“…The cognitive factor investigated in the present study, working memory, has been found to be a robust predictor of second language learning (for recent reviews, see Wen, 2016;Wen et al, 2017;Singleton, 2017), above all in studies on vocabulary and grammar learning (Sanz, Lin, Lado, Stafford & Bowden, 2014). However, few studies (Gilabert & Muñoz, 2010;Guara-Tavarés, 2013;Kormos & Safar, 2008;Kormos, 2012b;Kormos & Trebits, 2011;Mota, 2003;Tagarelli, Ruiz, Moreno & Rebuschat, 2016;Zalbidea, 2017) have examined the relationship between working memory and different dimensions of language performance, namely, complexity (both structural and lexical), accuracy and fluency (henceforth, CAF). Furthermore, these studies have come to mixed results, as will be discussed in more detail below, and they often address only one or two dimensions, with only some studies including the four dimensions of linguistic performance.…”