Rhesus Monkey Study (Harlow)

• Aim: to investigate whether contact comfort or the provision of food is more important when forming infant-mother attachment in rhesus monkeys
• Method: Observational and experimental study of eight newborn rhesus monkeys raised in a laboratory.
• Materials: included surrogate monkey mothers made from a rubber-covered block of wood covered in cotton terry cloth and surrogate monkey mothers made from wire mesh, milk bottles, and cages.
• Design: the IV was whether the milk bottle was attached to the cloth covered or wire-mesh surrogate mother and the DV was the time the monkeys spent on the surrogates.
• Procedure: The newborn monkeys were placed in separate cages, each containing two surrogate monkey mothers; one made from cloth, the other from wire mesh. Four cages had a milk bottle attached to the cloth-covered surrogate, the other four cages had a milk bottle attached to the wire mesh surrogate. The time each monkey spent holding onto each surrogate in their cage was timed.
• Replacement: Harlow possibly could have considered alternatives; however, monkeys are most related to humans as mammals, and it is more humane to use animals rather than humans. No other method could have been used to achieve the purpose of the study without the use of animals.
• Reduction: Harlow is responsible for involving the smallest number of animals necessary. He could have used four instead of eight monkeys, which would still achieve the purpose of the study and provide information.
• Refinement: Harlow is obligated to support and safeguard the well-being of the monkeys, but he failed to do so. He failed to use methods that would minimise the potential pain and distress in the baby monkeys.
• 3 months of the monkeys being isolated: reversible, suffered no long-term effects, and within weeks were interacting in a socially appropriate manner.
• 6 months of monkeys in isolation: They developed normal social behaviours although it took them much longer to recover.
• 12 months of monkeys in isolation: unfortunately, they never recovered from the effects of deprivation.
• Harlow found that the baby monkeys spent more time on the cloth covered surrogate mother than the wire surrogate.
• The monkeys who were provided with a cloth surrogate providing milk, spent almost no time on the wire surrogate as it offered neither food nor comfort.
• The monkeys who shared their cage with a cloth surrogate mother and a wire surrogate that had a milk bottle attached spent the minimum time required to feed from the wire surrogate and spent 16 hours per day clinging on to the cloth-covered mother from the age of 16 days.
• Harlow's research supported Bowlby's maternal deprivation hypothesis. Monkeys reared apart from their mothers suffered social and emotional difficulties later in life. As these monkeys never formed an attachment with their mother, they grew to become aggressive and exhibited problems interacting with other monkeys.