Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Spectral Methods <s> Previous research has demonstrated that people’s movements can become unintentionally coordinated during interpersonal interaction. The current study sought to uncover the degree to which visual and verbal (conversation) interaction constrains and organizes the rhythmic limb movements of coactors. Two experiments were conducted in which pairs of participants completed an interpersonal puzzle task while swinging handheld pendulums with instructions that minimized intentional coordination but facilitated either visual or verbal interaction. Cross-spectral analysis revealed a higher degree of coordination for conditions in which the pairs were visually coupled. In contrast, verbal interaction alone was not found to provide a sufficient medium for unintentional coordination to occur, nor did it enhance the unintentional coordination that emerged during visual interaction. The results raise questions concerning differences between visual and verbal informational linkages during interaction and how these differences may affect interpersonal movement production and its coordination. Interpersonal interaction often results in the movements of two interactants being coordinated. The dyadically defined goals that intentionally constrain interpersonal interaction are typically responsible for the emergence of this coordination. For instance, when two people are dancing, moving a table together, or walking step-by-step with one another, each individual’s behavior is coupled to their partner’s so a shared goal can be achieved in a fluid and unperturbed manner. However, although interpersonal coordination is typically understood as intentional, highly task constrained, and sometimes overtly controlled through physical contact, it is also the case that movement coordination can occur <s> BIB001 </s> Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Spectral Methods <s> Looking To Understand: The Coupling Between Speakers’ and Listeners’ Eye Movements and its Relationship to Discourse Comprehension Daniel C. Richardson (richardson@psych.stanford.edu) Department of Psychology, Stanford University Stanford, CA 94305, USA Rick Dale (rad28@cornell.edu) Department of Psychology, Cornell University Ithaca, NY 14853, USA Abstract discussing a diagram drawn on a whiteboard, figuring out together how to do something on a computer, or talking during a movie. Uniquely poised between perception and cognition, eye movements can reveal cognitive processes such as speech planning, language comprehension, memory, mental imagery and decision making. The current experiment investigates whether the eye movements of a speaker and a listener to a visual common ground can provide insight into a discourse. While their eye movements were being recorded, participants spoke extemporaneously about a TV show whose cast members they were viewing. Later, other participants listened to these speeches while their eyes were tracked. Within this naturalistic paradigm using spontaneous speech, a number of results linking eye movements to speech comprehension, speech production and memory were replicated. More importantly, a cross- recurrence analysis demonstrated that speaker and listener eye movements were coupled, and that the strength of this relationship positively correlated with listeners’ comprehension. Just as the mental state of a single person can be reflected in patterns of eye movements, the commonality of mental states that is brought about by successful communication is mirrored in a similarity between speaker and listener’s eye movements. Eye movement Research Introduction Imagine standing in front of a painting, discussing it with a friend. As you talk, your eyes will scan across the image, moving approximately three times a second. They will be drawn by characteristics of the image itself, areas of contrast or detail, as well as features of the objects or people portrayed. Eye movements are driven both by properties of the visual world and processes in a person’s mind. Your gaze might also be influenced by what your friend is saying, what you say in reply, what is thought but not said, and where you agree and disagree. If this is so, what is the relationship between your eye movements and those of your friend? How is that relationship related to the flow of conversation between you? Language use often occurs within rich visual contexts such as this, and the interplay between linguistic processes and visual perception is of increasing interest to psycholinguists and vision researchers (Henderson & Ferreira, 2004). As yet, however, such processes have been limited to experiments that examine the eye movements of the speaker or the listener in isolation. Language use, more often than not, occurs within a richer social context as well. Direct eye contact between conversants plays an interesting, crucial role in coordinating a conversation (Bavelas, Coates, & Johnson, 2002), and in conveying various attitudes or social roles (Argyle & Cook, 1976). The focus of the current experiment, however, is cases such as those introduced at the outset, where conversants are not looking at each other, but at some visual scene that is the topic of the conversation. More common examples might be Eye movements of a speaker If a speaker is asked to describe a simple scene, they will fixate the objects in the order in which they are mentioned, around 900ms before naming them (Griffin & Bock, 2000; Meyer, Sleiderink, & Levelt, 1998). Since such pictures can be identified rapidly, it is argued that during this time speakers are not just retrieving words but selecting and planning which to use. Eye movements of a listener Eye movement research has shown that there is a tight interdependence between speech recognition and visual perception. Eye movements to potential referents for a word can provide evidence for a lexical item being recognized before the word is finished being spoken. The link between visual and linguistic processing can also be seen in eye movements that disambiguate syntactic structures (Tanenhaus, Spivey Knowlton, Eberhard, & Sedivy, 1995) and anticipate the future agents of actions (Kamide, Altmann, & Haywood, 2003). Recent studies of the eye- movements of a participant engaged in a conversation with another naive participant reveal a remarkable sensitivity to the referential domains established by the task, the visual context and the preceding conversation (Brown-Schmidt, Campana, & Tanenhaus, 2004). Qualitatively, eye movement research reveals a very close, time-locked integration between visual and linguistic processing (Tanenhaus, Magnuson, Dahan, & Chambers, 2000). Although fixation times are heavily modulated by context, as a very rough quantitative guide, research suggests that listeners will fixate an object around 400-800ms after the name onset. <s> BIB002 </s> Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Spectral Methods <s> Abstract Spontaneous social coordination has been extensively described in natural settings but so far no controlled methodological approaches have been employed that systematically advance investigations into the possible self-organized nature of bond formation and dissolution between humans. We hypothesized that, under certain contexts, spontaneous synchrony—a well-described phenomenon in biological and physical settings—could emerge spontaneously between humans as a result of information exchange. Here, a new way to quantify interpersonal interactions in real time is proposed. In a simple experimental paradigm, pairs of participants facing each other were required to actively produce actions, while provided (or not) with the vision of similar actions being performed by someone else. New indices of interpersonal coordination, inspired by the theoretical framework of coordination dynamics (based on relative phase and frequency overlap between movements of individuals forming a pair) were developed and us... <s> BIB003 </s> Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Spectral Methods <s> PCT No. PCT/KR97/00282 Sec. 371 Date Jan. 28, 1999 Sec. 102(e) Date Jan. 28, 1999 PCT Filed Dec. 29, 1997 PCT Pub. No. WO98/44532 PCT Pub. Date Oct. 8, 1998An alternating current plasma display panel with a surface discharge. The panel comprises in each pixel three parallel electrodes, one of the three parallel electrodes being an address electrode, and drive electrodes being perpendicular to them, the three parallel electrodes, the three parallel electrodes, and the drive electrode being separated by dielectric barrier ribs, geometric parameters of electrodes, discharge gaps and gas filling being determined from conditions needed for execution of a surface discharge by sustaining voltage pulses in a pixel between two extreme parallel electrodes with the address electrode arranged between them. When the discharge gap length is increased in the luminescence area, power does not increase but brightness is improved. The ratio of brightness of new/standard and the ratio of power new/standard becomes 1.1-2.3 times better. <s> BIB004 </s> Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Spectral Methods <s> The decisive role of interpersonal coordination in social interactions is well established. As human beings, we are "experts" in decoding and producing social signals, learning since our birth. Though, equipping a machine with the same abilities represents a great challenge to design socially-accepted interfaces. Assessing automatically this coordination requires selecting the most relevant features. In this paper, various audio and visual features are investigated to characterize interactional synchrony in a cooperative task. A hierarchical representation of the similarity between extracted features is proposed. The properties of time-domain (correlation coefficients) and frequency-domain (coherence) synchrony measures are confronted. The presented results support the evidence that synchrony is a multimodal phenomenon. Moreover, it can be assessed both on local (short-length windows of interaction) or global scales (entire interaction). <s> BIB005
Spectral methods constitute an interesting alternative to temporal methods when dealing with rhythmic tasks. Spectral methods measure the evolution of the relative phase between the two partners as an indication of a stable time lag between them. For instance, Oullier et al. BIB003 and Richardson et al. BIB001 ,  proposed plotting the histogram of the relative phases across the whole interaction. The stability of the interpersonal coordination between the dyadic partners was indicated by the degree of flatness of the phase distribution. Spectral methods also measure the overlap between the movement frequencies of the partners, called cross-spectral coherence BIB002 ,  , BIB005 or power spectrum overlap BIB003 , BIB004 . This quality is measured as the area of intersection between each participant's normalized spectral plots and indicates the strength of the frequency entrainment between the two partners.