For over 20 years, researchers have investigated syntactic priming of transitives by measuring the frequency of sentence choice. These studies have shown syntactic priming for passives but weaker or absent syntactic priming for actives (e.g. [1],[2]). Until recently very few studies have reported syntactic priming by measuring reaction times of language production and none of these studies included transitive sentences. We previously found syntactic priming of both active and passive Dutch transitives in speech onsets, and interestingly the effect appeared to be stronger for actives than passives [3][4]. In order to explain the discrepancy between our results and other results reported in the literature, we hypothesized that there is a ceiling effect in the frequency of using an active transitive (in general about 94% of produced transitives are actives) but not in the speed of producing one. To confirm this hypothesis we conducted a syntactic priming experiment with a picture description task measuring both reaction times and the frequency of occurrence on the same trials. This way we could exclude the alternative explanation that the discrepancy in results is caused by differences in design or stimuli. The results of this experiment show syntactic priming effects for passives and not for actives in the frequency of occurrence (in line with the literature). However, the reaction times of producing these sentences do show syntactic priming for actives and these effects appear to be even stronger than for passives (in line with our previous data). In conclusion, our results suggest that measuring the frequency of occurrence is not enough to get a complete picture of syntactic priming. Measuring reaction times in addition to the frequency of occurrence could provide us with a more complete picture. References [1] Bock, K., & Loebell, H. (1990). Framing sentences. Cognition, 35, 1-39. [2] Hartsuiker, R. J., & Kolk, H. H. J. (1998). Syntactic persistence in Dutch sentence production. Language and Speech, 41, 143-184. [3] Menenti, L., Segaert, K., & Hagoort, P. (2008). Repetition suppression for syntax and semantics: overt speech in fMRI. Society for Neuroscience, Washington DC. [4] Segaert, K., Menenti, L., & Hagoort, P. (2009) Scanning speech with fMRI: Short and long term priming of syntax and verbs, CUNY conference on human sentence processing, Davis, CA.