When: 12 noon
Two hundred SFSU students (55% bilingual) completed three standard switching tasks: color-shape, letter-number, and living-size. We replicated Friedman, et al.’s  report of significant correlations between the switching costs derived from each task, thus verifying that the three tasks show convergent validity as measures of switching ability. The substantial level of convergent validity felicitously contrasts with the dismal levels of convergent validity for common measures of inhibitory control . This sets the stage for a strong and compelling test for bilingual advantages in executive functioning (EF) as advocated by Paap and Greenberg  in that multiple measures of the same component of EF (switching in this case) can be derived for both language groups. If the results are consistent across the tasks this severely attenuates the chances that they are task specific. There were no differences between the groups of bilinguals and monolinguals in any of the three tasks for either mixing costs (mean RT on the repeat trials of the mixed block minus mean RT in the pure single-task blocks) or switching costs (mean RT on switch trials minus mean RT on repeat trials). These null results contrast with the bilingual advantage in switching costs reported by Prior and MacWhinney , but are completely consistent with the null results reported in six recent experiments using large numbers of bilinguals and monolinguals [3, 2, 5]. The cumulative evidence overwhelmingly favors the conclusion that there are no differences between bilinguals and monolinguals in switching ability. Participants also responded to two category fluency probes (musical instruments and vegetables), two verbal fluency probes (“F” and “A”), and two probes to alternate between two categories (e.g., furniture and fruit) and between two letters (e.g., “S” and “T”). Consistent with previous research monolinguals generated more correct responses in these tasks. Of more interest is the new finding that none of these verbal fluency tasks correlate with any of the measures of switching ability. These findings do not align with the clinical and neuroimaging evidence suggesting that verbal ability may be more strongly reflected in category than in letter fluency scores, and that, conversely, executive functioning may be more strongly reflected in letter fluency scores .
 Friedman, N. P, Miyake, A., Individual differences in executive functions are almost entirely genetic in origin. Journal of Experimental Psychology: General, 137(2), 201-225, 2008
 Paap, K. R., & Sawi, O. Bilingual advantages in executive functioning: problems in convergent validity, discriminant validity, and the identification of the theoretical construcs. Frontiers in Psychology, 5:962, 1-15, 2014.
 Paap, K. R., & Greenberg, There is no coherent evidence for a bilingual advantage in executive processing. Cognitive Psychology, 66, 232-258, 2013.
 Prior, A., & MacWhinney, B. Bilingualism, 13, 253-262, 2010.
 Hernández M., Martin, C. D., Barceló, F., & Costa, A. Where is the bilingual advantage in task-switching? Journal of Memory and Language, 69, 257-276, 2013.
 Shao, Z., Jans Predictors of verbal fluency performance in older adults. Frontiers in Psychology, 5:772, 1-10, 2014.