A case of hand waving: Action synchrony and person perception

While previous research has demonstrated that people’s movements can become coordinated during social interaction, little is known about the cognitive consequences of behavioral synchrony. Given intimate links between the systems that regulate perception and action, we hypothesized that the synchronization of movements during a dyadic interaction may prompt increased attention to be directed to an interaction partner, hence facilitate the information that participants glean during a social exchange. Our results supported this prediction. Incidental memories for core aspects of a brief interaction were facilitated following in-phase behavioral synchrony. Specifically, participants demonstrated enhanced memory for an interaction partner’s utterances and facial appearance. These findings underscore the importance of action perception to social cognition.     

Dynamic action units slip in speech production errors

In the past, the nature of the compositional units proposed for spoken language has largely diverged from the types of control units pursued in the domains of other skilled motor tasks. A classic source of evidence as to the units structuring speech has been patterns observed in speech errors--"slips of the tongue". The present study reports, for the first time, on kinematic data from tongue and lip movements during speech errors elicited in the laboratory using a repetition task. Our data are consistent with the hypothesis that speech production results from the assembly of dynamically defined action units--gestures--in a linguistically structured environment. The experimental results support both the presence of gestural units and the dynamical properties of these units and their coordination. This study of speech articulation shows that it is possible to develop a principled account of spoken language within a more general theory of action.     

Side by side treadmill walking reduces gait asymmetry induced by unilateral ankle weight

Asymmetric gait is a hallmark of many neurological and musculoskeletal conditions. This behavior is often the result of a decrease in the stability of interlimb coordination, and synchronization to external signals such as auditory cuing or another walking individual may be helpful for altering abnormal movement patterns. The purpose of this study was to investigate the interaction between interlimb coordination and unintentional, interpersonal synchronization of gait in healthy individuals in response to unilateral ankle loading. Fifty participants completed four trials while walking on a motorized treadmill: (1) by themselves, (2) with a partner on an adjacent treadmill, (3) by themselves with additional weight applied unilaterally to their right ankle, and (4) with both a partner and unilateral weight. As expected, the addition of unilateral weight increased asymmetry according to several spatiotemporal measures of gait, but the presence of a partner on an adjacent treadmill significantly reduced this effect. Further, the amount of unintentional, interpersonal synchronization among pairings was relatively unaffected by the addition of ankle weight to one of the partners. All pairings realized a beneficial effect on asymmetrical gait but this effect was greater for pairings that consistently synchronized unintentionally. These results suggest that side by side walking might be an effective approach for influencing bilateral coordination of gait and may hold insight for understanding gait asymmetry and interlimb movement variability.     

Temporal context in speech processing and attentional stream selection: a behavioral and neural perspective

The human capacity for processing speech is remarkable, especially given that information in speech unfolds over multiple time scales concurrently. Similarly notable is our ability to filter out of extraneous sounds and focus our attention on one conversation, epitomized by the ‘Cocktail Party’ effect. Yet, the neural mechanisms underlying on-line speech decoding and attentional stream selection are not well understood. We review findings from behavioral and neurophysiological investigations that underscore the importance of the temporal structure of speech for achieving these perceptual feats. We discuss the hypothesis that entrainment of ambient neuronal oscillations to speech’s temporal structure, across multiple time-scales, serves to facilitate its decoding and underlies the selection of an attended speech stream over other competing input. In this regard, speech decoding and attentional stream selection are examples of ‘Active Sensing’, emphasizing an interaction between proactive and predictive top-down modulation of neuronal dynamics and bottom-up sensory input.     

Movement synchrony and perceived entitativity

Movement synchrony has been theoretically linked to the emergence of a social unit. To empirically investigate whether similar movement rhythms are an antecedent of perceived entitativity, movement rhythms were experimentally manipulated in four studies. Using this novel approach, stick figures waving in synchrony were found to be rated higher on entitativity than stick figures waving in different rhythms (Study 1), and this effect was extended to interactional synchrony, where different movements are performed in the same rhythm (Study 2). Objective differences in movement rhythms are linearly related to ratings of perceived entitativity, and this relationship is partially mediated by the subjectively perceived similarity of movement rhythms (Study 3). These results also held for entitativity judgments for videotaped individuals waving rhythmically (Study 4). These results support the hypothesis that movement rhythms are an important source of information which observers use to infer the extent to which individuals are a social unit.     

Behavior Matching in Multimodal Communication Is Synchronized

A variety of theoretical frameworks predict the resemblance of behaviors between two people engaged in communication, in the form of coordination, mimicry, or alignment. However, little is known about the time course of the behavior matching, even though there is evidence that dyads synchronize oscillatory motions (e.g., postural sway). This study examined the temporal structure of nonoscillatory actions—language, facial, and gestural behaviors—produced during a route communication task. The focus was the temporal relationship between matching behaviors in the interlocutors (e.g., facial behavior in one interlocutor vs. the same facial behavior in the other interlocutor). Cross‐recurrence analysis revealed that within each category tested (language, facial, gestural), interlocutors synchronized matching behaviors, at temporal lags short enough to provide imitation of one interlocutor by the other, from one conversational turn to the next. Both social and cognitive variables predicted the degree of temporal organization. These findings suggest that the temporal structure of matching behaviors provides low‐level and low‐cost resources for human interaction.     

Rhythmic finger tapping to cosine-wave modulated metronome sequences: Evidence of subliminal entrainment

Rhythmic finger tapping was examined during synchronization to metronome sequences whose base intervals were slightly perturbed by a cosine-wave function with the period of four samples. Data were collected under perturbation levels of 1%, 3%, 5% and 7% in conjunction with base intervals of 400, 500, and 600 ms. Statistical analysis examined the relationship between the inter-response interval (IRI), inter-stimulus interval (ISI) and synchronization error (SE). It was observed that IRI and SE entrain to the periodicity of the ISI patterns even at perturbation levels close to and below the conscious auditory perception threshold. Furthermore, the similarity between the IRI and ISI increased in proportion to the perturbation level. It was also found that the relative perturbation level had more influence on the synchronization behavior than the absolute level. Finally, the observed rhythmic tracking data were modeled mathematically to examine the likelihood of three possible synchronization strategies.PsycINFO classification: 2330     

Alignment in Multimodal Interaction: An Integrative Framework

When people are engaged in social interaction, they can repeat aspects of each other’s communicative behavior, such as words or gestures. This kind of behavioral alignment has been studied across a wide range of disciplines and has been accounted for by diverging theories. In this paper, we review various operationalizations of lexical and gestural alignment. We reveal that scholars have fundamentally different takes on when and how behavior is considered to be aligned, which makes it difficult to compare findings and draw uniform conclusions. Furthermore, we show that scholars tend to focus on one particular dimension of alignment (traditionally, whether two instances of behavior overlap in form), while other dimensions remain understudied. This hampers theory testing and building, which requires a well-defined account of the factors that are central to or might enhance alignment. To capture the complex nature of alignment, we identify five key dimensions to formalize the relationship between any pair of behavior: time, sequence, meaning, form, and modality. We show how assumptions regarding the underlying mechanism of alignment (placed along the continuum of priming vs. grounding) pattern together with operationalizations in terms of the five dimensions. This integrative framework can help researchers in the field of alignment and related phenomena (including behavior matching, mimicry, entrainment, and accommodation) to formulate their hypotheses and operationalizations in a more transparent and systematic manner. The framework also enables us to discover unexplored research avenues and derive new hypotheses regarding alignment.