Common ground (CG), i.e., the knowledge, beliefs and assumptions interlocutors mutually share in interaction, is fundamental to successful communication (Clark, 1996). Next to studies finding gestural ellipsis in the context of CG, an increasing number of studies has shown that speakers use co-speech gestures at the same rate (or even a higher one) when they do compared to when they do not share CG with their interlocutor (e.g. Campisi & Ozyurek, 2013; Holler & Wilkin, 2009; Holler, Tutton & Wilkin, 2011). Common ground (CG), i.e. the knowledge, beliefs and assumptions that interlocutors mutually share in interaction, is fundamental to successful communication (Clark, 1996). In contrast to studies that have found gestural ellipsis when a speaker shares CG with an interlocutor, an increasing number of studies have shown that speakers use co-speech gestures at the same rate (or even higher) when they share CG as opposed to when they do not (e.g. Campisi & Ozyurek, 2013; Holler & Wilkin, 2009; Holler, Tutton & Wilkin, 2011). There are two alternative explanations for this finding. On the one hand, it has been argued that mentally representing our addressee’s knowledge can require considerable cognitive effort (Pickering & Garrod, 2004). In combination with evidence that gesturing helps to reduce cognitive load in cognitively effortful tasks (e.g., Goldin-Meadow, 1999), one hypothesis is that gesture rate is high in CG contexts because cognitive effort involved in mentally representing CG is high. This contrasts markedly with the hypothesis that gesture rate remains high when CG exists because the gestures play an important communicative role even when they are conveying information that is mutually shared (Holler & Wilkin, 2009). There are two alternative explanations for this finding. On the one hand, it has been argued that mentally representing our addressee’s knowledge can require considerable cognitive effort (Pickering & Garrod, 2004). In combination with evidence that gesturing helps to reduce cognitive load in cognitively effortful tasks (e.g. Goldin-Meadow, 1999), one hypothesis is that gesture rate is high in CG contexts because the cognitive effort involved in mentally representing CG is high. This contrasts markedly with the hypothesis that gesture rate remains high when CG exists because gestures play an important communicative role, even when conveying information that is already mutually shared (Holler & Wilkin, 2009). The present study tested these two hypotheses by combining the manipulation of CG with a manipulation of communicative context. We used a 2(CG) x 3(communication context) between-participants design (18 participants per condition, N=108). All participants watched a short film and narrated it to their addressee. Addressees had either seen parts of the film together with the speaker (CG) or not (no- CG). In addition, we manipulated communication context by asking speakers to narrate their story either face-to-face, via an occluding screen, or into a tape-recorder, a manipulation that has been shown to affect gesture rate in no-CG contexts (Bavelas et al., 2008). If gestures produced in CG contexts are triggered by the cognitive effort of having to mentally represent CG, then social manipulations of this kind should not influence gesture rate in. If gestures conveying information already in CG are communicatively intended, however, then we would expect gesture rate to be different in the three conditions. Our results revealed a significant main effect of social context, with gesture rate being highest in the face-toface condition, followed by the screen condition, and lowest in the tape-recorder condition. Importantly, we did not find a main effect of common ground on gesture rate, and no interaction between our two factors.The present study tested these two hypotheses by combining the manipulation of CG with a manipulation of communicative context. We used a 2(CG) x 3 (communication context) between-participants design (18 participants per condition, N=108). All participants watched a short film and narrated it to their addressee. Addressees had either seen parts of the film together with the speaker (CG) or not (no-CG). In addition, we manipulated communicative context by asking speakers to narrate their story either faceto- face, via an occluding screen, or into a tape-recorder, a manipulation that has been shown to affect gesture rate in no- CG contexts (Bavelas et al., 2008). If gestures produced in CG contexts are triggered by the cognitive effort of having to mentally represent CG, then social manipulations of this kind should not influence gesture rate. However, if gestures conveying information already in CG are communicatively intended, then we would expect gesture rate to be different in the three conditions. Our results provide several insights. Firstly, they add to the growing body of evidence for maintained/high gesture rate in some common ground contexts. Secondly, they replicate effects of visual access and dialogue on gesture rate found in earlier studies manipulating social interaction. Thirdly, and most importantly, this social interaction effect affected gesture rates in both the common ground and no-common ground conditions equally. This finding is compatible with the account that gestures representing CG information are communicatively intended but not with a cognitive effort-based explanation. Our results revealed a significant main effect of communicative context, with gesture rate being highest in the face-to-face condition, followed by the screen condition, and lowest in the tape-recorder condition. Importantly, we did not find a main effect of common ground on gesture rate, and no interaction between our two factors