Why do some people smile so easily and others find it so difficult? A new study carried out by a team of scientists from Northwestern University (USA) and the University of Geneva (Switzerland) has determined that emotional reactivity depends on our DNA. The work has been published in the American Psychological Association journal Emotion .
The researchers analyzed the short and long alleles of the gene 5-HTTLPR (involved in the regulation of serotonin and therefore in depression and anxiety) of a group of 336 volunteers. Taking into account that humans inherit one allele (each gene has two alleles) from the mother and another from the father, the scientists wanted to find out if the length of the alleles had a direct link to sensitivity to emotions, in this case, positive.
Thus, the participants were subjected to three different experiments : in the first, they watched cartoons to check their reactions; in the second, they watched a subtly funny movie; Finally, they asked the couples to discuss an area of disagreement in their marriage. All experiments were recorded from start to finish and their emotional expressions recorded. Saliva samples were also taken from all participants.
Using the Facial Action Coding System , the researchers focused on the genuine or real emotions detected by this system. Data from all three experiments revealed that people with the short allele of the 5-HTTLPR gene showed greater positive emotional expressions than those with the long allele of the gene .
“Our study provides a more complete picture of the emotional lives of people with the short allele. People with short alleles can flourish in a positive environment and suffer in a negative one, while people with long alleles are less sensitive to environmental conditions ”, explains Claudia M. Haase, co-author of the study.
