Results of tests investigating preferences for Edith, Eva, Pearl, Kilimi, Louis and Frek.

<p>Trends are italicised and significant results are shown in bold and underlined.</p

Behaviours recorded in instantaneous scan samples.

<p>Behaviours recorded in instantaneous scan samples.</p

Results comparing the percentage time spent displaying abnormal behaviours between music and silence.

<p>Paired T-tests were used to compare Music with Silence and “classical difference” with “pop/rock difference” were compared with Independent T-tests for Rene (N = 22), Lianne (N = 36) and Paul (N = 22).</p

Results comparing “classical difference” with “pop/rock difference”.

<p>Positive mean values indicate more of the behaviour was observed in the music period (classical or pop/rock) compared to the matched silence period; whilst negative mean values indicate more of the behaviour was observed in the silence period compared to the matched music period (classical or pop/rock).</p

Illustration of the first trial in a classical button training session.

<p>This shows the touchscreen images, associated auditory output, actions of the chimpanzees or experimenter, and timings. The downwards arrows indicates a change which is the result of the adjacent action, and is not reflected in an immediate change of visual stimulus. Training continued until the Classical music button had been successfully pressed 10 times, after which the touchscreen was turned off whilst the next training phase was loaded on the computer. If the touchscreen was not interacted with for 30 seconds during a training session, it reverted back to the green circle screen.</p

Scatterplot illustrating the mean button presses across all four groups in each of the 16 sessions.

<p>Line of best fit is shown.</p

a and b. Graphs showing a) the choices of the four possible button presses made by group C2 and b)–the percentage of total presses by group C2 per individual.

<p>Pacer, Cordova and Junie are not included in the graphs as they did not contribute any button presses.</p

a, b and c. The number of times a) Edith, b) Pearl and c) Kilimi pressed each type of button during individual testing.

<p>a, b and c. The number of times a) Edith, b) Pearl and c) Kilimi pressed each type of button during individual testing.</p

Results for paired T-tests.

<p> Tests were comparing mean proportion of scans spent engaging in Passive, Active, Socially Active, Self-grooming and Abnormal Behaviours between Music and Silence trials. Trends are italicised and significant differences are shown in bold and underlined.</p

Results of tests investigating preferences for each of the four groups.

<p>Significant results are in bold and underlined.</p