In other species, greater height merely provides the ability to reach the highest branch or scare off potential predators. As for thinness, that means consuming less and residing at the lower end of the food pyramid.
But being tall and thin, particularly for humans? According to a recent study, they're likely to thrive in their environment, especially socioeconomically.
According to findings published in the BMJ, British researchers determined that a person's height and weight may play a direct role in how much money he/she makes. The study found that for every two and a half inches in added height, a man made an average of almost $2,000 more annually and a 12 percent better chance of working a top-tier job.
The study also found that for each additional 4.6 points on the Body Mass Index, women earned $4,200 less per year. So while a person's environment certainly plays a role, this contrast between genders points to a genetic relationship in regard to this phenomenon.
"[Y]our environment, your lifestyle, can't change your genes," said senior author Timothy Frayling, a University of Exeter professor of human genetics, speaking to the New York Times. "The data shows that there is a causal effect from being genetically a bit shorter or fatter that leads you to being worse off in life."
In their study, the British researchers assessed almost 120,000 men and women aged 37-73 years old, with almost all (99.5 percent) being aged between 40 and 69, and employed a genetic method called Mendelian randomization. In an observational study such as this, this technique tests for a causal connection between human traits. In this case, the researchers looked at five different qualities in each person:
- education degree level
- job class
- annual household income
- Townsend deprivation index, a widely-used score to measure social neglect
- the age at which the subject completed full-time education
The research found an association, that additional height and lower weight led to economic advantages. This was true, "especially women’s BMI for income and deprivation and men’s height for education, income, and job class," the authors concluded. "These findings have important social and health implications, supporting evidence that overweight people, especially women, are at a disadvantage and that taller people, especially men, are at an advantage."
"Clearly things like 'Are women who are a bit more overweight being discriminated against in the workplace?' needs more investigation," Frayling said in an article by The Memo.
While past observational studies have pointed to height and weight as influential factors, this is the first study to find a strong link between these factors and material success. But since it's observational, the results are less compelling as to establishing a causal relationship.
"Are we as employers sitting in an interview room and subconsciously choosing the thinner woman rather than the fatter woman?" said Frayling. "If that's the case it's clearly bad for the woman, but it's also bad for society."