Beaman CP, Hanczakowski M and Jones DM (2014) The effects of distraction on metacognition and metacognition on distraction: evidence from recognition memory. Front. Psychol. 5:439. doi: 10.3389/fpsyg.2014.00439
http://journal.frontiersin.org/Journal/10.3389/fpsyg.2014.00439/abstract (open source full text)
According to the authors (p. 11), “The results documented in our study with free-report tests also reveal that effects of distraction do not end with impairing memory processes. Auditory distraction has important consequences for how accurate people are in monitoring their memory processes, as revealed by impaired resolution of confidence judgments under distraction. Even more importantly, auditory distraction modifies metacognitive control and thus shapes performance when the “don’t know”option is available in a memory test. Participants seem to be aware that auditory distraction is harmful for memory as they become much less confident in their correct responses when distraction is present (see also Ellermeier and Zimmer, 1997; Beaman, 2005b).