Stimulation Influences Ability An outstanding and original Canadian psychologist, Donald Hebb, once took some young laboratory rats home for his daughters to play with - and play with his daughters. Later he took the rats back and tested their ability to learn the way to food in a maze. The petted rats did better than their cousins which had been kept in the usual boring cages. This was hardly rigorous research but, later, many properly designed experiments were performed in Hebb's laboratory. I mention before about the preference of domestic rats for an environment which contains a variety of objects. Young rats are energetically exploratory and playful, often having to be retrieved by their mother. Hebb's domestic researches had suggested that the resulting stimulation influences the development of ability. Source: the book "The Story of Rats" by S.A. Barnett