Two non‐verbal cognitive systems, an approximate number system (ANS) for extracting the numerosity of a set and a parallel individuation (PI) system for distinguishing between individual items, are hypothesized to be foundational to symbolic number and mathematics abilities. However, the exact role of each remains unclear and highly debated. Here we used an individual differences approach to test for a relationship between the spontaneously evoked brain signatures (using event‐related potentials) of PI and the ANS and initial development of symbolic number concepts in preschool children as displayed by counting. We observed that individual differences in the neural signatures of the PI system, but not the ANS, explained a unique portion of variance in counting proficiency after extensively controlling for general cognitive factors. These results suggest that differences in early attentional processing of objects between children are related to higher‐level symbolic number concept development. Event‐related brain potentials provide evidence that parallel individuation (PI) of objects is related to individual differences in counting development in preschool‐aged children. The relationship between PI and counting holds after controlling for general cognitive and linguistic abilities. Both quantitative and qualitative differences were observed in the neural signatures of numerical processing between developing and proficient counters, but need to be followed up with targeted experiments to be better understood.