Harlow's experiment and maternal deprivation

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 own 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 widely addressed by psychology: the way in which interpersonal relationships change us.

The prevailing paradigms in the first half of the twentieth century in psychology, which were psychodynamics born with Sigmund Freud and the behaviorism advocated by B. F. Skinner, held the idea that the foundation of affection between mothers and their young children is food 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 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 children. 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 he carried out a series of investigations framed in what is known as attachment theory. This is a framework for discussion in which the psychological phenomena that are behind our way of establishing affective ties with other beings, and in it has a special importance of how fathers and mothers relate to their babies during the first months of life. the latter.

The reason for this interest in the early stages of bonding is simple: It is assumed that the way in which the little ones strengthen continuous relationships, close and with displays of affection with others will influence their development into adulthood and will have an impact, possibly for life, on several of their psychological characteristics.

Bowlby's investigations

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

In part, this was based on his beliefs: Bowlby adopted a evolutionary approach, and defended the idea that specially selected genes are expressed in both mothers and newborns to make both 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 that is based on the relationship he had with his mother during the first years of life.

This phenomenon, which he gave to call monotropy, it was not consolidated if this exchange of affectionate gestures accompanied by physical contact (classically, during feeding in lactation) was given after the second year of life of the baby, and not before. That is, the maternal deprivation, the absence of regular contact with a nurturing mother during the first months of life, it was very harmful for going against what our genetics would have us programmed.

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 because of Second World War, Bowlby found significant evidence that young people who had experienced maternal deprivation from living in orphanages tended to introduce intellectual retardation and problems successfully managing 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 had a markedly passive attitude and flew into a rage much more easily than the rest of the youth.

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 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 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 this, he conducted an experiment with rhesus monkeys that under current ethical standards it would be unfeasible due to the cruelty that it involved.

What Harlow did was basically separating some baby macaques from their mothers and observing how their maternal deprivation was expressed. But he did not limit himself to passively observing, but he introduced into this research an element 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 of them was a wire frame with a full bottle built in, and the other was a figure similar to an adult macaque, lined 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 young are related to their mothers basically by the food they provide them, which objectively is 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. Their attachment to this object was much more noticeable than that they professed to the structure with the bottle, which was in favor of the idea that it is the intimate bond between mothers and young that is really important, and not the 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 ones macaques decided to undertake certain tasks on their own initiative and hugged it even more tightly when They had 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 would recover, though they remained on the defensive in case this artificial mother was lost from sight 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. He did it by confining the young of this animal species in closed spaces, keeping them isolated from any type of social or sensory stimulus.

In these isolation cages there was only one trough, one trough, which was a total deconstruction of the concept of "mother" according to behaviorists and Freudians. In addition, in this space a mirror had been incorporated thanks to which you could see what the macaque was doing but the macaque could not see the observers of it. 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 obvious alterations in their behavior after having spent 30 days in the cage, but those who stayed a full year were left in a state of total passivity (related to catatonia) and indifference towards others about which they did not recovered. 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 even worse

When Harry Harlow decided to study the maternal behavior of the macaques he had been subjected to isolation, he encountered the problem that these female monkeys were not pregnant For 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 their young for most of the time, but occasionally mutilating 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 the investigations of John Bowlby and the experiments of Harry Harlow are highly regarded. currently counts, despite the fact that the latter are also a case of clear torture towards animals, Y 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 biological needs and that are linked to affective behavior during the first stages of life usually leave a very serious and difficult to erase mark on the adult life.