Exp Brain Res (2011) 211:531–545 Experiment 1 This experiment investigated whether engaging in joint attention from different spatial perspectives leads partici- pants to adopt an allocentric reference frame. Methods Participants Thirteen pairs of undergraduate students (mean age 20.6 years; 18 women; 22 right-handed) participated in the experiment and received course credits or payment for their participation. They were fellow students or friends. All of them reported normal or corrected-to-normal vision and signed informed consent prior to the experiment. Stimuli and procedure Participants were tested in same-sex pairs and were seated at opposite sides of a table (see Fig. 1). In between them was a 17-in TFT monitor that was ﬁxed to the table so that the screen faced the ceiling. The viewing distance to the monitor was 70 cm. Ambient light was kept at a constant level. 533 Each trial started with the presentation of a tone (900 Hz) presented for 100 ms (see Fig. 1). This tone cued the participants to open their eyes and to look at each other. After 1,500 ms, one of three tones appeared together with a ﬁxation cross (size 0.8 visual angle, presented in the centre of the screen). A 400-Hz tone indicated that it was participant A’s turn to perform the subsequent mental rotation task (and participant B’s turn to close the eyes). A 1,400-Hz tone signalled that it was B’s turn (A closing the eyes). A 900-Hz tone indicated that both participants should attend to the screen and perform the subsequent mental rotation task. In the mental rotation task, participants saw two sub- sequent pictures of hands. They were instructed to indicate whether or not the second picture depicted the same hand as the initial picture (e.g. right hand when the initial picture also depicted a right hand versus left hand when the initial picture depicted a right hand). The initial hand picture always showed a right hand. The ﬁrst picture was shown 1,500 ms after the tone, indicating whose turn it was and was presented for 700 ms. After 300 ms, the second-hand stimulus appeared until participants’ responses were recorded, thereby not exceeding 4,000 ms. There was a 500-ms inter-trial interval after the response. Stimuli of the rotation task consisted of one photograph of a female hand Fig. 1 a Schematic drawing of the experimental setting. Two people were sitting opposite each other with a ﬂat screen in between them. Both of them responded pressing keys with their right hand. Both participants placed their left hand under the table. Each participant’s right hand was hidden inside a box. b Sequence of events on each trial 123