The Influence of "Nature" Versus "Nurture"

When we breed a horse and a donkey we get a mule and the reason for this is nothing but heredity. We get two closely related people, give them a typing training and then interpret. We find their differences in skill are primarily due to training. In these two situations, both heredity and environment are involved.

This example represents most of what we are and we do. It has been shown that two seeds of a certain variety planted in the sunshine will grow up to be alike, but if one is planted in the shade it will grow up to be different. Hence, it may sometimes take a given environment to bring out hereditary similarity or differences.

From many studies of various kind of samples on the heredity-environment question, comes the conclusion that behavior will not develop properly unless the organism is able to interact normally with its environment. At any given time, an individual reflects his own genetic structure, which has in turn been influenced by a range of environments throughout his life span. Out of the product of heredity and environment come both our individuality and our individual differences. If a person with high heredity potential is placed in a poor environment, his measured ability will probably be low. If hereditary potential is low, even the best environment will have its limitations in taking the person ahead.

When we turn to animals which have off-springs in litters, we are able to do control studies on the nature-nurture problem. For example, two each of four different breeds of dogs-Shetland sheep dogs, Basenjis, fox terriers, and beagles- were reared differently. One dog of each pair was given strict discipline, the other was raised indulgently. The environments were thus different, but each pair being litter mate was similar in heredity. When each animal was eight weeks old, it was given an obedience test:

Each dog was told not to eat the bowl of food placed in front of it until it was given signal to do so. Results showed that the Shetlands stayed strictly away from the food after being spanked for approaching it, whether they had been trained with strict discipline or indulgently. The Basenjis both ate immediately even though punished. The terriers and beagles divided into two groups according to training: the disciplined pups stayed away from the food ten minutes or more after punishment, while the indulged ones ate within a short period of time. Hence, we see that the Shetlands and Basenjis responded more to "nature" and the terriers and Beagles to "nurture". Nature and nurture may work together, but one of them may play a larger role than the other in producing some given behavior.