attention span

/AH0 T EH1 N SH AH0 N S P AE1 N/
noun
  1. 1

    The length of time, or span that one can pay attention, or concentrate on one topic without becoming distracted.

    โ€œHe has learning difficulties because of his short attention span.โ€

Source: https://en.wiktionary.org/wiki/attention%20span