Harlow’s Experiment And Maternal Deprivation: Replacing The Mother

A curious experiment with monkeys that gives us an explanation for a psychological phenomenon.

When talking about psychology, many people may think  of personality traits ,  mental disorders, or  cognitive biases. In short, elements that we can relate to a single person: each one has their level of intelligence, the presence or absence of a diagnosed disorder, or a propensity to fall into certain delusions of the mind. However, there is an issue that is also widely addressed by psychology: the way in which interpersonal relationships change us. 

The prevailing paradigms in the first half of the 20th century in psychology, which were the psychodynamics born with Sigmund Freud and the behaviorism defended by BF Skinner, supported the idea that the foundation of affection between mothers and their young children is feeding and, more specifically, breastfeeding. In their own way, each of these two psychological currents so different from each other in most of their approaches proposed the same idea: that babies and mothers began to get involved in affective behaviors thanks to the need of the former to be fed. Right after birth, the main role of mothers was to provide food for their offspring. 

However, psychologists John Bowlby and, later, Harry Harlow, struck a heavy blow against this theory. It is thanks to them that today we know that affection in its purest and most literal sense is a fundamental need of boys and girls. In particular, Harry Harlow’s monkey experiment on maternal deprivation is an example of this.

The precedent: Bowlby and attachment theory

In the middle of the 20th century, an English psychiatrist and psychologist named John Bowlby carried out a series of investigations framed in what is known as attachment theory. This is a framework for debate in which the psychological phenomena behind our way of establishing affective bonds with other beings are explored  , and in it the way in which fathers and mothers relate to their babies during the first months of the latter’s life.

The reason for this interest in the early stages of bonding is simple: it is assumed that the way in which youngsters build continuous, close, and loving relationships with others will influence their development into adulthood and have an impact, possibly for life, in several of its psychological characteristics.

Bowlby’s investigations

Through several studies, John Bowlby concluded that the fact that each baby has regular maternal affection is one of the most important needs for its proper growth.

In part, this was based on his beliefs: Bowlby took an  evolutionary approach, advocating the idea that specially selected genes are expressed in both mothers and newborns to make the two form a strong emotional bond. That is, she believed that the establishment of maternal attachment was genetically programmed, or at least a part of it. In addition, she argued that the strongest bond that anyone can establish is the one based on the relationship she had with her mother during the first years of life.

This phenomenon, which he called monotropia , could not be consolidated if this exchange of affectionate gestures accompanied by physical contact (classically, during breastfeeding) occurred after the baby’s second year of life, and not before. In other words, maternal deprivation , the absence of regular contact with a mother that would provide affection during the first months of life, was very harmful because it went against what our genetics would have programmed us to do.

What did these studies consist of?

Bowlby also relied on empirical data. In this sense, he found some data that reinforced his theory. For example, through research commissioned by the World Health Organization on children separated from their families by World War II, Bowlby found significant evidence that young people who had experienced maternal deprivation due to living in Orphanages tended to present  intellectual retardation and problems managing successfully both their emotions and the situations in which they had to interact with other people.

In a similar investigation, he observed that among children who had been confined for several months in a sanatorium to treat their tuberculosis before reaching the age of 4, they were markedly passive and raged much more easily than other young people.

From that point on, Bowlby continued to find data that reinforced his theory. She concluded that maternal deprivation tended to generate in young people a clinical picture characterized by emotional detachment towards other people. People who had not been able to form an intimate bond with their mothers during their early years were unable to empathize with others, because they had not had the opportunity to connect emotionally with someone during the stage in which they had been sensitive to this type learning.

Harry Harlow and the Rhesus monkey experiment

Harry Harlow was an American psychologist who during the 1960s set out to study Bowlby’s theory of attachment and maternal deprivation in the laboratory. To do this, he conducted an experiment with  Rhesus monkeys that under current ethical standards would be unfeasible due to the cruelty involved.

What Harlow did was basically separate some baby macaques from their mothers and observe how their maternal deprivation expressed itself. But he did not limit himself to passively observing, but introduced an element into this research with which it would be easier to know what the baby macaques felt. This element was the dilemma of choosing between something like physical contact related to affection and warmth, or food.

Substituting for the mother

Harlow introduced these young into cages, a space that they had to share with two artifacts. One was a wire frame with a full bottle attached, and the other was a figure similar to an adult macaque, covered with soft fleece, but no bottle. Both objects, in their own way, pretended to be a mother, although the nature of what they could offer the child was very different.

In this way, Harlow wanted to test not only Bowlby’s ideas, but also a different hypothesis: that of conditional love . According to the latter, the offspring are related to their mothers basically by the food they provide, which is objectively the resource with the greatest short-term utility from a rational and “economistic” perspective.

What was discovered

The result proved Bowlby right. The hatchlings showed a clear tendency to cling to the plush doll, despite not providing food.  The attachment to this object was much more noticeable than that professed to the structure with the bottle, which was in favor of the idea that it is the intimate bond between mothers and babies that is really important, and not simple food.

In fact, this relationship was noticeable even in the way the hatchlings explored the environment. The plush doll seemed to provide a sense of security that was decisive for the little macaques to decide to undertake certain tasks on their own initiative and they hugged it even more tightly when they were afraid. At times when there was a change in the environment that generated stress, the pups ran to hug the soft doll. And, when the animals were separated from this plush artifact, they showed signs of despair and fear, screaming and searching all the time for the protective figure. When the plush doll was brought back within reach, they recovered, though they remained on the defensive in case this artificial mother was lost again.

Causing isolation in monkeys

The stuffed animal and bottle experiment was of dubious morality, but Harlow went further by worsening living conditions for some macaques. It did so by confining the young of this animal species in closed spaces, keeping them isolated from any type of social stimulus or, in general, sensorial. 

In these isolation cages there was only a trough, a trough, which was a total deconstruction of the concept of “mother” according to behaviorists and Freudians. In addition, a mirror had been incorporated into this space, thanks to which it was possible to see what the macaque was doing but the macaque could not see its observers. Some of these monkeys remained in this sensory isolation for a month, while others stayed in their cage for several months; some, up to a year.

The monkeys exposed to this type of experience already showed evident alterations in their behavior after having spent 30 days in the cage, but those that remained a full year were left in a state of total passivity (related to catatonia) and indifference towards the others from which they did not recover. The vast majority ended up developing sociability and attachment problems when they reached adulthood, they were not interested in finding a partner or having children, some did not even eat and ended up dying.

Negligent mothers … or worse

When Harry Harlow decided to study the maternal behavior of macaques who had been isolated, he found the problem that these female monkeys did not get pregnant. To do this he used a structure (“the rape colt”) in which the females were fixed with straps, forcing them to be fertilized. 

Subsequent observations showed that these females not only did not perform the typical tasks of a mother of their species, ignoring her young for most of the time, but also occasionally mutilated her young. All this, in principle, because of maternal deprivation, but also because of social isolation, during the first months of life.

Conclusions: the importance of attachment

Both the investigations of John Bowlby and the experiments of Harry Harlow are currently very taken into account, despite the fact that the latter are also a case of clear torture of animals, and for their ethical implications they have received strong criticism.  

Both experiences led to similar ideas: the effects of the absence of social interactions that go beyond the most immediate biological needs and that are linked to affective behavior during the early stages of life tend to leave a very serious and difficult imprint. erase in adult life.

Add a Comment

Your email address will not be published. Required fields are marked *