13.12.2017 change 13.12.2017

Love is linked to the number of children! A study of Polish researchers

Photo: Fotolia Photo: Fotolia

In traditional cultures, do couples that really love each other have more children? Polish researchers investigated that on the example of a Tanzanian people. It turned out that involvement in a relationship with a partner has a beneficial effect on reproductive success.

This is the first study that shows a direct link between love and reproductive success. The study - led by Prof. Piotr Sorokowski from the University of Wroclaw - appeared in the journal Frontiers in Psychology.

"We had a hypothesis that couples that love each other more would have more children" - said Prof. Sorokowski. He explained that such research makes sense only in traditional cultures that do not use birth control.

THE HADZA HAVE THEIR OWN WAYS

Researchers analysed this issue in the Hadza population that inhabits a part of Tanzania. "It\'s one of the last groups of hunters and gatherers in the world. Women gather plants and men hunt" - said the psychologist. He added that studying such groups can shed light on how human communities functioned in the past.

The psychologist said that the Hadza live in huts similar to tents, and move from place to place. They hunt with bows and arrows. "During their wanderings, the Hadza pass by villages, they see cars. If they wanted to, they could go to a store and buy a rifle, but they do not want to join the stream of modern life" - said Prof. Sorokowski. He added that the Hadza community now has about 1000-1500 people.

LOVE FORMULA: PASSION + INTIMACY + INVOLVEMENT

Researchers decided to investigate how much couples in the Hadza community love each other and how many children they have. But how to measure love? "The theory that is most popular in psychology assumes that love consists of three factors" - the researcher told PAP. These are passion, and therefore sexual engagement, intimacy, or closeness and warmth in the relationship, and commitment to the relationship. The latter means that the partners think that their relationship can survive for a long time.

Members of the community were asked if they agree with the sentences about the partners. The examples of the sentences were: "I know I can trust X", "I like physical contact with X" or "I can not imagine my life without X".

WHAT HAVE THE RESEARCHERS FOUND?

"The study showed that involvement in the relationship was a very good predictor of the number of children. So the people who thought that they were in a relationship that would last a long time, they had more children" - said Prof. Sorokowski.

Passion had a similar relationship with reproduction, but only in women. "If a woman lusted for her partner, it had a positive effect on the number of her children. In men, not necessarily so. This speaks well about the status of women in this community - these results would indicate that women decide whether a couple has an intercourse and when" - commented Pprof. Sorokowski.

Intimacy had the opposite effect. "The more intimacy, the less children. We do not know exactly why yet" - concluded the scientist from the University of Wrocław.

EVOLUTION OF LOVE

Researchers have long wondered if love - so common throughout the world - is an adaptive trait that is rewarded in human evolution. An adaptive trait should either facilitate the survival of the individual or his children, or increase the chances of reproductive success.

If it can be proven that couples in love have more descendants, then it will be confirmed that love is an adaptive trait. "To consider this hypothesis true, it would be necessary to have data from many communities, and we have only studied one. In addition, our results are not entirely clear" - said Prof. Sorokowski. And he added: "But we think that our results are a good clue to show why love could be rewarded in human evolution".

ARRANGED MARRIAGES ARE NOT LESS INVOLVED?

The study published in "Frontiers in Psychology" is the first such study of love and reproduction in humans. Previous experiments in this respect were carried out only on animals. It was shown that those individuals that paired themselves had more offspring than those that were paired by researchers. "However, it is impossible to extrapolate such results to people" - commented Prof. Sorokowski.

Prof. Sorokowski\'s team of earlier analysed (publication in "Scientific Reports"), in which traditional societies more children are born: those with arranged couples (for example, spouses selected by parents), or those where couples decide for themselves. It turned out that the method of partner selection did not affect the number of children. "However, this does not mean that love between partners is not linked with reproductive success. After all, it is not said that there is a lower level of love in arranged relationships" - noted Prof. Sorokowski and added that perhaps love also appears in such arranged relationships, only its dynamics is different...

The researchers decided to investigate this problem from a different angle. The result is the latest study published in "Frontiers in Psychology", in which subjects were asked more directly about their feelings towards their partners and the answers compared with the number of children.

Author: Ludwika Tomala (PAP)

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