EARLY STAGES OF MENTAL DEVELOPMENT 49 
chapter on “ Fear in Birds” in his ‘ Naturalist in La Plata,” 
and concludes that: fear of particular enemies is, in nearly all 
cases, the result of experience individually acquired. I have 
found that pheasants, partridges, plovers, domestic chicks, and 
other young birds, hatched in an incubator, show no signs of 
fear in the presence of dog or cat, so long as the animal is not 
aggressive. It should be mentioned, however, that Miss M. 
Hunt * asserts that chicks do show inherited fear of the cat. Dr. 
Thorndike’s t observations, on the other hand, support my own, 
which I have since repeated with the same results. Neither 
birds nor small mammals show any signs of fear of stealthily 
moving snakes. My fox terrier smelt, nose to nose, a young 
lamb which was lying alone ina field. I was close at hand, and 
could detect no indication of alarm on the part of the lamb till 
the mother came running up in great excitement. Then the 
lamb ran off to her dam. Whenever opportunity has arisen, 
I have introduced young kittens to my fox terrier, and have 
never seen any sign of inherited fear. He was a great hunter 
of strange cats, but was trained to behave politely to all 
birds and beasts within the precincts of my study. It is true 
that he was on good terms, or at least terms of permissive 
neutrality, with the kittens’ mother. And it may be said that 
this was inherited ; but such an argument cannot apply in the 
case of pheasant or lamb. 
Here, as throughout our study of animal behaviour in its 
conscious aspect, we have not only to conduct observations 
with due care, but to draw inferences with due caution. 
Douglas Spalding described how newly hatched turkeys 
showed signs of alarm at the cry of a hawk ; and he inferred 
that, since this sound was quite new to their individual expe- 
rience, the alarm was due to the inheritance of ancestral 
experience of hawks. But since young birds show signs of 
alarm at any sudden and unaccustomed sound—a sneeze, the 
noise of a toy horn, a loud violin note, and so forth—the safer 
inference seems to be that they may be frightened by strange 
* American Journal of Psychology, vol. ix., No. 1. 
+ Psychological Review, vol. vi, No. 3. 
