The Puzzles of Handedness

Cari Neirenberg has an interesting article about left-handedness.

The truth is we know little about why people prefer to use one hand over another, and it’s unique to humans to have a large right-handed majority. In the animal world, there are roughly equal numbers who prefer their left paw to their right.

Most of the material in the article is taken from the book The Puzzle of Left-Handedness. 

As a left-hander, I’ve always felt that right handers over-estimate the uniqueness of being left-handed. However, there’s some interesting research that suggests your handedness affects how you learn and perceive your environment. 

For example, there’s a line of research that suggests our observational learning is increased when the person we’re observing has the same handedness as we do. This is intuitive to me, since there’s less processing for our brain to translate someone else’s movements into our own. 

(Random thought: I’m thinking of taking martial arts classes at the beginning of the year….maybe I should take the handedness of my instructor into consideration?)

Our handedness also affects our emotional affiliations. Left-handed people are more likely to make positive attributions to items simply because they appear on their left side. Ditto for right-handers. In controlled experiments this has consistently been the case, but “natural experiments” that map out spontaneous movements show the same result.

A cute example is a paper that studied the hand gestures of presidents during the debates. Dubya and John Kerry are both right-handed, and Obama and McCain are both left-handed. The researchers graphed their gestures against “good concepts” and “bad concepts” to see if there was a correlation. Here’s the result:

Speakers associate positive messages more strongly with dominant hand gestures and negative messages with non-dominant hand gestures, revealing a hidden link between action and emotion. This pattern cannot be explained by conventions in language or culture, which associate ‘good’ with ‘right’ but not with ‘left’; rather, results support and extend the body-specificity hypothesis.

The full text of the paper is here. 

I don’t know of any research that studies this particularly, but I’d be interested to see if non-dominant bodily gestures correlate with lying and truth-telling.