In contrast, whether older siblings feel favoured or not apparently makes no difference to their relationship with their parents; social comparison (one sibling comparing himself or herself to the other) plays into this.

The School of Family Life’s assistant professor Alex Jensen comments on the BYU website: “It’s not that firstborns don’t ever think about their siblings and themselves in reference to them. It’s just not as active of a part of their daily life.

“My guess is it’s probably rarer that parents will say to an older sibling, ‘Why can’t you be more like your younger sibling?’ It’s more likely to happen the other way around”.

The study, published in Journal of Adolescence, looked at more than 300 families (each with two teenage offspring), asking the children about their relationship with their parents and vice versa, and considered the amount of warmth and conflict between each party.

Interestingly, Jensen disputes the idea that parents should treat all children equally: “When parents are more loving and they’re more supportive and consistent with all of the kids, the favoritism tends to not matter as much.

“Some parents feel like ‘I need to treat them the same.’ What I would say is ‘No you need to treat them fairly, but not equally.’ If you focus on it being OK to treat them differently because they’re different people and have different needs, that’s OK.”

This report follows similar research earlier this year which suggests that youngest siblings believe themselves to be the funniest, with older siblings deeming themselves more organised and in control of their lives.

Image: Bruno Nascimento

This is why the youngest in the family thinks they’re the favourite