It’s not up to you whether the glass is either half empty or half full. Science says so.

We all know the old adage that the optimist sees a half-glass of water as half full while the pessimist sees it as half empty. A variety of studies have revealed the positives and negatives of both outlooks. For example, optimists have healthier hearts, while pessimists might be better able to achieve their goals. Something that might be news, though, is that we don’t necessarily choose to see the world the way we do.

According to AsapSCIENCE, research has shown that those who have two long alleles on specific genes that control serotonin might be more predisposed to focus on positive images. On the other hand, those with short alleles on the same gene might focus more on negative images.

Additionally, variations in the genes’ oxytocin receptor can also influence a person’s outlook: those with two copies of guanine are typically more optimistic and have higher self-esteem. On the flip side, those with two copies of adenine are generally less positive.

While this is definitely interesting, the fact that people may have a genetic predisposition to be more negative isn’t exactly news. The link between the 5-HTT serotonin transporter gene and depression has been widely acknowledged since 2003 and subsequent studies and articles also linked 5-HTT to binge drinking, panic disorders, and other issues.

However, a link between the gene and depression doesn’t reveal causation. In fact, other studies have found that environment and life experience might factor in heavily in whether you’re an optimist or a pessimist.

AsapSCIENCE also reminds us that statistically, most of us are hard-wired for optimism: the brain is actually more active when you’re thinking positively. Whether this is some sort of subconscious choice by the brain to filter out the negative, or whether it is in fact rooted in genetics, is unclear.

There’s definitely enough evidence to suggest that being optimistic isn’t totally within your control; but you do get to choose what to do with this information — we suggest filling a (not proverbial) glass with your favorite beverage and enjoying your weekend!

(Image via iStock)