The ease with which a person's concentration can be interfered with by external stimulation or by irrelevant thoughts(noun)
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Use "distractibility" in a sentence
"“It may be that distractibility is not, in fact, a bad thing,” said Shelley H. Carson, a psychology researcher at Harvard whose work was cited in the book."
"It is agitating in the way it embodies the distractibility of contemporary life, but it is also trenchant and thought-provoking—a slog to read, in other words, but a pleasure to ponder."
"Apart from low motivation, IQs are sometimes invalid estimates of a person's true functioning because behaviors such as distractibility, anxiety, or low frustration tolerance can interfere with test performance and lead to a low IQ or a low standard score on a test of working memory -- even when the person truly has exceptional ability."