**Please see the files below for PDF copies of our measures.* **SHARED METHODOLOGICAL FRAMEWORK:** All four studies relied upon a protocol developed by Dr. Fabian Ramseyer (University of Bern, Switzerland). Dr. Ramseyer shared this methodology with an undergraduate research initiative (Collective Undergraduate Research Project; Grahe, 2009), and students adapted his procedure to include novel manipulations of their choosing. The paragraphs below serve as a walkthrough for parts of the procedure that all studies shared. **Pretest** Upon entering the lab, participants were asked to complete a computerized pretest before interacting with one another. This pre-task battery included the following measures: *IIP - Inventory of Interpersonal Problems (Horowitz, Alden, Wiggins, & Pincus, 2000)* - Individuals rated how much certain social problems affect them (e.g. “It is hard for me to socialize with other people”). *IRI - Interpersonal Reactivity Index (Davis, 1980)* - A blending of three different sub-scales (namely, measures of empathetic concern, perspective-taking, and fantasy) that gauged participants’ levels of empathy. *IGB - Interpersonal Goals and Boundaries* - A measure of interpersonal behavior where participants rated how accurately a given statement (for example, “I am very sensitive to other people’s feelings”) described him or her. **Dyadic Tasks** Next, participants engaged in the dyadic tasks that served as a stage for rapport-building and corresponding behavior-mirroring. Depending on the study, participants responded to either one or both of the following prompts: *Interaction 1: Menu Task* You and your interaction partner are asked to compile a five-course menu for a special dinner. Please discuss different variants of combinations of foods and drinks both of you dislike. The menu may consist of the following items: soup, starters/appetizers, main course including side dishes, cheeses, desserts, drinks. You have six minutes to complete the task. *Interaction 2: Close-Call Experience* Please describe a close call or "near-miss" situation that you had either experienced yourself, witnessed or heard about and tell each other your reactions."Close-call" and "near-miss" refer to situations where you or somebody else was very close to an accident/bad luck or other danger (e.g. sliding with your bicycle on a slipper patch). Each of you should describe at least one such situation to the other. You have a total of six minutes to discuss close-call experiences **Posttest** After each interaction, participants filled out a computerized posttest. The measures included in this post-task battery are listed below: *Measure of Familiarity* - Because these data were collected on a fairly small college campus, we took into account whether participants had known each other prior to the experiment, and if so, how “well” they knew that other person. *IOS - Inclusion of Others in Self (Aron, Aron, & Smollan, 1992)* - A pictorial-based measure that gauges perceptions of interpersonal closeness between people. *PANAS - The Positive and Negative Affect Scale (Watson, Clark, & Tellegen, 1988)* - This measure asked participants to recall the degree to which they encountered certain moods (for instance, feeling “interested” or “hostile”) during the preceding interaction. *IRQ - The Post-Interaction/Rapport Questionnaire (Bernieri, Gillis, Davis & Knee, 1994)* - Participants rated the degree to which certain rapport-based characteristics were present in the dyadic task. *FIQ - Future Interaction Questionnaire (Coyne, 1976)* - Participants reported the likelihood that they would “befriend” or “spend more time” with their partner outside of the interaction. **MOTION ENERGY ANALYSIS (MEA):** Dr. Ramseyer, in addition to the procedure listed above, also provided our lab with a ground-breaking method of coding for synchronous behavior between interactants. A majority of previous research has depended upon subjective, third-person assessments to code for movement coordination. Although this method appears to be accurate (Ambady & Rosenthal, 1991) and reliable across judges (Cappela, 1997), technological advancements now allow for more objective techniques of synchrony measurement. Accordingly, we employed a software program, Motion Energy Analysis (MEA; Rokesby & Ramseyer, 2008), to evaluate behavioral synchrony concurrent with each dyadic task. The MEA converts pixels from digital videos of the interactions into their grayscale format, ranging from 0 (true black) to 255 (true white). Each frame is then isolated and pixel hue-change between frames is calculated and conceptualized as motion-energy (ME). Examination of ME can be bounded by pre-determined “maps” or drawn-out regions of a participant’s body; cross-correlating ME between any given region from both dyad members yields synchrony scores. **STUDY IDIOSYNCRASIES:** **Study 1** This study examined if perceptions of authority and the gender-specificity of a task influenced the relationship between synchrony and rapport-building. In a 2 (Gender Specificity: Superbowl vs. Baby Shower) X 2 (Partition of Responsibility: Equal or Individual) X 3 (Dyad Makeup: Male-Male, Mixed, Female-Female) between-subjects design, researchers asked participants to complete the “Menu Task” (see above) with the finalized menu either being for an imaginary baby shower (feminine undertones) or a Super Bowl party (masculine undertones). Moreover, the experimenter manipulated perceived authority by either designating both members of the dyad, or one member in particular, as being “entirely responsible for the completion of the task”. **Study 2** Of interest to this study was how different variations of dyad sex-makeup (female-female, male-female, male-male) affect this rapport / synchrony connection. Participants engaged in both the “Menu Task” and the “Close-Call Experience” (the order of which was randomized), so two post-test scores resulted from each dyad. Because dyad sex-makeup was left free-to-vary, researchers examined far more female-female dyads than the other sex constructions. **Study 3** Here, researchers explored the effects of cognitive load and self-disclosure (as dictated by task type, since the “Close Call Experience” asked participants to explicitly self-disclose, while the “Menu-Task” did not) on rapport and consequential synchrony. In a A 2 (Task: Menu vs. Close Call) X 2 (Cognitive Load: High vs. Low) between-subjects design, participants in the “high” cognitive load condition were given an eight-digit sequence of numbers to remember during the dyadic task; they were then asked to recite the numbers once the task concluded. Subjects in the “low” cognitive load condition simply received instructions for the task directly after completion of the pretest. Paas' Cognitive Load Scale (1992) was added to the post-test battery to assess difficulties related to cognitive load. **Study 4** This study strays the most from Dr. Ramseyer’s original procedure, as it employed an interdependent puzzle task (Grahe & Sherman, 2007), rather than the Ramseyer’s conversational tasks, to prompt dyad interaction. A 3 (Partner Interdependence: None vs. Partial vs. Full) X 2 (Cognitive Load: Absent vs. Present) between-subjects design assessed the influence of partner interdependence and cognitive load on the rapport / synchrony relationship. In their completion of the puzzle, one partner was assigned the role of “the worker”, meaning he or she physically completed the task, while the other was deemed “the instructor” and verbalized instructions to the worker. Partner interdependence was manipulated with the use of either a mirror (in the “partial” interdependence condition), which forced the worker to rely more heavily on the instructor’s commands, or with a visual shield apparatus (in the “full” interdependence condition) so that the worker couldn’t view the puzzle at all. Moreover, researchers employed the same cognitive load manipulation used in Study 3, and thus participants in the “high” condition were confronted with a numeric sequence prior to engaging in the puzzle task.