The architecture of the numerical cognition system is currently not well understood, but at a general level, assumptions are made about two core components: a quantity processor and an identity processor. The quantity processor is concerned with accessing and using the stored magnitude denoted by a given digit, and the identity processor is concerned with recovery of the corresponding digit's identity. Blanc-Goldhammer and Cohen (Journal of Experimental Psychology: Learning, Memory, and Cognition, 40, 1389-1403, 2014) established that the recovery and use of quantity information operates in an unlimited-capacity fashion. Here we assessed whether the identity processor operates in a similar fashion. We present two experiments that were digit identity variations of Blanc-Goldhammer and Cohen's magnitude estimation paradigm. The data across both experiments reveal a limited-capacity identity processor whose operation reflects cross-talk with the quantity processor. Such findings provide useful evidence that can be used to adjudicate between competing models of the human number-processing system.
