The task rule congruency effect in task switching reflects activated long-term memory.

Abstract

Reaction time task rule congruency effects (RT-TRCEs) reflect faster responses to stimuli for which the competing task rules indicate the same correct response than to stimuli indicating conflicting responses. The authors tested the hypothesis that RT-TRCE reflects activated overlearned response category codes in long-term memory (such as up or left). The results support the hypothesis by showing that (a) RT-TRCE was absent for tasks for which there were no response codes ready beforehand, (b) RT-TRCE was present after these tasks were practiced, and (c) these practice effects were found only if the tasks permitted forming abstract response category codes. The increase in the RT-TRCE with response slowness, found only for familiar tasks, suggests that the abstract response category codes may be verbal or linguistic in these cases. The results are discussed in relation to task-switching theories and prefrontal functions.Keywords: task switching, working memory, congruency, practice, prefrontal functions Working memory (WM) and task switching are two core executive functions. Their interrelationships have been studied by means of a variety of approaches. These include examinations of WM load effects on task-switching performance (Baddeley, Chincotta, & Adlam, 2001;Emerson & Miyake, 2003), comparing WM span for tasks with WM span of items (Logan, 2004), individual differences studies (e.g., Miyake et al., 2000), and cognitive theorizing (e.g., Logan & Gordon, 2001;Mayr & Kliegl, 2000;Sohn & Anderson, 2001). The present study suggests an as-of-yet unrecognized link between these two functions by focusing on a highly replicable but poorly understood phenomenon from the task-switching literature, the task rule congruency effect (TRCE). In the remainder of the introduction, we review the literature on the TRCE and suggest a WM account for it. The experiments reported in this article provide additional crucial evidence that support our account.Task Switching and the TRCE Researchers interested in task control often use the taskswitching paradigm. The rationale for this choice is straightforward. Performance in stable conditions without task switching can be done in an "automatic pilot" mode, with little need for active control. This luxury is unavailable when there are frequent task switches. Most of the research has concentrated on the various costs associated with task switching (Fagot, 1994;Jersild, 1927; Monsell & Driver, 2000). However, additional highly replicable effects have also been found, and understanding their basis is likely to shed light on how control is accomplished (cf. Altmann, 2003). In the present work, we concentrate on the TRCE. This effect is among the most reliable found in task-switching experiments, yet relatively little work has been done to unravel its causes.To the best of our knowledge, Sudevan and Taylor (1987) were the first to demonstrate the TRCE in the context of task switching. The participants in their experiments responded to single digits and switched between two classification t...

Instruction-based task-rule congruency effects.

“…RTs and accuracies were each subjected to a 3 =4.52, r²=.54, no such effect was present in the Verbal Diagnostic Task condition, t(16)= 1.12, p>.13, r²=.08. In other words, the error rates were thus only partly in line the RT-data, which might suggest that with respect to the task-rule congruency effect, RT and error-rates are elicited by different processes (e.g., Meiran & Kessler, 2008). Yet, in view of the absence of an effect in this one contrast, it would be premature to draw conclusions at this stage…”

“…We were especially interested if such task-sets could trigger responses when being irrelevant in the context of another task. Because previous research (Cohen-Kdoshay & Meiran, 2007;2009;De Houwer et al, 2005;Meiran & Kessler, 2008;Waszak et al, 2008;Wenke et al, 2007;2009) indicate that responses in instruction-based task-sets are represented in terms of conceptual codes (e.g., -left‖ or -right‖) without further specification. Experiment 2 showed that tasksets eliciting such effects are formed only when participants intend to enact the instructed task.…”

“…In view of these accounts, an alternative explanation for our results could be that the instruction-based task-rule congruency effect is also based on S-R associations in active long-term memory. This hypothesis could in part be inspired by the account of Meiran and Kessler (2008) who argued that for preexisting response codes (e.g., the codes ‗left' and ‗right' as used in the present study), the executionbased task-rule congruency effect shows up after minimal practice because these codes are highly accessible in active long-term memory. Hence, encoding S-R mappings -for instance accompanied by covert mental practice -may have the same outcome than the actual execution of S-R mappings, namely the formation of S-R associations in active long-term memory.…”

“…This explanation is at odds with accounts of the task rule congruency effect observed when participants frequently switch between tasks. As outlined in the introduction, there is evidence that such task-rule congruency effect is triggered by S-R associations that INSTRUCTION-BASED TASK RULE CONGRUENCY EFFECTS 26 are represented in active long-term memory and is not related to the interference between task-sets (Meiran & Kessler, 2008;Kessler & Meiran, 2010;Kiesel et al, 2007;Wendt & Kiesel, 2008;Yamagushi & Proctor, 2011). In view of these accounts, an alternative explanation for our results could be that the instruction-based task-rule congruency effect is also based on S-R associations in active long-term memory.…”

“…For example, Kiesel et al (2007) demonstrated that the task-rule congruency effect was much stronger for stimuli that were frequently encountered in the context of the now-irrelevant task compared to stimuli that were not previously encountered INSTRUCTION-BASED TASK-RULE CONGRUENCY EFFECTS 5 in the context of the now-irrelevant task. Furthermore, Meiran and Kessler (2008) demonstrated that for novel and arbitrary S-R mappings, practice is needed in order to obtain the task-rule congruency effect. However, for S-R mappings referring to accessible and preexisting response codes such as ‗up' or ‗down', the task-rule congruency effect immediately shows up.…”