features, with greater bursts for coarse than for fine units. Perceiving event structure appears to enable event schemas, rather than resulting from them.

The Shape of Action

How do people understand the everyday, yet intricate, behaviors that unfold around them? In the present research, we explored this by presenting viewers with self-paced slideshows of everyday activities and recording looking times, subjective segmentation (breakpoints) into action units, and slide-to-slide physical change. A detailed comparison of the joint time courses of these variables showed that looking time and physical change were locally maximal at breakpoints and greater for higher level action units than for lower level units. Even when slideshows were scrambled, breakpoints were regarded longer and were more physically different from ordinary moments, showing that breakpoints are distinct even out of context. Breakpoints are bridges: from one action to another, from one level to another, and from perception to conception.

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.

Acoustic Packaging: Maternal Speech and Action Synchrony

The current study addressed the degree to which maternal speech and action are synchronous in interactions with infants. English-speaking mothers demonstrated the function of two toys, stacking rings and nesting cups to younger infants (6-9.5 months) and older infants (9.5-13 months). Action and speech units were identified, and speech units were coded as being ongoing action descriptions or nonaction descriptions (examples of nonaction descriptions include attention-getting utterances such as “Look!” or statements of action completion such as “Yay, we did it!”). Descriptions of ongoing actions were found to be more synchronous with the actions themselves in comparison to other types of utterances, suggesting that: 1) mothers align speech and action to provide synchronous “acoustic packaging” during action demonstrations; and 2) mothers selectively pair utterances directly related to actions with the action units themselves rather than simply aligning speech in general with actions. Our results complement past studies of acoustic packaging in two ways. First, we provide a quantitative temporal measure of the degree to which speech and action onsets and offsets are aligned. Second, we offer a semantically based analysis of the phenomenon, which we argue may be meaningful to infants known to process global semantic messages in infant-directed speech. In support of this possibility, we determined that adults were capable of classifying low-pass filtered action- and nonaction-describing utterances at rates above chance.

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.