The aim of this analysis was to exploit the differences between the probed recall and missing-item task and show how the two forms of distraction as set out by the duplex-mechanism account can be distinguished from one another. The presentation of TBR items and the requirement of a single response are identical for the two tasks. There is, however, a variation in the strategy used for the tasks: for the probed recall
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task, participants must identify which item followed another in the list and so must remember the order of the items in the list; but, for the missing-item task they must choose the one item that was missing during presentation and the retention of order is not essential. While the probed recall task is thought to involve the use of serial rehearsal, the missing-item task does not require such processing, and, as Morrison, Rosenbaum, Fair, and Chein (2016) have found, individuals engage in a variety of strategies (e.g., checklists, grouping) to ascertain the missing item. This is a key
difference which generally results in the presence of the CS effect only in the task with serial rehearsal (i.e. probed recall; Beaman & Jones, 1997). However, the presence of the deviation effect regardless of task type will show how attention is vulnerable to capture regardless of the processes used in the focal task (e.g., Hughes et al., 2007 Vachon et al., 2016). The addition of age group comparisons to the analysis will provide information on how these underlying processes determine disruption by irrelevant auditory material in children versus adults.
A 2 (State: Changing or Steady) × 2 (Deviation: Present or Absent) × 2 (Task: Probed Recall and Missing-item) × 4 (Age Group: 5-6, 7-9, 10-11-year-old children, and 18-22-year-old adults) mixed ANOVA was conducted. State, Deviation and Task were the within-subjects factors. The main effects of the within- and between-group factors were all significant (see Table 3.2). The main effect of State showed that overall performance in CS speech was lower than that in SS speech. Recall was lower in the presence of deviants compared to when they were absent as indicated by a significant effect of Deviation. The significant effect of Task showed that probed recall
performance was lower than that of the missing-item. Finally, the significant effect of Age showed that adults’ performance was significantly better than 5-6 and 7-9 year old children only. However, the focus of this section is on the interactions of State and Deviation with Age and/or Task. These interactions would show whether the CS and
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deviation effect manifested differently in the probed recall and missing-item task as a direct consequence of whether serial rehearsal was used in the task or not. The addition of Age Group as a factor was to ascertain whether the CS and deviation effect vary in their presentation in the two tasks as a function of age-related differences in the use of rehearsal and attentional control.
As there were several non-significant interactions between factors, these are presented in Table 3.3. There were, however, two significant interactions: State × Deviation, F(1, 193) = 4.10, MSE = .10, p = .044, ηp2= .02 (the simple main effects are not reported here so as to remain focused on those interactions with Task and Age Group); and, Task × Age Group, F(3, 193) = 4.32, MSE = .36, p = .006, η2p= .06, which showed that performance levels in the tasks varied with age. Simple main effects
analyses showed that performance in the probed recall task (M = .35, SD = .16) was significantly lower than the missing-item task (M = .50, SD = .18) for children aged five and six years old, F(1, 46) = 21.23, MSE = .53, p < .001 ηp2= .32. The effect of Task was not significant for 7-9-year-old children [F(1, 49) = .50, MSE = .01, p = .481, ηp2= .01], 10-11-year-old children [F(1, 49) = .60, MSE = .01, p = .444, η2p= .01], and adults [F(1, 49) = 3.35, MSE = .08, p = .07, ηp2= .06].
127 Table 3.2
Main effects of State, Deviation, Task, and Age Group on recall performance
Main Effect df MSE F p
State 1, 3 .20 6.01 .015 .03
Deviation 1, 3 .45 17.12 <.001 .08
Task 1, 3 1.48 17.73 <.001 .08
Age Group 3, 193 .15 4.56 .004 .07
Table 3.3
Non-significant interactions between factors State, Deviation, Task, & Age Group
Factors df MSE F p
State, Deviation, Task, Age Group 3, 193 .03 1.45 .231 .02
State, Deviation, Task 1, 193 .04 1.65 .201 .01
Deviation, Task, Age Group 3, 193 .07 2.49 .061 .04
State, Task, Age Group 3, 193 .06 1.90 .132 .03
State, Deviation, Age Group 3, 193 .01 .53 .659 .01
Deviation, Age Group 3, 193 .01 .30 .826 .01
State, Age Group 3, 193 .01 .28 .843 .004
Deviation, Task 1, 193 < .001 .01 .921 .01 State, Task 1, 193 .02 .55 .461 .003 2 P
η
2 Pη
128 3.4 Discussion
The aim of this discussion is to provide a cross-sectional view of the effects of irrelevant speech on recall performance in tasks with and without a serial rehearsal component. Children ranging in age from 5 to 11 years old completed a series of tasks in the presence of irrelevant speech and in quiet. The children’s performance was contrasted with that of adults aged 18 to 22 years old. Participants in this study
completed three recall tasks in quiet and in the presence of irrelevant speech. Two of the tasks—serial recall and probed recall—are thought to require the use of serial rehearsal to assist task performance while the remaining task, the missing-item task, does not seem to utilize the serial rehearsal. The irrelevant speech comprised steady-state, changing-state, and deviant sequences. Mean recall scores in quiet was used as baseline performance.
The irrelevant speech effect, which is the finding that recall performance is poorer in the presence of irrelevant speech compared to quiet, was found in all three tasks. There were, however, mixed findings regarding which age groups were affected by which type of irrelevant speech sequence. Examination of the ISE on serial recall showed that while adults’ recall was poorer in all irrelevant speech conditions compared to quiet, the recall performance of 10-11-year-old children was poorer only in CS and CS + d speech, and the recall performance of the 7-9-year-old children was lower only in CS + d speech when compared to quiet. The scores of the 5-6 year old group in the presence of irrelevant speech were not significantly lower compared to quiet. For the probed recall task, adults had lower recall scores in all irrelevant speech conditions compared to quiet while the 5-6-year-old children experienced a detriment to recall in all irrelevant speech conditions except SS speech compared to quiet. For the oldest children, the presence of the ISE in the probed recall task was manifest as poorer recall only in the presence of SS + d speech compared to quiet. The ISE on the missing-item
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task was present only for 7-9-year-old children where performance in deviant conditions was lower than in Quiet. Performance in the missing-item task in CS and CS + d was lower than that in Quiet for the adults.
The CS effect, which has been consistently observed in tasks that require the retention of order (e.g. serial and probed recall; Elliott et al., 2016; Hughes & Jones, 2005), is the finding that serial recall accuracy is diminished to a larger degree by speech and sounds that vary acoustically than by sounds that are constant or steady in nature (Jones et al., 1993). Therefore, it is the difference in recall scores between CS and SS speech. The CS effect is thought to be dictated by the acoustic nature of the irrelevant sounds and the involvement of serial rehearsal in task performance because it is the conflict between order cues from relevant and irrelevant sources that results in poor recall scores (Jones & Macken, 1993; Hughes, 2014; Hughes & Jones, 2005; Tremblay & Jones, 1998). In the present study, as predicted, the CS effect was present only in the serial and probed recall tasks and not in the missing-item task. None of the age groups had a CS effect in the missing-item task while the effect was present for serial and probed recall tasks only for 10-11-year-old children. In addition, the CS effect was present for adults but only when their performance in deviant conditions (i.e. CS + d and SS + d) was included in the analysis. This is a novel finding and will be addressed shortly.
The deviation effect is best explained as attentional capture by an unexpected element within the auditory sequence that is different from the prevailing sequence of irrelevant sounds (Hughes et al., 2005; Jones et al., 2010; Näätänen, 1990) such as an unexpected male-spoken letter placed in a sequence of female-spoken letters as used in the present study. This deviation effect was noted across all three tasks and shows how this type of disruption manifests regardless of the processes needed for task completion
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(e.g., Hughes et al., 2005, 2007). Although the developmental differences analysis suggested that the deviation effect was present regardless of age, the individual age group analyses suggested otherwise. The youngest children and the adults did not demonstrate a deviation effect in any of the tasks. In contrast, the 7-9 year old group’s recall performance in serial recall and missing-item tasks exhibited the deviation effect while the 10-11-year-old children showed the effect only on the probed recall task.