Developmental differences in the vulnerability to auditory distraction: children vs. adults

The thesis addressed whether there are developmental differences in the effects of auditory distraction on short-term memory among children and adults. The theoretical accounts and research addressed in the thesis highlight how rehearsal and attentional control play a role in the observed developmental differences. Rehearsal and attention do not work in isolation but rather interact with one another to enable successful execution of many different tasks (Elliott et al., 2016). One such instance of the interaction between rehearsal and attentional control is when short-term memory tasks are performed in the presence of auditory distraction (Hughes et al., 2007). Developmental research within the irrelevant sound paradigm has shown how rehearsal and attention can be affected by task-irrelevant sounds in different ways, how the efficiency of the two can determine distraction effects, and that the study of distraction is a window into the development of rehearsal and attentional control in children. Although there are different perspectives on the effects of auditory distraction, two accounts have dominated recent understanding. The duplex-mechanism account suggests there may be at least two functionally different types of distraction, one that is the result of interference with rehearsal and the other that is the result of attentional capture (Hughes et al., 2007). This account leads to predictions about the nature of the sounds and the characteristics of tasks that exhibit the most disruption (Hughes, 2014). The unitary account proposes that distraction is only the result of attentional capture and thus attributes less significance to the type of distracting material and task used (Elliott, 2002; Cowan, 1995). The weight of evidence so far is in favour of a duplex account of distraction (Jones, 1994; Jones & Macken, 1993; Jones, Hughes, Marsh, & Macken, 2008; cf. Bell et al., 2012; Korner et al., 2017). Rehearsal supports verbal serial short-term memory and is more vulnerable to auditory distraction wherein each token is different to the one preceding it (changing-state sounds such as A-B-A-B-A) than a steady-state sequence where the tokens are the same (e.g., A-A-A-A). This type of distraction is called the changing-state effect and manifests only when rehearsal is involved (Jones et al., 1992). Attention is needed for the maintenance of items in memory and can be captured by sounds that are unexpected (deviant sounds such as A-A-A-B-A-A-A; e.g., Hughes et al., 2013; Vachon et al., 2016). This is the deviation effect and it occurs regardless of processes involved in the task (Vachon et al., 2016; Hughes et al., 2007). The present empirical studies make use of changing-state and deviant sounds to investigate how distraction effects vary among children and adults. The experiments herein are the first to assess the deviation effect, ‘token set-size effect’ and ‘dose effect’ among children — token set-size and dose effects are findings that disruption to rehearsal increases when the number of irrelevant auditory tokens and rate of transition between tokens increase (Bridges & Jones, 1996; Tremblay & Jones, 1998). Results from each of the three empirical studies (and from a joint analysis of data from all three studies) suggest that overall, children and adults are especially vulnerable to distraction stemming from the interference of rehearsal as evidenced by the changing-state effect in serial and probed recall tasks but there was no difference in the magnitude of disruption between age groups. The results also suggest that the deviation effect may manifest more frequently for children than adults and this could be attributed to their poorer attentional control relative to adults. In addition, the combined analyses revealed a greater deviation effect for children compared to adults in serial recall. Taken together, the results suggest that developmental differences are more likely to emerge as a function of differences in attentional control rather than the efficiency of rehearsal. Implications of these results for theories of short-term memory, attention, and distraction are discussed. Practical applications of these findings for learning environments such as schools are also addressed.