Harlow - Maternal Deprivation

• When was Harlow's study?

  1958/9
• What was a Harlow's aim?

  He wanted to investigate whether attachments were primarily formed through food (as explained by learning theory) or through comfort.
• What was Harlow's method?

  16 monkeys separated from their mothers immediately after birth and placed in individual cages with access to two surrogate mothers.

  1 made of wire and one covered in a soft terry towel cloth.

  They are studied for 165 days.
• What were the 4 conditions?

  1. Wire mother with milk / cloth mother without milk
  2. Wire mother without milk / cloth mother with milk
  3. Wire mother only with milk
  4. Cloth mother only with milk
• What did Harlow measure?

  1. Amount of time spent with each mother
  2. Amount of time spent feeding

  Monkeys were also frightened with a loud noise and a mechanical robot to test for mother preference during stress and they were also put in a larger cage with different objects to test their degree of exploration.
• Where were the Qualitative findings?

  1. The monkeys preferred contact with the cloth mother when given a choice, regardless whether she produced the milk. They would only go to the wire mother when hungry.
  2. Monkeys with only a wire mother had diarrhoea, a sign of stress.
  3. When frightened, the monkeys took refuge with the cloth mother in conditions where she was available.
  4. When in the larger cage, the monkeys would explore more when the cloth mother was present and would return to her more frequently.
  5. Effects were long lasting. They were either sexually abnormal or cradle their own babies.
• Where were the Quantitive findings?

  1. Infants spent up to 15 hours a day with the soft mother vs 1 hour a day with the wire mother.
  2. If time spent isolated with the surrogate mothers was less than 4 months, other monkeys could help them resume some normality.
• What was Harlow's conclusion?

  Supports the evolutionary theory of attachment (Bowlby) in that it is the sensitive response and security of the caregiver that is important, not food. Also supports the critical period.