How childhood care affects the brain and future relationships

Scientists compared animals raised by both parents with those raised by their mother alone. It turned out that the young animals in the second group received less care, and as adults, the brain networks associated with social behaviour and attachment functioned differently in them.

The main conclusion is not that ‘one parent is worse than two’. The study was conducted on animals, not humans. However, it helps us understand why early care, physical contact and a stable environment may be important for brain development.

Details

Steppe voles are of interest to scientists because they are unusual among rodents: males and females can form stable pairs and care for their offspring together. They are therefore often used as a model for studying attachment, social bonds and pair bonding.

In the new study, one group of pups was raised by both the mother and father. In the other group, the male was removed from the cage before the offspring were born, and the mother cared for the pups alone.

On the sixth day after birth, the researchers recorded the parents’ behaviour: how often they licked their offspring, looked after them, stayed close by in the nest, and how much time they spent outside the nest. In this way, the researchers assessed not just the formal family structure, but the actual amount of care the young received.

Once the voles had grown up, the scientists tested their behaviour towards a potential mate. The animals were placed next to an unfamiliar vole of the opposite sex, and the researchers then observed whether the adult vole would prefer its familiar partner or choose the unfamiliar animal.

What the study revealed

Voles raised by their mother alone received less direct care at an early age: less licking, grooming and warmth in the nest. In adulthood, this was linked to differences in brain function.

No marked differences were found in the formation of attachment to a partner among females: both those raised with two parents and those raised with their mother alone showed a preference for a familiar partner.

The picture was different for males. Males raised with both parents formed an attachment to a female partner. Males raised without a male parent, however, did not show the same consistent preference after 48 hours spent together.

Put simply, care received at an early age had a stronger impact on the behaviour of adult males when it came to forming a pair.

What was happening in the brain

The scientists also studied the animals’ brains using functional MRI. This method reveals which areas of the brain are working in synchrony. In other words, the researchers were not looking at a single ‘love zone’ or ‘attachment centre’, but at the connections between different parts of the brain.

They identified several brain networks linked to early experiences. Some differed depending on whether the animal had been raised by both parents or by its mother alone. Others were linked to the amount of care the offspring received in the first few days of life. Yet another set of networks was linked to behaviour in adulthood — including the formation of pairs.

This is important because attachment is not a simple reaction, nor is it just a single ‘switch’ in the brain. It involves systems related to emotions, reward, the recognition of other animals, odours, stress and social behaviour.

Why this matters

The research suggests that early care may be linked to how the brain sets the stage for future social bonds. For social animals, contact with parents is not just about food and warmth. It is also a signal of safety, closeness and stability.

But the findings should be interpreted with caution. This study was conducted on steppe voles, not on children. In humans, things are much more complex: a child may be supported by their mother, father, grandparents, other relatives, foster parents, school, therapy and their social environment. It is not just the family structure that matters, but also the quality of care, safety, the absence of violence, stability and the emotional availability of adults.

Therefore, this research should not descend into moralising about ‘complete’ and ‘incomplete’ families. Its purpose is different: early care can indeed have biological consequences, and scientists are trying to understand the mechanisms through which this occurs.

Background

The link between early experiences and future social behaviour has long been of interest to psychologists and neurobiologists. It is almost impossible to study such issues experimentally in humans for ethical reasons: one cannot deliberately alter childcare conditions for the sake of research.

Scientists therefore use animals that form stable social bonds. Steppe voles are better suited to this than many other rodents because they form pairs and exhibit parental behaviour similar to the family system found in social mammals.

The next step is to understand exactly which brain circuits play a causal role. MRI scans themselves reveal connections between brain regions, but do not prove that a specific network directly causes a particular behaviour. Further experiments are needed for this.

Source

Study: M. Fernanda López-Gutiérrez et al., “Parental rearing shapes brain functional networks and socio-sexual behaviours in the prairie vole”, Open Biology, 2026.