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Year : 2012  |  Volume : 14  |  Issue : 56  |  Page : 1-5
The role of rehearsal in a novel call center-type task

1 Department of Applied Psychology, Cardiff Metropolitan University, Cardiff, United Kingdom
2 CAE Professional Services, Ottawa, ON, Canada

Click here for correspondence address and email
Date of Web Publication29-Feb-2012

Laboratory research has long demonstrated the disruptive effects of background sound to task performance yet the real-world implications of such effects are less well known. We report two experiments that demonstrate the importance of the role of rehearsal to a novel call center-type task. In Experiment 1, performance of a novel train timetable task-in which participants identified four train journeys following presentation of train journey information-was disrupted by realistic office noise. However, in Experiment 2, when the need for rehearsal was reduced by presenting the information and the timetable at the same time, no disruption occurred . Results are discussed in terms of interference-by-process and interference-by-content approaches to short-term memory.

Keywords: Irrelevant sound, noise, seriation

How to cite this article:
Perham N, Banbury S. The role of rehearsal in a novel call center-type task. Noise Health 2012;14:1-5

How to cite this URL:
Perham N, Banbury S. The role of rehearsal in a novel call center-type task. Noise Health [serial online] 2012 [cited 2023 Jun 7];14:1-5. Available from: https://www.noiseandhealth.org/text.asp?2012/14/56/1/93308

  Introduction Top

Extraneous noise in the office environment has been argued to adversely affect both workers' performance and health. [1],[2] This may have serious implications in the light of the recent rise in call centers in which workers are exposed to frequent irrelevant sound. [3] Although there is a strong history of research investigating the effects of irrelevant sound on performance on simple laboratory-based task, [4] for a review, it is only recently that this research has been applied to the office environment. [1],[5],[6],[7],[8],[9] However, it may be argued that these tasks- serial recall, prose recall and mental arithmetic - may not be as representative of a call center task. Thus, the present paper continues to investigate the effect of auditory distraction on task performance using a more realistic call center task set in the context of a train timetable inquiry service where the employee is tasked with identifying the most appropriate choice of train journeys from a timetable when provided with a list of criteria given by a caller. We term this task 'identifying the best option' (ITBO) and it is explored in two experiments in which the caller's requested information is either present, or absent, at the time when the timetable is presented.

The intrusive effects of unwanted noise have long been a recent cause for concern in the modern work environment. Large-scale surveys administered to employees in the early 1970s found that extraneous noise was cited as one of the most frequent reasons for causing work-related interference [10] with office noise containing speech being rated as more disruptive than other office noises. [11] More recently, it has been suggested that background noise plays a contributory factor in so-called Sick-Building Syndrome in which employees report symptoms of headaches and lethargy which 'disappear' when they leave their office environment. [2] With the increase of office-related and call center jobs, the negative effects of background noise are unlikely to subside. [3] However, it is only relatively recently that studies have demonstrated the detrimental effects of background noise on task performance; [1],[5],[6],[7],[8],[9] whereas this phenomenon has been well documented in the laboratory. [12]

Arguably the most well-researched auditory distraction phenomenon in the laboratory is the irrelevant sound effect (ISE) [13],[14],[15] Essentially it is the poorer performance in a background sound condition compared to a quiet, control condition which, historically, is conducted using a serial recall task. This simple task involves the presentation of a sequence of seven to nine verbal items (e.g., digits or consonants) which then have to be recalled in the order of presentation immediately after the last item, or following a short retention period. During various phases of the task, background sound is presented, which participants are explicitly told to ignore. The ISE can reach up to 30-50%, is seemingly resistant to habituation within an experiment; [16],[17] and between experimental sessions, [18] and only about one-eighth of individuals are impervious to its effect. [19]

Two key factors are vital for the ISE to occur: The degree of acoustical variation between successive items within the sound and the reliance on order information, via sub-vocal rehearsal to successfully complete the focal task. Jones and colleagues demonstrated that for irrelevant speech to disrupt serial recall, there has to be a degree of acoustical variation in such spectral qualities as pitch and timbre. [20] For example, greater disruption was observed with the presentation of a list of letters such as 'n, r, p…' compared with a list that contained just a repeated letter like 'c, c, c, c…'. [21] Thus, impairment has been demonstrated, for example, with speech, non-speech, music, tones and office noise. [9],[10],[11],[12],[13],[14],[22],[23]

The second crucial factor for the ISE to occur was that the primary task must require information to be processed serially or encourage the process of rote rehearsal to maintain order information for successful performance such as in serial recall, free recall and mental arithmetic. [5],[23] Furthermore, the information to be seriated need not be verbal; irrelevant speech disrupted the serial recall of a sequence of locations in which a dot appeared. [24] In contrast, tasks that do not require the use of seriation, such as the missing item task, category recall or reading comprehension, are not impaired by changing-state irrelevant sound. [7],[20],[25],[26],[27]

The current experiments arose from an attempt to apply the laboratory research findings on irrelevant sound to the reality of everyday working life within offices and call centers. As mentioned earlier, it could be argued that call centers would be the most likely office environment to suffer from the effects of irrelevant sound due to the nature of the job; employees in close proximity to each other have to converse with customers via telephones, quite often providing similar information to each other.

Both experiments derived from informal interviews with National Rail enquiry employees. In the course of their job they receive telephone calls from customers who provide information about particular train journeys they wish to go on, such as the train stations they will depart from, arrive at and may pass through, as well as times and dates of the journey and also information about particular amenities on board. From these interviews, employees informed us that this information is used to identify appropriate train journeys for the customer. Thus, the two experiments aimed to recreate the job of providing the most appropriate journey for the customer from their particular information, that is, to 'identify the best option'. Participants were presented with a series of visual requests that contained nine pieces of information regarding train journeys. After encoding each request, participants had to identify four journeys, out of 16, from a timetable. The information was presented visually, as although this type of information would normally be presented through headphones in call centers, we wanted to ensure that any observed effects were the result of interference within memory and not a problem of perceptual registration due to auditory masking. [28]

  Experiment 1 Top

The purpose of Experiment 1 was to explore whether this novel task of identifying the best option from a train timetable of options would be impaired by changing state irrelevant sound. As the task requires receiving the requested information and then identifying the train journey from the timetable, it is possible that the information is memorised serially via the process of rehearsal, in which case it should be vulnerable to impairment by changing state irrelevant sound.



Forty-eight undergraduate students from a university in south Wales participated in return for course credit or a small honorarium. All reported normal vision and hearing and were aged between 18 and 30 years.


The stimuli for the identifying the best option (ITBO) task consisted of 20 customer requests, presented using SuperLab Pro via a Samsung Syncmaster 171S PC, and 20 matching timetables. Both the requests and timetables were divided into two groups, one for each of the two sound conditions. Each of the requests was a paragraph containing a nine pieces of information about a possible train journey; start station, destination station, via station, date, departure time, arrival time, smoking carriage, buffet carriage and student ticket (this was also the order of information for each of the train journeys within each timetable). The information in each request was based upon one of five different conversational templates comprising different orders, thus two per sound condition. For example, 'I'd like a student ticket and wish to travel to Bristol Parkway from Cardiff Central. I need to arrive before 3 p.m. but I can't leave before 11 a.m. I would like to be in the smoking carriage but do not require there to be a buffet carriage'. For each request there was a timetable containing 16 journeys in which only four of them satisfied the information in the request. That is, only four of them were appropriate, or correct, responses. The ordering of information in all the timetables was as mentioned above.

The office noise sound condition was recorded using Sound Forge and mixed using the Sound Edit Pro software package and comprised the following individual sounds: Computer humming, doors opening and closing, typing, photocopier, printer, telephone ring, mobile telephone ring, papers being shuffled, footsteps, knocking at the door and speech. The speech consisted of male and female voices reading short passages of text (30-50 s) about such topics as knitting, ships, seeds, bread making and drums. This contained names of train stations and departure and arrival times. The mix was within the range 65-75 dB (A).


A within-factor (sound: Quiet and office noise) design was used. Participants performed the task once in each of the sound conditions and the order in which the conditions were presented was counterbalanced across participants. Correct identification of journeys was recorded with a score ranging from zero to four for each timetable.


Participants were tested in small groups of up to three and standardized instructions informed them that they were to view a series of visually presented customer requests concerning train journeys. Each request stayed on the screen for 20 s and was replaced by a blank screen for 25 s. Participants were asked to memorize the request and, when the screen was blank, to identify four journeys from the appropriate timetable that matched the information in the request. There were two practice trials followed by two blocks of 10 experimental trials with each experimental block associated with noise conditions.

Results and discussion

For each of the ten trials, within each noise condition, there were four possible correct responses. [Figure 1] shows that performance was better in the quiet, compared to the office noise, sound condition. This was confirmed by a related t-test that revealed that participants were significantly better at identifying the best option in the quiet sound condition, t(47)=−2.59, P<0.05. These findings are consistent with the prediction that if participants were using rehearsal to seriate the information from the requests in order to help them remember the information they needed to identify the best option from the timetable, then performance would be impaired in the office noise condition due to a conflict of processing order information.
Figure1: Mean proportion and standard error of correct identifying the best option performance with 25- second delay

Click here to view

  Experiment 2 Top

Although the disruption observed in Experiment 1 is consistent with the changing-state account of irrelevant sound, Experiment 2 sought to test this more thoroughly by minimizing the amount of rehearsal that participants could engage in. If no impairment was observed following this manipulation, it would provide more evidence for the use of rehearsal in this task. In the laboratory, minimizing rehearsal can be achieved through the implementation of articulatory suppression. [24] That is, participants are instructed to repeat a simple phrase or word (e.g., 'the, the, the…') which prevents them from rehearsing, and consequently processing, the order of information that they wish to recall. Thus, the ISE is drastically reduced using this procedure. However, it could be argued that this would be a rather impractical technique to employ in the work environment and alterations to the task itself may be more practical. One way to minimize the need for rehearsal would be to present the customer's requested information at the same time as the timetable is also present. If this reduces the need for participants to rely on their short-term memory, and thus rehearsal processes, then presenting both the written requests and the timetables concurrently, should produce very little disruption.



Thirty-eight undergraduates students from a university in south Wales participated in exchange for course credit or a small honorarium. All reported normal vision and hearing and were aged between 18 and 30 years.


Materials and presentation were identical to those in Experiment 1. The date information was removed from all trials since it was realized that it did not help in discriminating between journeys.


A within-factor design was adopted with office noise and quiet being the two levels of sound. Presentation of the sound conditions was counterbalanced across the experiment. As in Experiment 1, the correct identification of journeys was measured.


The procedure was identical to Experiment 1 except that participants were informed that they could begin responding as soon as they saw the request.

Results and discussion

A paired t-test showed that there was no difference between the two sound conditions, t(37)=−0.96, P>.05, see [Figure 2]. The lack of a significant difference between the two conditions is consistent with the changing-state account, suggesting that participants did not need to engage in rehearsal to successfully complete the task.
Figure 2: Mean proportion and standard error of correct identifying the best option performance without 25-second delay

Click here to view

  Discussion Top

Two experiments explored the effects of call center noise on a novel laboratory task that mimicked a call center-like task - identifying the best option (ITBO). The task involved selecting the appropriate train journeys from a timetable when presented with a series of requirements (such as departure times and destinations) from a customer whilst ignoring, in one condition, realistic background office sound. In the first experiment the timetable from which participants chose the appropriate journeys was presented after the customer's information had been presented. Results demonstrated that the presence of background office sound significantly impaired performance compared to a quiet, control condition. For the second experiment, the timetable and customer information was presented at the same time resulting in no significant difference between the sound conditions. These findings are consistent with the prediction that participants use rehearsal to seriate the information from the requests in order to help them remember the information they needed to identify the best option from the timetable: Performance is impaired in the office noise condition due to a conflict of processing order information.

When performing a task that requires the participant to engage in rehearsal to retain the order of information, the presence of an acoustically changing background sound causes a significant drop in performance. Much laboratory research regarding this has focused on the irrelevant sound effect (ISE) in which the task is serial recall. [4] However, this effect has been observed with other tasks, such as mental arithmetic; [5],[29] that one might perceive to be more representative of an office-, or call center, style task. The current paper extends this research to another realistic call center, style task- ITBO. This new task demonstrated similar patterns of disruption to those afore-mentioned tasks in that performance was significantly poorer in a changing-state background sound condition compared to quiet (Experiment 1). In a second experiment, when the need for rehearsal was minimized (by allowing participants to identify the appropriate train journeys whilst they viewed the request), no impairment was observed- participants could begin to identify the most appropriate train journey immediately rather than have to wait during which time they relied upon their short-term memory. This latter finding is consistent with studies showing that when rehearsal is prevented or not required, impairment to the focal task does not occur. For example, when items are required to be recalled according to the categories they belong to rather than in serial order, performance is equivalent for the changing-state background and quiet conditions. [9] Further afield, spatial awareness performance using the Blocks World Task, in which participants have to recreate an array of colored blocks, is significantly poorer when they are unable to respond immediately (due to a gray mask being presented for 1 s) compared to when there is no delay. [30] It can be argued that in the masked condition, participants are reliant upon their rehearsal abilities to remember the position and colours of the blocks before they are allowed to recreate the configuration whereas in the unmasked condition, participants can start recreating the configuration immediately without relying on short-term memory. Similarly, it was found that irrelevant speech impaired memory-, but not perceptually based, tasks and this disruption disappeared when memory load was increased. [31]

Theoretically, the results are consistent with the interference-by-process account of the ISE. [32] Where a task involves rehearsal to maintain the order of information, as it does for serial recall, any irrelevant sound that contains changing-state information will impair performance due to the order information arising from the items in the irrelevant sound conflicting with the order of items in the process of rehearsal. This impairment is reduced if either the task does not require seriation [9] or the background sound has little changing-state information. With regard to the latter, this can be achieved by reducing the sound's waveform so that it becomes 'smoother'. For example, installing acoustically treated ceilings can do this but the reverberation time needs to be increased, rather than decreased as these ceilings do, to reach performance levels similar to quiet. [8],[33] Manipulating signal-to-noise ratios, so that the offending noise is masked, can also produce this effect. However, the mask has to be at a substantially higher intensity level to the noise and more realistic levels offer no real help. [28],[34]

Although there are other theoretical accounts of the ISE, we feel that they are less successful in explaining the data reported here. First, Baddeley and colleagues [35] consider the disruption of background speech as evidence for the existence of a phonological storage component within short-term memory. However, a considerable body of evidence exists suggesting that the ISE cannot be accounted for in terms of phonological storage as non-phonological sounds elicit the effect. [6],[14],[36],[37],[38],[39] Both the feature [32] and attentional recruitment accounts [40] place greater emphasis on the power of the irrelevant sound to capture attention away from the primary task, regardless of the processes involved. As such, they would be unlikely to explain why the same irrelevant sound disrupted performance in Experiment 1 but not in Experiment 2 where the need for rehearsal was minimized.

In summary, we report impairment of a novel, call center style task by irrelevant sound and argue that this is due to the mechanism that underpins the ISE- namely a conflict of processing order information. As such it represents a successful exploration into the impact of laboratory phenomenon on real-world tasks and adds to the increasing body of knowledge regarding auditory distraction.

  References Top

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Correspondence Address:
Nick Perham
School of Psychology, University of Wales Institute Cardiff, Cardiff CF5 2YB
United Kingdom
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1463-1741.93308

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