Love is present, in one form or another, in almost every aspect of life. Films, series and books, among others, are full of it in all its forms. They show couples who fall desperately in love, inseparable friends and families who make him the protagonist of their story. However, interest in this feeling is not limited to fiction. Science has also been studying it for a long time and trying to unravel its secrets. Research from Aalto University (Finland) used magnetic resonance imaging to see how the brain behaves when faced with different types of love.
The work, published this month in the magazine Cerebral cortexindicates that brain activity is influenced by the proximity of the love object and whether it is a human, another species or nature. These scientists established six types of love: romantic, paternal, for friends, for strangers, for animals and for nature. We measured brain activity while these people listened to and reflected on approximately 15-second narratives describing scenarios with each of the affect types described.
The results showed that romantic love and that felt towards children are the two that activate more areas of the brain and do so more intensely. They are the ones that stimulate the reward system the most. Juan Lerma, CSIC researcher at the Institute of Neurosciences of Alicante (Csic-UMH), affirms that behind this result there is “a very important biological or evolutionary value”.
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El primero sirve para asegurar la reproducción, que las personas busquen una pareja y tengan descendencia para preservar la especie humana. El segundo asegura que los padres protejan a su progenie para poder continuar el proceso biológico. Si no activara esos centros de recompensa, como el cuerpo estriado y el tálamo, la espacie no perduraría, expone Lerma. “No tendríamos ninguna motivación para hacer el amor, tener hijos, o para cuidarlos”.
No es la primera vez que se observa algo así. Hay numerosas investigaciones que ya han demostrado que ambos sentimientos afectan a zonas del cerebro asociadas con la recompensa, el apego, la motivación y el aprendizaje de refuerzo, afirman los investigadores. De hecho, el ser humano no es el único mamífero al que le ocurre. Este tipo de efecto también se ha visto en los topillos de la pradera, que son monógamos y permanecen toda su vida con la misma pareja.
En las relaciones interpersonales, se ha observado que el que tiene menos fuerza es el amor por los extraños. Es el que muestra menos actividad en cuerpo estriado y el tálamo. La investigación destaca que este sentimiento ha implicado siempre un comportamiento altruista que se ve correspondido por una expresión de gratitud. Por lo tanto, ese afecto no es de hecho amor de seguimiento, sino más bien compasión o altruismo, argumentan los autores. “Se evalúa [la experiencia] subjectively as less salient, less pleasant, less exciting and less affectionate,” they point out.
Love for animals and nature
Despite what one might believe, due to their presence in human life today, love for animals is also one of the things that stands out the least. Imaging results show less subcortical activation. The authors point out that less than half of the test subjects reported having pets, which could be a determining factor. In fact, they found that those who had furry companions at home had neural performance closer to interpersonal love than those who do not.
The CSIC-UMH neuroscientist indicates that love of animals lies in living with them. Lerma says that, according to several studies, the display of compassion or feelings towards them comes from the similarities they may have with humans. Give the example of a dog with big eyes that may give off a sad look. “It’s moving because these are human traits more than those of an animal”. He also points out that this research shows that you cannot love a pet in the same way as a person “because of the big difference in the activation of brain areas.”
The weakest of all was the attachment to nature. In this case, scientists found that reward areas and visual areas of the brain were activated, but social areas were not stimulated.
Strengths and limitations
Lerma points out that this is not the first study on the effect of love on the brain, but it was a pioneer in defining six types and assess neurological behavior in each case. “This allows us to establish how the brain determines behaviors that have adaptive value from a biological perspective.”
The work is also the one you used the largest cohort to datebut the neuroscientist believes that this is not enough and should be increased in future projects. The tests were carried out on 55 Finns and Lerma explains that to have a more realistic general picture, it would be advisable to do it with people from different countries and cultures. This alludes to the fact that this feeling has many conditions such as cultural, educational or family conditions, which make it experienced differently.
Despite the limitations, the CSIC neuroscientist appreciates the new knowledge provided by the study. He also assures that, even if these observations may seem banal, can be used to advance research. “Any information about the brain that improves what we know about it helps us better understand mental illness.”
