This was said by Mother Teresa before she died. So no later than 1977.
Answer: That became a symbol of Christ — being triangular in shape it represents the trinity — and from there came the idea that the tree should be a symbol of Christ and new life," Dr Wilson said. "That's one of the main origins of the Christmas tree and bringing it into the house."
Edward Tolman's is the correct answer.
Edward Tolman was an American psychologist and a famous professor who made contributions to the Psychology studies. Through a serie of researches with rats, Edward Tolman was able to develop the Latent Learning in both animals and humans. He argued that people are constantly learning even when they don't make great effort to it. When we drive or walk the same route home everyday, we learn the location of different buildings, places, and objects. If, for some reason, we're unable of taking the route we're used to take, we will have no problem finding a different one to get home.
Stage 2 of pre-conventional development
Pre-conventional development is the area of development when someone is self-concerned. Stage 1 is when there is no difference between the right thing and not getting punished, so it has to be stage 2 of pre-conventional development.
