542 Exp Brain Res (2011) 211:531–545 Fig. 6 Reaction times and linear ﬁts for both attention conditions in experiment 3. Left Preceding trial showed ﬁrst-hand picture from the ﬁrst-person perspective. Right Preceding trial showed ﬁrst-hand picture from the third-person perspective. The single-attention condition is depicted in grey (squares), the joint-attention condition in black (triangles). The linear trend line for the single condition is ﬂattened in the joint-attention condition following 3rd PP trials [t(20) = 2.3, p \ .05], but not following 1st PP trials [t(20) \ 1], as reﬂected in a two-way interaction of atten- tion and preceding trial [F(1, 20) = 4.5, p \ .05]. Attention condition [F(1, 20) = 1.3, p = .27] and pre- ceding trial [F(1, 20) = 1.5, p = .23] did not affect inter- cepts. The two-way interaction of preceding trial and attention was not signiﬁcant [F(1, 20) = 2.7, p = .12], as RTs in the joint condition were only marginally faster when the preceding trial showed the initial hand picture from a third-person perspective [t(20) = 2.1, p = .058] as com- pared to no effect when the preceding trial showed the initial hand picture from a ﬁrst-person perspective [t(20) \ 1]. Errors Error rates increased with increasing rotation [t(20) = 6.1, p \ .001]. No effect of attention or preceding trial on slopes was present in error rates [ts(20) \ 1]. Intercepts were not signiﬁcantly affected by preceding trial [F(1, 20) = 1.5, p = .25] or by attention [F(1, 20) \ 1], nor was there a signiﬁcant interaction [F(1, 20) \ 1]. Discussion 123 In this experiment, we manipulated the degree to which the directly preceding trial primed an allocentric rather than an depicted in grey, R2 = .92 for trials following ﬁrst-person perspective trials (left) and R2 = .97 following third-person perspective trials (right). The linear trend line for the joint condition is shown in black, R2 = .93 following ﬁrst-person perspective and R2 = .93 following third-person perspective trials egocentric frame of reference. The initial hand picture of the preceding trial could either be seen from the ﬁrst-per- son perspective of the participant or from the ﬁrst-person perspective of the task partner. As in the previous experi- ments, we found that joint attention led to a ﬂattening of the rotation–performance curve. However, this effect was only present following trials that primed an allocentric reference frame. When an allocentric perspective was primed in the previous trial, joint attention in the sub- sequent trial triggered a switch from an egocentric to an allocentric reference frame. These ﬁndings corroborate our interpretation of the joint-attention effect in terms of a change in reference frame. Importantly, priming an allo- centric reference frame alone cannot explain the observed effect, as the ﬂattening of the rotation–performance curve occurred speciﬁcally on joint-attention trials. Contrary to experiments 1 and 2, the effect of attention on the slope of the rotation curve did not reach signiﬁcance in this experiment when trials where the initial hand was depicted from a ﬁrst and a third-person perspective were combined. Re-analyses of experiments 1 and 2 conﬁrmed that the joint-attention effect was due to responses fol- lowing trials that depicted the initial hand from a third- person perspective, while the effect was absent when the preceding trial showed the initial hand from the partici- pant’s own perspective. Thus, the only difference between the results of experiment 3 and experiments 1 and 2