Darwin noted that many animals rarely make noises, even when in painbut under extreme circumstances they vocalize in response to pain and fear. In some cases the explanations given seem far-fetched, or simpler ones appear to be overlooked.
Comparatively few human expressions, on the other hand, can be distinctly recognised in animals, that of sneering by raising the upper lip on one side, and thus showing the canine teeth, being one of the most curious.
She now stands upright with her back slightly arched, which makes the hair appear rather rough, but it does not bristle; her tail, instead of being extended and lashed from side to side, is held quite stiff and per- 57 -pendicularly upwards; her ears are erect and pointed; her mouth is closed; and she rubs against her master with a purr instead of a growl.
But this seems very unsatisfactory. The experiment is described as if all this were really done by reflex action; but, if so, then what need have we of consciousness in animals at all, and why may not all their motions and actions during life be so produced?
A friend told Darwin that when he rubbed his horse's neck, the horse stuck its head out, uncovered its teeth and moved its jaws, just as if it were nibbling another horse's neck. Darwin, I cannot see the necessity for them here. When a dog approaches a strange dog or man in a savage or hostile frame of mind he walks upright and very stiffly; his head is slightly raised, or not much lowered; the tail is held erect and quite rigid; the hairs bristle, especially alon the neck and back; the pricked ears are directed forwards, and the eyes have a fiked stare [ Ekman offers five reasons.
The habits and ideas of infancy seem to be completely lost in adult life, and to be replaced by others widely different; and it seems hardly likely that they should persist so strongly in one or two isolated instances without leaving more frequent and less equivocal traces behind them.
Great confusion of mind often accompanies blushing, and is supposed to be caused by it.
This was always a great disappointment to the dog, as he did not know whether I should continue my walk; and the instantaneous and complete change of expression which came over him as soon as my body swerved in the least towards the path and I sometimes tried this as an experiment was laughable.