**OVERVIEW**
The synchronization of physical movements between organisms is critical to exercising one’s influence on peers, initiating social learning, establishing group solidarity, and even facilitating pro-social behavior (Chartrand & Bargh, 1999; Connor, Smolker, & Bedjer’s, 2006; Lakens & Stel, 2011; van Baaren, Holland, Kawakami, & Knippenberg, 2004). Indeed, this behavioral synchrony maintains a distinct social importance, as it functions like a “social glue” that helps to solidify relationships between both human and non-human animals. Tickle-Degnen and Rosenthal (1990) further posit that this coordination is a visible manifestation of dyadic rapport development, and subsequent research supports their prediction (Bernier, Gillis, Davis, & Grahe, 1996; Grahe & Sherman, 2007; Ramseyer & Tschacher, 2011). Because situational conditions impact rapport-development between partners (Grahe & Sherman, 2007), it is plausible that subsequent displays of synchrony might be concurrently affected; accordingly, our investigation sought to explore how contextual (e.g. manipulations of cognitive load and feelings of responsibility) and participant characteristics (e.g. gender) influence this rapport / synchrony interplay.
**Study 1**
Grahe and Sherman (2007) discovered that altering perceived levels of dyadic responsibility influences communication efforts between dyad members, and rapport-building is highly dependent on effective communication (Valdesolo, Ouyang, & DeSteno, 2010). Dunbar’s dyadic power theory (2001) also suggests that an imbalance in dyadic responsibility leads to destructive communication tendencies, and consequently, possible rapport impairment; interestingly, Dunbar (2001) discovered that males reported more feelings of power and control in a dyadic discussion than females did. Using 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, this study examined if perceptions of authority and the gender-specificity of a task influenced the relationship between synchrony and rapport-building efforts.
**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. Men and women are socialized to rely on different nonverbal communication tendencies (Eagly & Wood, 1999; Hall, Carter & Horgan, 2000), and such tendencies may function to encourage or impede rapport-building.
**Study 3**
Employing a 2 (Task: Menu vs. Close Call) X 2 (Cognitive Load: High vs. Low) between-subjects design, researchers explored the effects of cognitive load and self-disclosure on rapport and consequential synchrony. Cognitive load magnifies task difficulty and automatic processing in group settings (Gilbert & Osborne, 1989; Locke, 1982), and the resulting effects might disrupt rapport-building. In addition, Bernieri, Gillis, Davis & Grahe and (1996) discovered that task types with high levels of self-disclosure increase rapport among partners.
**Study 4**
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. Previous research suggests that mutual tasks requiring partner interdependence prime high-rapport ratings between dyad members (Grahe & Sherman, 2007).
