Multitasking

2.4.1 Multitasking Research in Cognitive Science and Psychology

The research on multitasking has a decades-long history in the field of cognitive sciences and psychology. Cognitive psychologists have provided extensive research literature on multitasking, concurrent information processing, task switching (Burgess, 2000; Pashler, 2000) and sequential actions (Carlson & Sohn, 2000).

Multitasking is the ability of humans to handle the demands of multiple tasks concurrently through task switching or interleaving if necessary (Just, Carpenter, Keller, Emery, Zajac & Thulborn, 2001; Lee & Taatgen, 2002). Lee and Taatgen (2002) argued that multitasking behaviours are a product of skill acquisition.

Multiple task situations are faced frequently in daily life. For example, having snacks when watching a TV program, or using multiple information systems simultaneously, for example, checking emails while chatting with friends online.

Neuro-cognitive psychologists have investigated the human brain’s activation mechanism which is associated with multitasking behaviour. They found that when humans conduct multiple tasks at the same time, the activation volume in the cortical systems underlying the execution of tasks decreased compared to that in single task conditions. That is, the cognitive limitation of multiple task performance causes a brain activation decline. They concluded that the productivity level of multitasking performance is accordingly reduced (Just, Carpenter, Keller, Emery, Zajac & Thulborn, 2001). Engineering psychologists found, however, that people may adopt strategies of time sharing or time swapping to manage their multitasking situations effectively. Time sharing is for performing multiple tasks simultaneously, while time swapping is for performing multiple tasks sequentially (Wickens, 1989,

24

1991). Hunt and Joslyn (2000) identified the characteristics of individuals who did well in multitasking and decision making situations under considerable time pressured conditions.

Task switching has been recognised as an important element of multitasking.

Monsell (2003) reviewed the notion of task switching in cognitive science research in which multitasking was considered as switching behaviour from one task to another in rapid succession. The costs to the individual of switching tasks compared to non-switch or task repetition trials are a focus of task switching research in cognitive science. To explain how such multiple tasks and task switching are performed, experimental psychologists have proposed that cognitive executive control systems govern processes including the selection, initiation, execution, and termination of each task (Rubinstein, Meyer, & Evans, 2001). The cognitive executive control system provides a supervisory function controlling other perceptual/motor and cognitive processes when switching from one task to another.

2.4.2 Multitasking Studies in Human Information Behaviour

Spink, Cole and Waller (2008) elucidated information behaviour as a multitasking process. Multitasking information behaviour is emerging as an important information behaviour research area.

In the realm of human information behaviour, the process of seeking information concurrently over time in relation to more than one, possibly evolving, set of information tasks, including shifts in beliefs, cognitive, affective and/or situational states, is called multitasking information behaviour (Spink, Ozmutlu & Ozmutlu, 2002). Multitasking information behaviour includes searching for information related to one information task and then switching to search for items on another information task (Spink, Cole & Waller, 2008).

25

Information scientists have observed the phenomenon of multitasking information behaviour by employing different methodology in a number of different environments, such as library use, database searching and the work environment.

Spink (2004) reported results from a case study exploring the multitasking information behaviour by one information seeker in a public library. The results showed that people engaged in multitasking information behaviours consisting of electronic search, physical library search, serendipity browsing and information task switching in libraries as they seek and search for information on more than one information task. A process of seventeen information task switches over two library visits was identified. Spink, Alvarado-Albertorio, Narayanan, Brumfield and Park (2007) investigated the multitasking information behaviours of ninety-six public library users through diary questionnaires and found that 63.5% of the 96 library users sought information on multiple topics and engaged in multitasking behaviours.

Waller (1997) examined how air crew work groups managed multiple tasks under dynamic and deadline conditions through two field studies. Her model suggested that work groups engaged in information gathering, task prioritisation and resource allocation activities in order to perform multiple tasks. The task characteristics linked to multiple task switching were revealed: (1) the familiarity of the task and its relative difficulty; (2) the source of the task; (3) the task deadline; (4) the status of the task in terms of its potential completion; and (5) the sequence of the task in terms of any interdependence among the tasks being prioritised.

González and Mark (2004) presented results of fieldwork observation of information workers in three different roles: analysts, software developers and managers. They introduced the concept of working spheres to explain the inherent way in which individuals conceptualize and organise their basic units of work. People worked in an average of ten different working spheres and they spent about twelve minutes in

26

a working sphere before they switched to another. Spink and Park (2005) conducted a study investigating business consultants’ multitasking information and non-information task switching and their interplay. They found that information seeking tasks occurred within multitasking and task switching sequences with non-information tasks, including computing and communication tasks. The execution of information seeking tasks often supported or responded to communication or computing tasks.

Spink and Cole (2005) proposed a model of multitasking and task switching information behaviour. They argued that information behaviour may involve a combination of cognitive and physical actions on multiple tasks concurrently or sequentially, including switching between different information tasks. Information seekers have to coordinate a number of factors, including their cognitive state, level of knowledge and understanding of their information problem, into coherent processes of human information seeking, searching, retrieving and usage behaviours. Spink, Park & Cole (2006) argued that multitasking is an essential element of the information behaviour process that must be closely examined, allowed for and facilitated in the design of IR systems.

2.4.3 Multitasking Studies in Web and Information Retrieval

This section investigates how multitasking research has been conducted in information retrieval and Web search studies.

Limited studies have shed light on multitasking information behaviour during Web search and IR sessions. Spink, Ozmutlu and Ozmutlu (2002) originally suggested that IR searches often include multiple topics during a single search session or multitasking search. They found that multitask searching is common human information retrieval behaviour as many IR system users conduct information

27

searching on multiple related or unrelated topics and also switching among the topics. In addition, IR multitasking search sessions are longer than single topic sessions, with a mean of 2.1 topic changes per search session. Their study represents advances in providing a research framework for multitasking during Web and information retrieval.

Subsequently, multitask searching was examined on the Excite and AlltheWeb.com Web search engines. Ozmutlu, Ozmutlu and Spink (2003b) found that multitasking Web searches are noticeable user behaviours, as one tenth of Excite users and one third of AlltheWeb.com users conducted multitasking searches. Additionally, multitasking search sessions with a broad variety of search topics are longer than regular search sessions in terms of queries per session and duration. Koshman, Spink and Jansen (2006) also reported that 11.1% of search sessions over the Vivisimo search engine were multitask searches, including a broad variety of search topics in multitask search sessions.

In 2006, Spink, Park, Jansen and Pedersen (2006) conducted separate studies of two-query search sessions and three or more query search sessions on the AltaVista Web search engine. The degree of multitasking search and information task switching was examined, based on these two sets of search sessions.

Findings included (1) a high degree of multiple topics existed in both two-query sessions (81%) and three or more query sessions (91%); (2) three or more query sessions sometimes contained frequent topic changes; and (3) multitasking was found to be an un-ignored but growing element in Web searching.

Further, Spink, Park and Koshman (2006) investigated multiple information problems ordering which is engaged in Web search by observing forty study participants’ Web searching behaviour. They concluded that information task ordering was affected by the following factors: personal interest, problem

28

knowledge, perceived level of information available on the Web, ease of finding information, level of importance and seeking information on information problems in order from general to specific. Personal interest and problem knowledge were the two major factors affecting multiple information problem prioritisations.

Park (2008) specifically studied human prioritising and coordinating information behaviour among multiple information tasks in a Web information seeking and retrieval context. She found that human prioritising behaviour was affected by multiple factors, such as task attributes, emotions and time. Users’ dynamic Web search interactions existed among the components of their prioritising and coordinating information behaviour. Multiple tasks prioritisation and coordination was operationalised as being composed of the level of each task, cognitive, affective, and temporal and behaviour dimension. The affective factor was considered as an important factor affecting task performance. She stated that how we manage our emotions ultimately yielded successful performance. Her discussion of coordination information behaviour was more on the task level, such as coordinating activities of task switching, and tabbed browsing.

2.4.4 Coordination Viewpoint in Multitasking Research

According to Wickens (1989), multitasking research includes both task characteristics and coordination processes. Multitasking information behaviour is conceptualized as a binding process that works with human coordination behaviours to construct an information behaviour process. It provides a framework for coordinating and integrating the different levels within information behaviour.

Information science researchers such as Spink, Park and Cole (2006) and Spink and Du (2007) incorporated the concept of coordination into multitasking information behaviour. They discussed the role of multitasking and coordination as conceptualizing and binding elements in the integrated information behaviour

29

framework. People coordinate the translation of their information problem(s) by performing search term selection tasks, tactic and strategy tasks, search engine interaction tasks, and relevance judgments. Effective interactive IR must be a successful process of coordinating the switching between related or unrelated tasks.

Multitasking processes, in general, involve a person’s allocation of his/her own scarce cognitive resources among several tasks and the moderating impact of task elements, task processes, and task resources on multiple-task performance. The task coordination research concerns how people coordinate their activities to perform tasks, in particular, decision-making and problem-solving tasks (Waller, 1997). Iani and Wickens (2004) pointed out that the performance of multiple tasks was controlled by cognitive executive processes that enable humans to choose and prioritise tasks, and monitor, interrupt and adjust task performance. Hence, it is necessary to identify how such cognitive executive control processes establish priorities among multiple information tasks and allocate resources to them, thus allowing efficient multiple-task performance.

The following section discusses in detail the research on coordination and its theory, mechanism of coordination, especially the coordination in information retrieval, and ends up with recent studies on cognitive coordination within Web searching context.

30

2.5 Cognitive Coordination