Everybody, go ahead and cross your arms right now. Done? Alright. Now, try to cross them the other way. If you’re currently crossed with right forearm on top, try to switch position so that your left forearm is on top. Feels incredibly awkward and unnatural, doesn’t it?

It turns out most people have a natural bias for arm-crossing direction, with slightly more than half of most global populations preferring the left-forearm-on-top approach, although the two preferences are basically 50-50. Some people apparently cross their arms either way without even thinking about it, although this population is exceedingly small.

So why do we humans find one way so natural and the other way so incredibly weird-feeling? It may have something to do with your psychological composition, according to the (admittedly somewhat unreliable) Japanese Internet.

This graph breaks it down:


Here we see a cross-section of personality type and arm-crossing and finger-weaving preference. To figure out your finger-weaving preference, interlock your fingers like you’re Oliver Twist begging for more porridge and pay attention to which thumb is on top; You’ll obviously be either right-thumbed or left-thumbed.

Let’s take a look at a breakdown of what each category means:

If you both cross your arms and weave your hands right-over-left, you apparently are inclined to think critically before arriving at a first impression, and think critically when confronting problems or drawing deeper conclusions.

Those that cross their arms right-over-left, but weave hands left-over-right tend to go with their gut when it comes to first impressions, but give more logical thought to things when drawing deeper conclusions or confronting a problem that needs solved.

Left-over-right arm-crossing hand-weavers are supposedly the most brash of the bunch, leaving everything up to gut instinct.

Finally, if you tend to cross your arms left-over-right but weave your hands right-over-left, then your first impressions tend to be well-thought out, while you leave more complex issues to instinct.

For further proof, here’s a diagram about left-brain and right-brain or something:


Here’s the part where I’m supposed to tell you that I tried this myself and found that my arm-crossing and hand-weaving preferences and problem-solving style matched closely with the conclusions drawn by these diagrams, but that’s actually not what happened.

In fact, it appears arm-crossing and hand-weaving preferences are largely random, probably chosen by each individual as a child when first learning to perform these actions and reinforced over many years until going the opposite direction starts to feel very unnatural. Family studies have borne this out, with right-over-left-preferring parents giving birth to left-over-right-preferring kids about 50% of the time, and vice versa. Even more damning to the theory put forward by the above diagrams, twins have opposite arm and hand-folding preferences about as often as they have the same preferences, strongly indicating that genetics don’t influence an individual’s preference and, subsequently, that it’s probably not a strong indicator of psychological tendencies.

Apparently, some people also believe that this Geocities-era Internet spam .gif is an accurate predictor of left or right-brained-ness:

Never mind that the dancer frequently switches spinning direction the more you look at it.


But hey, it’s fun to think about it, right? And it’s at least (probably, ever so slightly) more scientifically sound than trying to read the future in animal bones.

Source and photos: Kininaru Sokuhou