Anna F. Smet and Richard W. Byrne 1

Anna F. Smet and Richard W. Byrne 1

Electronic supplementary materials

Authors: Anna F. Smet, Richard W. Byrne*

Title: Interpretation of human pointing by African elephants: generalisation and rationality

Journal: Animal Cognition

Affiliations: Centre for Social Learning & Cognitive Evolution,

School of Psychology and Neuroscience, University of St Andrews, Fife KY16 9JP, Scotland (UK)

Corresponding author*: Email: , Tel. +44 (0) 1334 462051, Fax +44 (0) 1334 463042

Online Resource 1: Supplementary results

We tested whether the difference in results between our study, where elephants where successful at using unsustained pointing cues (Experiment 1), and the results of Plotnik and colleagues who found that Asian elephants could not use a brief 5-second pointing cue, was due to a longer period of presentation of the unsustainedpointing cue in our study. AFS coded the duration that the pointing cue was presented to subjects for all unsustained whole-arm ipsilateral pointing trials conducted with each subject where the pointing arm was clearly visible in the video material. The mean duration of the unsustained whole-arm ipsilateral pointing cue in Experiment 1 (M = 5.74s, SE = 0.46) is comparable with the 5 s used by Plotnik et al (2013); however, in 65 trials (i.e. all data points above the line shown in Supplementary Figure 1), our subjects had extra time in which to notice the pointing signal compared to those in Plotnik et al’s study. Moreover, in 64 trials our subjects had already been able to start moving after less than 5 s, as they were judged to have seen the pointing signal by that time. We propose that this flexibility in presentation conditions, combined with the fact that their attention was attracted by the experimenter, allowed them to perform optimally.

Supplementary fig. 1 Duration in seconds of the pointing cue onall unsustained whole-arm ipsilateral pointing trials for each subject (Coco: M = 6.20, SE = 0.59; Doji: M = 4.47, SE = 0.56; Jake: M = 4.7, SE = 0.53; Jock: M = 7.35, SE = 0.73; Jumbo: M = 6.15, SE = 0.76; Malasha: M = 4.27, SE = 0.41; Tendai: M = 7.65, SE = 0.99; Tembi: M = 5.16, SE = 0.64).

Supplementary fig. 2 The number of correct and incorrect first and last trials for each condition out of a total of the 8 subjectsa. Sustained whole-arm ipsilateral pointing, b. Unsustained whole-arm ipsilateral pointing, c. Sustained whole-arm cross-body pointing, d. Unsustained whole-arm cross-body pointing.

Supplementary fig. 3 The number of correct and incorrect first and last trials for each condition out of a total of the 8 subjects. a. ‘Irrational’ leg point, b. ‘Rational’ leg point, c. Whole-arm ipsilateral point, d. Control condition.