Howard I. Kushner

“It turns out that bipedal species of kangaroos not only display a left-forelimb preference but also, lacking a corpus callosum—that bundle of neurons connecting the cerebral hemispheres—resemble some persons with autism, a disorder sometimes connected to both left-handedness and an underdeveloped corpus callosum. These findings about kangaroos have been used as evidence for both environmental claims and genetic claims about the etiology of left-handedness.”
― Howard I. Kushner, On the Other Hand: Left Hand, Right Brain, Mental Disorder, and History

“As is often true when the media translate scientific hypotheses, the complexities and caveats of researchers are frequently sacrificed to the demands of provocative headlines and accessible summaries. The studies themselves are not bad science. Indeed, like the study I discuss below, they are methodologically sophisticated and intriguing. But identifying the etiology of handedness always turns out to be much more complex than it appears, not least of all because there is, as the respected New Zealand psychologist Michael Corballis writes, no agreement about how to define left-handedness.”
― Howard I. Kushner, On the Other Hand: Left Hand, Right Brain, Mental Disorder, and History