Fig 1.
Experiment 1A: Sinking vs. floating and Experiment 1B: Solid vs. hollow apparatus.
Fig 2.
Experiment 2: Functionality vs. reward apparatus.
Table 1.
Crows: initial preferences for sinking and solid objects.
Children: Group 1 = initial preference for sinking and hollow objects; Group 2 = trained preference for floating, and no preference for solid vs. hollow objects post-testing. Binomial tests, significant p-values highlighted in bold. NS = not significant. Figures indicate number of items chosen over all trials.
Fig 3.
Total percentage correct choices across each subject group for trial 1, trials 1–5 and trials 1–20 for Experiment 1A: Sinking vs. floating objects.
Crows: A comparison of the correct choices made by crows that were trained to develop a preference for the floating object before the Aesop’s Fable test (present study) and crows without this experience, tested in previous experiments [5, 6]. Children: A comparison of the children tested in present study, by age group, and children tested in a previous experiment [10]. In [10] children received 5 trials only. Binomial tests: NS = non-significant, * = significant (p<0.05).
Table 2.
Experiment 1A results: Sinking vs. floating objects.
Crows: trained pre-test preference for floating objects in crows in present study (n = 5) vs. [5, 6] crows (data combined, n = 12). Children in present study (n = 29) vs. [10] children (aged 5–9 years and tested in 5 trials only, n = 51). Binomial tests: NS = not significant. Significant p-values highlighted in bold.
Fig 4.
Total percentage correct choices across each subject group for trial 1, trials 1–5 and trials 1–20 for Experiment 1B: Hollow vs. solid objects.
Binomial tests: NS = non-significant, * = significant (p<0.05).
Table 3.
Experiment 1B results: Solid vs. hollow objects.
Crows: trained pre-test preference for floating objects in crows in present study (n = 5) vs. [5, 6] crows (n = 12). Children in present study (n = 33)–no other children previously tested in hollow vs. solid. Binomial tests: NS = not significant. Significant p-values highlighted in bold.