25 January 2011
Psych 178 – Lecture 7
The Person as a Machine
Lewin’s Theory – The person as a point in space
• Approach avoidance conflicts are also difficult to resolve: you want to buy a new car but it’s expensive. You
want to drink a milkshake but it’s fattening.
o They are stable difficult to resolve.
• Substitution: how can one goal substitute for another. When one goal is unavailable can another substitute
o You are madly in love with Mary but Mary moves to Alaska. She is no longer a feasible mate but
you do not want to choose anyone over Mary. She cannot be replaced.
o Freud thinks that this is a closed energy system and once you spend all this energy on Mary and
wanting to be with her, you have less energy to do other things.
o Lewin does not think this is true, but nonetheless this dilemma makes a tense system. This is
partially permeable and the tensions can spread. The tension can spread to Jane and she achieves
a positive valence only because you are interested in Mary. Jane now has substitute value for Mary.
(Open energy system)
o Something acquires its value because something else is unavailable. Jane is only a substitution for
Mary if she gains value because of your interest in Mary.
• If Jane got her substitute valence from Mary but if you are not interested in her then she has no
• I want to hit father but I know that there will be many negative consequences so I kick the dog instead. This
aggression is displaced from the original object and displaced and redirected to another object.
• If there is a hungry rat and there is food but there is also shock in the way. Going toward the food means
going towards the shock too. So there is force towards the food and away from the shock. Lewin says that
this is not resolvable.
o Children at the beach drop their toys in the water but the wave comes in and they run away from
• How do you get an organism to go toward a goal but then move away from it because of an aversive
reaction? How do you make this organism oscillate between the two?
o Approach gradient increases as you get towards the goal.
o Lewin wants to start the avoidance gradient below the approach gradient until a certain point where
it becomes steeper where fear becomes greater than desire.
o As the organism gets towards the food, the hunger does not really increase. However, this is not