 American Psychologist  He provided a new understanding of human behavior and development through studies of social behavior of monkeys.  His research contributions (in the areas of learning, motivation, and affection) have major relevance for general and child psychology.

Harlow's research developed  an abundant supply of primate learning tests and tasks that became standards in the field.  Harlow wanted to prove to the psychology community that primate research could contribute to the understanding of important clinical issues without having to be molecular in nature.  His theory hinged on the universal need for contact.  Harlow's famous wire/cloth "mother" monkey studies demonstrated that the need for affection created a stronger bond between mother and infant than did physical needs (food).

 In Harlow's initial experiments, infant monkeys were separated from their mothers at six to twelve hours after birth and were raised instead with substitute or "surrogate" mothers made either of heavy wire mesh or of wood covered with cloth. Both mothers were the same size, but the wire mother had no soft surfaces while the other mother was cuddly covered with foam rubber and soft terry cloth. Both mothers were also warmed by an electric light placed inside them.

 In one experiment both types of surrogates were present in the cage, but only one was equipped with a nipple from which the infant could nurse. Some infants received nourishment from the wire mother, and others were fed from the cloth mother. Even when the wire mother was the source of nourishment (and a source of warmth provided by the electric light), the infant monkey spent a greater amount of time clinging to the cloth surrogate. These results led researchers to believe the need for closeness and affection goes deeper than a need for warmth.

 These monkeys raised by the dummy mothers engaged in strange behavioral patterns later in their adult life. Some sat clutching themselves, rocking constantly back and forth; a stereotypical behavior pattern for excessive and misdirected aggression.  Normal sexual behaviors were replaced my misdirected and atypical patterns: isolate females ignored approaching normal males, while isolate males made inaccurate attempts to copulate with normal females.

 As parents, these isolate female monkeys (the "motherless mothers" as Harlow called them) were either negligent or abusive. Negligent mothers did not nurse, comfort, or protect their young, nor did they harm them. The abusive mothers violently bit or otherwise injured their babies, to the point that many of them died. Deprivation of emotional bonds to live mother monkeys (as infant monkeys) these (now adult) monkeys were unable to create a secure attachment with their own offspring.  (Principles of General Psychology, 1980, John Wiley and Sons).

Harlow's research suggested  the importance of mother/child bonding.  Not only does the child look to his/her mother for basic needs such as food, safety, and warmth, but he also needs to feel love, acceptance, and affection from the caregiver.  His findings show some long-term psychological physical effects of delinquent or inadequate attentiveness to child needs.

 Harlow also did learning research with his monkeys. His theory, "Learning to Learn", described the ability of animals to slowly learn a general rule that could then be applied to rapidly solve new problem sets.

Harlow's learning research demonstrates that animals, like humans, are able to learn to apply strategies or rules to situations to help them solve problems.