Bwtn what is determined by nature vs. nurture: maturation--refers to biologically determined changes that follow an orderly sequence-- puberty--occurs diff. First, to say how important a role unconscious plays in human behaviour. In order to be scientific phyc needs to look at observable behaviour to look at probabilities that these are true theories. First to use psychotherapy as a real type of therapy. Treatment of disorders through talking-- respond better that to drugs or surgery. First 5 years of our experiences the most important. Thought personality built in first 5 years of lives. Today, most agree 5 years very important: 5. Certain period/window to develop vision in cats we know: b. Critical periods of vulnerability--where we don"t want any certain type of stimulation ie: esp. In womb: some refer to this as sensitive period , example: genie, a case of neglect. Daughter lived in a closet and nobody spoke to her. When genie was discovered she was below physical development.