The Cost of a Voluntary Task Switch

Abstract

Task-switching paradigms are widely used to study executive control. However, standard paradigms may not require active control to switch tasks. We examined voluntary task switching by having subjects choose which task to perform on a series of bivalent stimuli. Subjects performed parity or magnitude judgments on single digits. Instructions were to perform the two tasks equally often and in a random order. The response-to-stimulus interval (RSI) was either 100 or 1,000 ms, manipulated between blocks. Task alternations were slower than task repetitions, and this switch cost was greater at the short RSI than at the long RSI (310 and 94 ms, respectively). Additionally, subjects produced more task repetitions than expected if the tasks were performed in a random sequence. These results show costs associated with a voluntary task switch, when subjects must actively control the choice of the task to be performed.

A chain-retrieval model for voluntary task switching

“…Instructions of Arrington and Logan (2004) were used. In each condition, participants received one practice block and four blocks of 64 test trials each.…”

“…For that reason, we focus on testing how well the presented model can account for voluntary task selection and independent-event selection performed by participants in experimental settings. In a first study, the model is applied to data of 17 participants in voluntary task switching based on the standard procedure (Arrington & Logan, 2004). In a second study, the model is applied to data of 80 participants in a voluntary task switching study based on the double registration procedure (Arrington & Logan, 2005).…”

“…This experiment used the standard method of voluntary task switching, where one single key-press informs about the task selected and the categorization of the target (Arrington & Logan, 2004. This version of the procedure has been shown to be very sensitive to bottom-up triggered repetitions (Demanet et al, 2010;Mayr & Bell, 2006).…”

“…Behavioral flexibility, however, also involves the possibility to choose voluntarily for a particular course of action or for a particular goal. Such goalselection or task-selection processes can be examined with the voluntary task switching (VTS) procedure (Arrington & Logan, 2004. This procedure seems to tap into the same behavioral mechanisms that are studied in the traditional task-switching procedures as testified by the finding that task switch costs are driven by top-down (Arrington & Logan, 2005;Mayr & Bell, 2006) as well as bottom-up factors (Arrington, 2008;Arrington & Rhodes, 2010;Mayr & Bell, 2006;Yeung, 2010).…”

Voluntary Task Switching: Chasing the Elusive Homunculus.

“…Open questions remain about this repetition bias and the influence of external stimuli on the choice behavior. The stimulus displays in Arrington and Logan's (2004a) study were extremely sparse, consisting of the single target digit presented on a blank screen. Experiments 1-3 introduce variability in the stimuli external to the task to examine whether subjects will allow stimuli in the task environment to drive the choice process.…”