| Psychology as the science which studies thoughts, | | | | generations of rats were making an average of only |
| behavior, soul and emotions is closely connected with | | | | 20 errors each. McDougall concluded this to be |
| other sciences. | | | | evidence for the inheritance of acquired characteristics, |
| Biology takes the primary place in this connection as | | | | but his conclusion was extremely controversial and |
| physiological aspects are closely linked to many | | | | flew in the face of the orthodox theory of inheritance |
| psychological concepts. In the 1920s McDougall, a | | | | based on Mendelian genetics because the control |
| Harvard psychologist, began a series of experiments | | | | animals also learned the behavior without ever being |
| designed to determine if information and abilities | | | | exposed to it! Some of the leading biologists of the |
| learned and acquired by parents could be inherited and | | | | time subjected his experiments to critical scrutiny, but |
| passed to future generations through the genes. In his | | | | they were unable to find any significant procedural |
| experiments McDougall placed white rats, one at a | | | | flaws in his experiment. When they suggested that |
| time, in a tank of water from which they could only | | | | McDougall must have been breeding from the more |
| escape by swimming to one of two gangways and | | | | intelligent rats in each generation he designed a new |
| climbing up. One gangway was brightly lit and the other | | | | experiment in which he selected only the most stupid |
| was not. They received an electric shock if they | | | | rats in each generation as the parents of the next. |
| escaped by the illuminated gangway. McDougall | | | | Thus, by our conventional view of genetics, |
| recorded the number of trials required to learn that | | | | subsequent generations should have learned more and |
| they could always escape from the unlit gangway. | | | | more slowly. However, the reverse occurred. After 22 |
| The first generation of rats received an average of | | | | generations, the rats were learning 10 times faster than |
| over 160 shocks each before learning to avoid the | | | | the first generation of “stupid” |
| illuminated gangway. Each successive generation | | | | ancestors. |
| learned quicker than the previous one until, after 30 | | | | |