This paper examines Harry Harlow's landmark maternal-separation and social isolation experiments conducted on rhesus monkeys. The research demonstrated that contact comfort and companionship are more important than food and sustenance in forming healthy mother-infant attachments. Through controlled studies using cloth and wire surrogates, Harlow revealed that infant monkeys preferred physical contact with a soft cloth mother over a wire mother providing food. The findings have profound implications for understanding human child development, the effects of early social deprivation, and the importance of caregiving in institutional and family settings.
Harry Frederick Harlow was an American psychologist best known for his maternal-separation, dependency needs, and social isolation experiments on rhesus monkeys. His groundbreaking research demonstrated the importance of caregiving and companionship in social and cognitive development. Harlow conducted most of his research at the University of Wisconsin-Madison, where he worked alongside humanistic psychologist Abraham Maslow for a short period of time. Maslow was among Harlow's first doctoral students at the university, where Harlow was establishing his research program.
The fundamental purpose of Harlow's research was to determine what matters most in the relationship between mother and child: comfort and caregiving, or food and sustenance. This seemingly simple question challenged the prevailing behaviorist assumption that infants bond with their mothers primarily because mothers provide food. Through careful experimentation, Harlow would demonstrate that comfort and physical contact are far more important to healthy attachment than nutritional provision alone.
To test his hypothesis, Harlow designed an elegant experiment using two surrogate mothers made from different materials. One surrogate was constructed from wire mesh and equipped with a feeding bottle, providing nourishment but no comfort. The other surrogate was covered in soft cloth, offering comfort through tactile contact but no food. Baby rhesus monkeys were then placed in an environment where they could access both surrogates, allowing researchers to observe which the infants preferred and how much time they spent with each.
The results were striking and unambiguous. By the age of approximately three weeks, all of the monkeys were spending around 15 hours per day in contact with the cloth surrogate. In sharp contrast, no animal spent more than 1 to 2 hours in any 24-hour period on the wire surrogate, regardless of which surrogate provided food. This dramatic difference revealed that the infants' attachment was driven not by hunger satisfaction but by the need for physical comfort and security.
Harlow concluded that "contact comfort"—provided by the softness of the cloth covering—was more important than feeding in the formation of an infant rhesus monkey's attachment to its mother. This finding overturned decades of psychological theory and opened new avenues for understanding the emotional and physical needs of developing organisms. The research showed that even when food was available only from the wire mother, infant monkeys would obtain nourishment quickly and then return to the cloth mother, demonstrating that attachment bonds are formed through mechanisms beyond simple feeding associations.
"Early deprivation linked to social isolation and antisocial behavior"
The broader implications of Harlow's work extend to understanding the consequences of early social deprivation. Infants deprived of adequate maternal contact and comfort tend to isolate themselves socially and may develop antisocial personalities. This pattern has documented connections to behavioral problems later in life. Many individuals who engage in criminal behavior exhibit antisocial personality traits characterized by impulsivity and aggression. Children deprived of adequate attention and affection may resort to maladaptive behaviors—such as criminal activity—to gain recognition from peers or other people. Additionally, infants experiencing severe deprivation often develop anger and resentment that can persist into adulthood, manifesting as aggressive or antisocial conduct throughout their lives.
Harlow's landmark experiments fundamentally changed how psychologists understand infant development and the role of emotional bonding in healthy growth. By demonstrating that contact comfort supersedes feeding in importance, his research provided empirical evidence for what many have intuitively understood: that love, affection, and physical closeness are essential to raising psychologically healthy individuals. The implications of his work continue to inform childcare practices, institutional policies, and family dynamics across the world.
You’re 84% through this paper. Sign up to read the remaining 1 section.
Sign Up Now — Instant Access Already a member? Log inAlways verify citation format against your institution’s current style guide requirements.