Using the Aesop's Fable Paradigm to Investigate Causal Understanding of Water Displacement by New Caledonian Crows
Mean proportion of choices made to the correct option, over 20 trials, in each experiment. (1: Sand v Water, 2: Sinking v Floating, 3: Solid v Hollow, 4: Narrow v Wide, 5: High v Low water levels, 6: U-tube.) Error bars are ±2 SE. * = significantly different from chance (binomial tests, p<0.001).