English: Example of the Posner letter-matching task (PLM) adapted from Figure 2 of Plomin & Spinath (2002).^[1] In the PLM, a correct response (indicated by a checkmark) in the physical identity (PI) condition requires visual discrimination only, while the name identity (NI) condition requires additional access to long-term memory storage. The difference score (indicated by RT_NI – RT_PI) between RTs in the two conditions is suggested as an index of rate of long-term memory retrieval.