The Harlow experiment and maternal deprivation: substituting for the mother

A curious experiment with monkeys 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: everyone has his or her 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 a topic that is also much addressed by psychology: the way in which interpersonal relationships change us.

The prevailing paradigms of the first half of the twentieth century in psychology, which were psychodynamics born with Sigmund Freud and behaviorism advocated by B. F. Skinner, held the idea that the foundation of affection between mothers and their young children is nurturing 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 engage in affectionate behaviors thanks to the need of the former to be fed. Just after birth, the main role of mothers was to provide nourishment for their offspring.

However, psychologists John Bowlby and, later, Harry Harlow, struck a blow against this theory. It is thanks to them that we now know that affection in its purest and most literal sense is a fundamental need of children. In particular, Harry Harlow's monkey experiment on maternal deprivation is a case in point.

Precedent: Bowlby and attachment theory.

In the mid-twentieth century, an English psychiatrist and psychologist named John Bowlby conducted a series of investigations framed in what is known as attachment theory. This is a framework of 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 is of special importance.

The reason for this interest in the early stages of bonding is simple: it is assumed that the way in which infants form close, close and affectionate relationships with their babies during the first months of the infant's life is of great importance.The reason for this interest in the early stages of attachment formation is simple: it is assumed that the way in which infants form close, close, and affectionate relationships with others will influence their development into adulthood and have a possibly lifelong impact on a number of their psychological characteristics.

Bowlby's research

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

In part, this was based on his beliefs: Bowlby took an evolutionary approach, and advocated the idea that both mothers and newborns express genes specially selected to cause both to form a strong emotional bond. That is, he believed that the establishment of maternal attachment was genetically programmed, or at least a part of it. In addition, he argued that the strongest bond that any person can establish is the one based on the relationship he had with his mother during the first years of life.

This phenomenon, which he called monotropywas not consolidated if this exchange of affectionate gestures accompanied by physical contact (classically, during breastfeeding) took place after the baby's second year of life, and not before. In other words, the maternal deprivationthe absence of regular contact with an affectionate mother during the first months of life, was very harmful because it went against what our genetics would have programmed us for.

What did these studies consist of?

Bowlby also drew 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 because of World War II, Bowlby found significant evidence that youngsters who had experienced maternal deprivation from living in orphanages tended to be intellectually retarded and to have problems successfully managing both their emotions and situations in which they had to relate to others.

In a similar investigation, he observed that among children who had been confined for several months in a sanatorium to treat their tuberculosis before the age of 4, had a markedly passive attitude and became angry much more easily than other youngsters. than other youngsters.

From that point on, Bowlby continued to find data that reinforced his theory. He concluded that maternal deprivation tended to generate in young people a clinical picture characterized by emotional detachment from other people. People who had not been able to form an intimate attachment bond with their mothers during their early years were unable to empathize with others, because they they had not had the opportunity to connect emotionally with someone during the stage when they had been sensitive to this type of 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 so, he conducted an experiment with rhesus monkeys that by today's ethical standards would be unfeasible because of the cruelty involved.

What Harlow did was, basically, to separate some macaque cubs from their mothers and to observe how their maternal deprivation was expressed. But he did not limit himself to passive observation; he introduced into this research an element that would make it easier to know what the macaque cubs were feeling. 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 cubs into cages, a space they were to share with two artifacts. One was a wire frame with a full bottle built into it, and the other was a figure similar to an adult macaque, covered with soft plush, but without a bottle.. Both objects, in their own way, simulated a mother, although the nature of what they could offer the offspring was very different.

In this way, Harlow wanted to test not only Bowlby's ideas, but also a different hypothesis: that of conditional love. conditional love. According to the latter, offspring relate to their mothers basically because of the food they provide, which is objectively the resource with the greatest short-term utility from a rational and "economistic" point of view.

What was discovered

The result proved Bowlby right. The infants showed a clear tendency to be attached to the plush doll, despite the fact that it did not provide food. The attachment to this object was much more noticeable than the attachment to the structure with the bottle, which was in favor of the idea that it is the intimate bond between mother and offspring that is really important, and not the simple food.

In fact, this relationship was even noticeable in the way the hatchlings explored the environment. The plush doll seemed to provide a sense of security that was crucial for the young macaques to undertake certain tasks on their own initiative, and they even hugged it more tightly when they were afraid. At times when stressful changes in the environment were introduced, the cubs would run to hug the soft toy. And, when the animals were separated from this plush artifact, they showed signs of desperation and fear, screaming and searching all the time for the protective figure. When the plush doll was brought back within reach, they recovered, although they remained defensive in case they lost sight of this artificial mother again.

Triggering isolation in monkeys

The plush doll and bottle experiment was of dubious morality, but Harlow went further by worsening the living conditions of some macaques. He did this by confining the young of this animal species in enclosed spaces, keeping them isolated from any kind of social or, in general, sensory stimuli.

In these isolation cages there was only a drinking trough, a feeding trough, which was a total deconstruction of the concept of "mother" according to behaviorists and Freudians. In addition, a mirror was incorporated in this space, thanks to which one could 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 for up to a year.

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

Neglectful mothers... or even worse

When Harry Harlow decided to study the maternal behavior of macaques that had been subjected to isolation, he encountered the problem that these female monkeys never became pregnant. He used a structure ("the rape rack") in which the females were restrained with leashes, forcing them to be impregnated.

Subsequent observations showed that these females not only did not perform the typical tasks of a mother of their species, ignoring their offspring most of the time, but sometimes even mutilated their 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 John Bowlby's research and Harry Harlow's experiments are very much taken into account today, even though the latter are also a case of clear animal torture and, because of their ethical implications, have received much attention. have been strongly criticized for their ethical implications..

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 imprint that is difficult to erase in adult life.