Lm. Herman et al., Dolphins (Tursiops truncatus) comprehend the referential character of the human pointing gesture, J COM PSYCH, 113(4), 1999, pp. 347-364
The authors tested a dolphin's (Tursiops truncatus) understanding of human
manual pointing gestures to 3 distal objects located to the left of, to the
right of, or behind the dolphin. The human referred to an object through a
direct point (Pd), a cross-body point (Px), or a familiar symbolic gesture
(S). In Experiment 1, the dolphin responded correctly to 80% of Pds toward
laterally placed objects but to only 40% of Pds to the object behind. Resp
onding to objects behind improved to 88% in Experiment 2 after exaggerated
pointing was briefly instituted. Spontaneous comprehension of Pxs also was
demonstrated. 2-way combinations of these 3 to direct the dolphin to take t
he object referenced second to the object referenced first. Accuracy ranged
from 68% to 77% correct (chance = 17%). These results established that the
dolphin understood the referential character of the human manual pointing
gesture.