Auditory distraction and serial recall

Elliott (2002) predicted that since rehearsal undergoes change as children develop (Flavell et al., 1966; Tam et al., 2010), it was reasonable to expect that younger children would show less interference-by-process relative to adults, if distraction was underpinned by rehearsal. Thus, children who rehearse TBR items less efficiently or not at all (rehearsal emerges around age 7; Flavell et al., 1966) would have poorer linkages

33

between the items compared to older children and adults, thereby resulting in smaller disruptive effects that stem from an interference of rehearsal in the youngest group. However, if distraction was based on attentional control then there should be larger effects of distraction for younger children. Developmental improvements in memory and efficiency of attention would mean that children show much more disruption by irrelevant sounds because their attentional control is inferior relative to adults. The results obtained by Elliott (2002) were in favour of the latter prediction based on attentional control and children were more distracted by speech than sounds while adults were not. Less efficient attentional control may have compromised children’s ability to tag and rehearse relevant visual items and to ignore irrelevant auditory

elements thereby leading to poor recall with more errors than older participants (Elliott, 2002; Klatte et al., 2010).

The link between the ISE and short-term memory capacity (as assessed by a digit span test) and working memory capacity (as evaluated by operation span) among children was considered in a study by Elliott and Cowan (2005). The findings from this study were, on the whole, concordant with evidence that memory span is not an

indicator of individual sensitivity to the ISE (Beaman, 2004; Ellermeier & Zimmer, 1997; Neath, Farley, & Surprenant, 2003; Sörqvist, Marsh, & Nöstl, 2013; cf. Elliott, Barrilleaux, & Cowan, 2006). However, there were some positive correlations between memory span, operation span and the magnitude of the ISE for adults and children. This pattern of results conflicts with the expectation of smaller disruptive effects for more capable individuals (i.e. those with a higher span) as suggested by Elliott (2002),

Sörqvist, (2010a), and Sörqvist et al. (2013). In a Bayesian meta-analysis, Sörqvist et al. (2013) showed that the magnitude of the ISE and / or CS effect is unrelated to WMC, however, the deviation effect is modulated by WMC such that an increase in WMC

34

leads to a decrease in the deviation effect (similar results observed by Hughes et al., 2013 & Sörqvist, 2010a; for a review, see Sörqvist & Rönnberg, 2014).

While Elliott and Cowan (2005) propose that the correlations could be a “statistical artefact” as span may be related to recall scores in the silent condition that were used to calculate the magnitude of the ISE, they are more likely to reflect a deleterious effect of irrelevant sounds on mnemonic processing such as rehearsal that was used in the focal task (e.g., Beaman & Jones, 1997; Jones, 1993). Higher span individuals may rely on rehearsal more than less capable individuals and if this processing was interrupted by irrelevant sounds then those who engaged in a greater level of rehearsal would experience greater disruption as manifested by more errors in recall (e.g. Beaman & Jones, 1997, 1998; Jones & Macken, 1993). The absence of a negative correlation between digit span and the magnitude of the ISE is surprising as one would expect the factors responsible for improvements in span to also account for the developmental decrease in sensitivity to disruption by irrelevant sounds. These factors could include the developmental improvements in attentional control (e.g., Lane & Pearson, 1982; Zukier & Hagen, 1978) and covert rehearsal abilities (e.g., Flavell et al., 1966). However, given the evidence from this study, it appears that there may be different influences on the development in span and the degree of the ISE. In fact, as Macken et al. (2009) have shown, serial recall performance does not correlate with distractibility, therefore, a measure of WMC (i.e. memory span) that relies on such a task will not correlate with the ISE and / or CS effect either. Furthermore, as Sörqvist (2010a) and Sörqvist et al. (2013) suggest, a relation between distraction and WMC may be evident only when distraction is the result of attentional capture and not when it is underpinned by an interference of rehearsal processes. High and low WMC

individuals will be equally susceptible to the ISE and / or CS effect because these effects depend on the conflict between rehearsal and obligatory streaming of auditory

35

information rather than the availability of executive resources (as indexed by WMC). When this is extended to developmental differences, it could suggest that children and adults should show equivalent irrelevant sound / CS effects but should vary in the deviation effect on account of different attentional capacities (high and low WMC individuals vary in the magnitude of the deviation effect; Sörqvist, 2010a; Sörqvist et al., 2013; see also Klatte et al., 2010).

In contrast with the foregoing studies, a study by Klatte et al., (2010) showed that the ISE was present for both children and adults but there was not the same striking difference between adults and children in the magnitude of disruption as noted by Elliott (2002). Klatte et al. (2010) required participants to recall the order in which a list of pictorially represented common nouns were presented. The nouns were phonologically dissimilar and of long (e.g., “Schmetterling”; the German word for butterfly) or short spoken duration (e.g., “Hund”; the German word for dog). Serial recall was completed in quiet, in the presence of irrelevant foreign speech (an article read from a Danish newspaper), and classroom noise which comprised typical classroom sounds but no speech (e.g., rattling of writing equipment, moving chairs, coughing). It is important to note here that the nature of the classroom noise was such that there was no predictable order among the sounds, therefore, the likelihood of order cues in the sequence was very low (Klatte et al., 2010). Results showed that recall performance of the youngest

children (median age of 7 years, 0 months) was poorer in the presence of classroom noise compared to quiet unlike the older children (median age of 8 years, 5 months) and adult participants (median age of 22 years) who did not show significant disruption by classroom noise. By contrast, children and adults exhibited disruption by irrelevant speech. The expected differences in attentional control between the age groups coupled with the notion that classroom noise would not generate order cues were cited as reasons for the age-related finding.

36

These results were taken to be an indication of two separate forms of distraction, in line with the duplex-mechanism account (Hughes et al., 2007), where irrelevant speech caused distraction by interfering with rehearsal processes, and, classroom noise captured attention. The magnitude of the former was similar for children and adults while the latter was more pronounced for the young children as compared with the older children and adults. The finding that younger children were distracted by classroom noise (in addition to speech) suggested that they may show greater susceptibility to distraction because of poorer attentional control — similar to the conclusions drawn in studies by Elliott (2002) and Elliott et al. (2016). However, this study has been criticised for using a methodology that places lower demands on rehearsal and attentional control than a standard serial recall task with verbal material as the TBR items (Elliott et al., 2016). If the demands on rehearsal and attention were so low as to automatize their task performance then the effects of distraction would be minimal (Neumann, 1987).

Although Klatte et al. (2010) hinted that their results may be in line with the duplex-mechanism account of distraction (Hughes et al., 2007), they did not interpret the results within this framework. Instead, they explained the disruption to recall by irrelevant speech with reference to the O-OER and phonological store models

(Baddeley, 1996; Jones & Macken, 1993) while the disruption by classroom noise for the youngest children was best accounted for as attention capture within the Feature model (Neath, 2000). In line with the phonological store perspective, the results showed that disruption among older children and adults was dependent on the distraction

consisting of speech. Incoming visual and auditory information enter the phonological store through rehearsal and automatic access, respectively (Baddeley, 1996). The process of rehearsal serves two purposes — to convert visual information from graphemes to phonemes (for entry into the phonological store) and to maintain the traces of visual information within the phonological store (Baddeley, 2002). A conflict

37

arises between the information that originates from the visual and auditory modalities because of their phonological similarity; and, since the irrelevant speech is processed automatically it masks the traces of TBR items leading to poorer recall (Salamé & Baddeley, 1982). However, this model is unable to account for the disruption by

classroom noise since it emphasizes the need for phonological similarity in determining disruption.

According to the O-OER model, the detriment to recall is attributed to interference between relevant and irrelevant order cues. Therefore, the model can account for disruption by speech and non-speech effects so long as there are order cues in the irrelevant material that could interfere with those from relevant items (Jones & Macken, 1993). Nevertheless, in the study by Klatte et al. (2010), classroom noise was assumed to be devoid of order cues and as such should not be expected to cause disruption to serial recall. Therefore, the disruption by classroom noise among the youngest children contradicts this assumption and does not align with the O-OER model. This leaves the Feature Model (Neath, 2000) to account for the effects of classroom noise among the youngest group of children. According to this model, non- speech sounds do not cause disruption through the feature adoption process but rather through the capture of attention. To incorporate their results within the feature model, Klatte et al. (2010) suggested that because classroom noise contained many different acoustic events in an unpredictable order it would be difficult to ignore. This would be especially true for the youngest children because of their poor attentional control. From the perspective of the feature model, this would translate to a smaller attentional

parameter to reflect children’s poor attentional control and the nature of classroom noise (Neath & Suprenant, 2001). Taken together, this would result in disruption to recall performance by classroom noise only for the youngest children. However, given the difficulties of the feature model to adequately explain irrelevant speech and non-speech

38

effects (discussed in Section 1.2.1), the interpretation of results using the model should be treated with caution.

The findings from Klatte et al (2010) suggested there may be scope for the application of the duplex-mechanism account to distraction effects among children. This was explored to a larger extent in a study by Elliott et al. (2016) and shed light on the contribution of rehearsal and attentional control in auditory distraction effects among children and adults. Among adults, greater disruption to serial recall was observed when irrelevant sounds coincided with points wherein the demands on serial rehearsal were particularly great (Macken et al., 1999). Armed with the knowledge that children’s rehearsal is still emerging, Elliott et al. (2016) tested the hypothesis that children will show greater sensitivity to distraction than adults as the rehearsal load increased. Children and adults completed a serial recall task in the presence of irrelevant speech and in quiet. Serial recall for children and adults was impaired by speech particularly in the latter half of presentation and all through the retention interval when the rehearsal load was at its highest. In addition, the results showed that children were more

susceptible to disruption than adults which concurs with previous work showing that the magnitude of the ISE was greater for children than college students (Elliott & Briganti, 2012) and those studies showing an increased ISE for younger children compared to older children (e.g., Elliott, 2002; Elliott et al., 2007). Although the evidence from this study suggested that children’s inefficient rehearsal may make them more susceptible to distraction of the interference-by-process type, Elliott et al. (2016) offered an alternative explanation which attributes children’s particular susceptibility to distraction to

attentional control factors. They proposed that since children have smaller working memory capacities (Cowan et al., 2005), and less inhibitory control over irrelevant stimuli (Hwang et al., 2010), the underdeveloped rehearsal could actually impose an

39

attentional load that makes them particularly unable to ignore irrelevant sound and rehearse TBR items.

For the purposes of isolating rehearsal or attentional control as the basis of children’s greater distractibility, Elliott et al. (2016, Experiment 2) contrasted

distraction effects in tasks with and without a serial rehearsal component. Differences, if any, in the effects across these tasks, would demonstrate whether children’s greater distractibility was simply a result of poor attentional control or a greater susceptibility to interference-by-process. As mentioned in the foregoing, among adults, studies have consistently shown that the CS effect is absent when serial rehearsal –the process

essential for interference-by-process to occur —is suppressed (e.g., Hanley, 1997; Jones et al., 2004) or absent altogether (e.g., Beaman & Jones, 1997; Perham et al., 2007). However, the study by Elliott et al. (2016) was the first to test if this pattern also holds for children. If children’s greater susceptibility is underpinned by attentional control and not rehearsal, then they should show disruption regardless of the processes needed for the focal task and regardless of the type of irrelevant sound (steady or changing). Elliott et al. (2016) demonstrated that children and adults were susceptible to interference-by- process in the task involving serial rehearsal and the magnitude of this effect was similar across ages. The finding that children’s short-term memory was affected appreciably in both tasks by sound in general (steady or changing) supports the notion that children’s poor attentional control underpins their greater sensitivity to distraction.

1.3.2 Effects of irrelevant speech outside the serial recall paradigm.