Working memory load but not multitasking eliminates the prepared reflex: further evidence from the adapted flanker paradigm.

The prepared reflex (PR) metaphor (Exner, 1879; Woodworth, 1938) suggests that stimulus-response (S-R) instructions held in working memory (WM) can lead to autonomous response activation without any practice. Cohen-Kdoshay and Meiran (2007) showed flanker compatibility effects immediately following the instructions (First Trials Flanker Compatibility Effect, FTFCE) and also showed that FTFCE was eliminated when participants had to hold an additional novel task rule in mind. They attributed the elimination of the FTFCE to WM load, but did not rule out multitasking and associated increased control demands as a possible alternative explanation. In the present experiment, the authors compared a no-load condition, a load condition involving a secondary task that was changed in every block (thus requiring WM) and a multi-tasking condition involving a secondary that remained the same throughout the experiment. The results show FTFCE without load and in the multi-tasking condition but no FTFCE in the WM load condition, establishing the critical involvement of WM storage capacity in the FTFCE.