“Trick question, since dolphins obviously don’t have hands—but studying whether they have “handedness” led to identifying a quirk of human perception.”
the following written content by Kelly Jaakkola
Humans do not act symmetrically. Most of us prefer, and are better at, using one hand rather than the other; balancing on one leg rather than the other; and for those of us who spin (gymnasts, dancers or divers, for example), spinning in one direction rather than the other.
Brains also do not function symmetrically. A version of this idea has long lived in pop psychology, where people are sometimes characterized as being either left-brained (analytical) or right-brained (creative). And although the pop-psych version of this may rest on questionable data, the underlying idea of asymmetrical brain function (what scientists call lateralization) is well-established. For example, in humans, language is typically processed in the left hemisphere, while spatial information is processed in the right.
Because each side of the brain controls a different side of the body, studying asymmetrical behaviors can provide us with information about asymmetrical brain function. And if we study this in animals, it may give us insights into brain evolution.
HANDEDNESS WITHOUT HANDS
The type of lateralization most familiar to people is undoubtedly handedness. This has been studied in animals by looking at things like which hand monkeys use to grab something, which paw dogs use to knock food out of a container, and so on. But what do you do when the animal you’re studying doesn’t have hands (or paws)? How do you study lateralization in an animal like a dolphin?
It turns out that behavioral asymmetries come in various types, not just limb biases like handedness and footedness, but also sensory asymmetries, in which we do better on different types of tasks depending on which eye (or visual field) we use; and turning biases, where we prefer turning in one direction rather than the other. Read more from Scientific American.
