twig

Impulse by Dr David Lewisを読み終えたので、次の本を借りるまで又Emotional First Aidを読みます。
In a study conducted in my own laboratory, autistic participants were shown a specially recorded drama. The short sequence depicted a man who is having an affair with his wife's best friend. Although non-autistic members of the audience twigged what was going on almost immediately, none of those with autism had the slightest idea.
"twig" の単語を覚えたのは、６０～７０年代に細い手足の若い女性歌手、Twiggyの歌が流行した時ですが、動詞の "twig" は5年前 (1/5/2012)に Kazuo Ishiguroの 'Never Let Me Go' を読んで知りました。
動詞としての "twig" は英国人は使いますが、米国では知らない人も多い様です。
"twig": Understand or realize something.: it was amazing that Graham hadn't twigged before (Oxford English Dictionary)
動詞としての "twig" の語源に触れている箇所をThe Word Detectiveから抜粋します。
The verb "twig" (unrelated to "twig" meaning "small branch") has been in colloquial use in Britain since the mid-18th century. "I twig" is a more elegant way of saying "I see" or "I get it." The somewhat conservative folks at the Oxford English Dictionary don't even want to hazard a guess as to the origin of "twig" in this sense, but the etymologist Eric Partridge traced it back to the Gaelic word "tuig," meaning "I understand."