Strategic capacity sharing between two tasks: evidence from tasks with the same and with different task sets

Abstract

The goal of the present study was to investigate the costs and benefits of different degrees of strategic parallel processing between two tasks. In a series of experiments with the dual-task flanker paradigm, participants were either instructed to process the tasks serially or in parallel, or--in a control condition--they received no specific instruction. Results showed that the participants were able to adjust the degree of parallel processing as instructed in a flexible manner. Parallel processing of the two tasks repeatedly led to large costs in performance and to high crosstalk effects compared to more serial processing. In spite of the costs, a moderate degree of parallel processing was preferred in the condition with no specific instruction. This pattern of results was observed if the same task set was used for the two tasks, but also if different ones were applied. Furthermore, a modified version of the central capacity sharing (CCS) model (Tombu and Jolicoeur in J Exp Psychol Hum Percept Perform 29:3-18, 2003) was proposed that accounts also for crosstalk effects in dual tasks. The modified CCS model was then evaluated by fitting it successfully to the present data.

Working memory capacity and dual-task interference in picture naming

“…Kahneman, 1973;Kondo et al, 2004;Logan & Gordon, 2001;Meyer & Kieras, 1997a, 1997bNavon & Miller, 2002;Tombu & Jolicoeur, 2003). The assumption that dual-task performance is not constrained by a structural responseselection bottleneck is supported by several findings (e.g., Fan et al, 2012;Hübner & Lehle, 2007;Israel & Cohen, 2011;Kahneman, 1973;Karlin & Kerstenbaum, 1968;Lehle & Hübner, 2009;Leonhard & Ulrich, 2011;Logan & Gordon, 2001;Meyer & Kieras, 1997a, 1997bNavon & Miller, 2002;Pannebakker et al, 2011;Schvaneveldt, 1969;Szameitat et al, 2002Szameitat et al, , 2006Tombu & Jolicoeur, 2003). For example, there is evidence that the magnitude of dual-task interference can be eliminated with practice (e.g., Schumacher et al, 1999Schumacher et al, , 2001, but see Ruthruff et al, 2006;Van Selst et al, 1999) or by increasing the number of short SOAs in an experimental block of trials (Miller et al, 2009).…”

“…Meyer et al, 2003) at short compared to long SOAs. Alternatively, these RT1 effects may occur when central capacity is shared between the Task 1 and Task 2 processes (e.g., Kahneman, 1973;Lehle & Hübner, 2009;Navon & Miller, 2002;Tombu & Jolicoeur, 2003).…”

“…If the semantic interference effect arises before response selection in picture naming (e.g., during perceptual and conceptual processing of the picture), the effect may be absorbed while response selection in the tone discrimination task is taking place and picture naming waits in queue. Consequently, the semantic interference effect will disappear in concurrent task performance, as empirically observed by Dell'Acqua et al and Ayora et al In contrast, if the semantic interference effect arises in lexical response selection (e.g., Abdel Rahman & Melinger, 2009;Hantsch et al, 2005;Levelt et al, 1999;Roelofs, 1992Roelofs, , 2003Starreveld & La Heij, 1996), the effect should not have been absorbed according to the response-selection bottleneck account (Pashler, 1994(Pashler, , 1998Pashler & Johnston, 1989), contrary to what Dell'Acqua et al and Ayora et al observed. However, although very influential, the assumption of a structural response-selection bottleneck is debatable (e.g., Fan et al, 2012;Hübner & Lehle, 2007;Israel & Cohen, 2011;Kahneman, 1973;Karlin & Kerstenbaum, 1968;Lehle & Hübner, 2009;Leonhard & Ulrich, 2011;Meyer & Kieras, 1997a, 1997bMiller et al, 2009;Navon & Miller, 2002;Pannebakker et al, 2011;Schumacher et al, 1999Schumacher et al, , 2001Schvaneveldt, 1969;Szameitat et al, 2002Szameitat et al, , 2006Tombu & Jolicoeur, 2003). According to alternative accounts of dual-task performance, response selection for two tasks may occur in parallel depending on the strategic choice of participants concerning the amount of overlap between tasks (cf.…”

Locus of semantic interference in picture naming: Evidence from dual-task performance.

“…For example, the effect of practice on the magnitude of the dual-task interference is also different across studies (e.g., Karlin & Kestenbaum, 1968;Ruthruff, Johnston, Van Selst, Whitsell, & Remington, 2003;Schumacher et al, 2001;Van Selst & Jolicoeur, 1997;Van Selst, Ruthruff, & Johnston, 1999). These and other findings challenge the assumption of a structural response-selection bottleneck in dualtask performance (e.g., Hübner & Lehle, 2007;Israel & Cohen, 2011;Karlin & Kestenbaum, 1968;Lehle & Hübner, 2009;Leonhard & Ulrich, 2011;Meyer & Kieras, 1997;Miller et al, 2009;Navon & Miller, 2002;Pannebakker et al, 2011;Schumacher et al, 1999Schumacher et al, , 2001Schvaneveldt, 1969;Szameitat, Schubert, Müller, & Von Cramon, 2002;Szameitat, Lepsien, von Cramon, Sterr, & Schubert, 2006;Tombu & Jolicoeur, 2003). Although under the strategic bottleneck account (Meyer & Kieras, 1997;Piai et al, 2011;Roelofs, 2007Roelofs, , 2008a, a responseselection bottleneck is optional rather than obligatory (i.e., response selection in Tasks 1 and 2 may, in principle, occur in parallel), the present findings suggest that participants seem to have a very strong preference for not overlapping responseselection processes in dual-task performance.…”

New perspectives on human multitasking

“…We also know that multitasking costs are modulated by different factors, such as for instance, by the time offered for the tasks to be prepared (Altmann, 2004;Hoffmann, Kiesel, & Sebald, 2003;Koch, 2001;Meiran, 1996;Poljac, de Haan, van Galen, 2006) or by task order (Hirsch, Nolden, & Koch, 2017;Luria & Meiran, 2003;Szameitat, Lepsien, von Cramon, Sterr, & Schubert, 2006;Töllner, Strobach, Schubert, & Müller, 2012). In addition to these examples of task-related factors, the field has informed us that also individual differences play a critical role, such as age (Cepeda, Kramer, & Gonzalez de Sather, 2001;Kray & Ferdinand, 2014;Maquestiaux, Hartley, & Bertsch, 2004;Reimers & Maylor, 2005) or one's own individual multitasking style (Lehle & Huebner, 2009;Miller, Ulrich, & Rolke, 2009;Reissland & Manzey, 2016).…”