Individual differences in picture naming speed: Contribution of executive control

Speakers clearly differ in how quickly they can retrieve words from the mental lexicon, but little is known about the sources of this variability. The present study investigated the relationship between speakers’ executive control abilities and their speed of picture naming. In two experiments, adult speakers of British English named line drawings of objects and actions. Three main components of executive control - updating, shifting of attention, and inhibiting - were assessed using the operation-span, number-letter shifting, and stop-signal task, respectively (see Myake et al.,2000 ). Reaction times (RT) to action and object pictures were highly correlated. Ex-Gaussian analyses of the RT distributions showed that the speakers’ updating scores correlated with the tau parameter of the RT distributions, i.e. predicted the proportions of slow responses in action and object naming. The inhibiting scores correlated with the mean RTs, whereas the scores obtained in the number-letter shifting task were uncorrelated to the RTs. These results indicate that the executive control abilities of updating and inhibiting contribute to the speed of naming objects and actions. Theories of word production may require modification to take account of these findings