Maternal instinct can also be learned

Ducklings that have just hatched follow the first thing they see moving. Usually it is their mother, which works very well: the young gain protection, care, and food from someone who is like them. However, it does not have to be the mother. Austrian zoologist Konrad Lorenz discovered that he himself could become the unconditional reference point for goslings that saw him first after hatching, a phenomenon he described as imprinting. Photos of Lorenz in the water surrounded by his goslings became a staple in biology and behavior books—not only because Lorenz won a Nobel Prize in 1973, but also because he considered imprinting an example of a type of behavior that fascinates the public: instinct.

Instinct, in colloquial language, describes everything we know how to do without having to learn it. It sounds almost esoteric, but for neuroscience, the explanation is simple: instincts are behaviors organized by neural circuits that are either born functional or are there from the beginning, silent but ready to spring into action when they receive a signal. Mammalian babies suck whatever enters their mouths; fish babies swim alongside their brothers and sisters that hatch at the same time, forming schools from the beginning; baby geese follow the first thing that moves.

The opposite of imprinting is maternal behavior of protection and attachment to offspring, also considered instinctive because it occurs naturally, even in isolation. Laboratory mice exhibit maternal instinct as much as we humans do—which makes it possible to study the origins of such instinct, which neuroscience now knows to reside in circuits between the hypothalamus and the midbrain, which direct behavior long before the cerebral cortex has a chance to intervene.

The powerful signal that triggers these circuits and sets off maternal behavior is the same one that, in offspring, generates attachment to the mother: the flooding of the brain and body with oxytocin, a hormone and neuromodulator released in massive doses during childbirth and breastfeeding.

It turns out that just watching mothers caring for their young also activates neurons in the hypothalamus that produce oxytocin, even in the brains of young virgin females with no experience with offspring, who then begin to act like mothers, helping with the young. This is shown in a study recently published in the journal Nature, which consisted of “simple” observation of the behavior of virgin female mice and their hypothalamic neurons—which requires mini-microscopes implanted in the brain, something only available to scientists in developed countries, such as the US, where the study's authors are based.

In other words, even maternal instinct can be learned through observation. Who knows, maybe one day this will also work with the appreciation of science...

Extracted from Suzana Herculano-Houzel (2025) Neuroscience of Everyday Life, originally published in Folha de São Paulo in September 2021.