Since Gisela Granena’s influential work, LLAMA D v2, a sound recognition subtest of LLAMA aptitude tests, has been used as a measure of implicit learning aptitude in second language acquisition research. The validity of this test, however, is little known and the results of studies with this instrument have been somewhat inconsistent. In this study, we tested the hypothesis that researchers’ variable test instructions are the source of the inconsistent results. One hundred fourteen English monolinguals were randomly assigned to take LLAMA D v2 under one of three test instruction conditions. They also completed two implicit aptitude tests, three explicit aptitude tests, and a sound discrimination test. The results showed that, regardless of the type of test instructions, LLAMA D scores did not align with implicit aptitude test scores, indicating no clear evidence of the test being implicit. On the contrary, LLAMA D scores were negatively associated with scores on one implicit aptitude test, the Serial Reaction Time (SRT) task, but only in the condition where the instructions drew participants’ focal attention to the stimuli. This negative association was interpreted as focal attention working against learning in the SRT task. Implicit learning aptitude may be the degree to which one is able to process input without focal attention.