Opposing perspectives of language processing either emphasize serial order or hierarchal structure (Frank et al., 2012; Yang et al., 2017), while a third perspective unifies seriality and hierarchy in the view that hierarchical organizations emerge from simultaneous serial activity on different time scales just as in other domains (Langacker, 2020). With the aim to contribute to these discussions, we replicated and extended an earlier study (Cohn et al., 2014) with adults in which ERPs patterned with the hierarchical structure of picture sequences (comic strips) and not with their serial order. In the present ERP study with children, we used both Cohn et al.’s picture paradigm and a novel verbal paradigm (so far not used with adults) that was constructed to correspond to the picture paradigm. More specifically, interruptions (prolonged silent pauses) were inserted within or between clauses of auditorily presented sentences to correspond to interruptions (blank panels) within or between constituents of picture sequences. Preliminary results for 10-12-year-old children (N = 15) revealed an expected anterior negativity (500-700 ms) that varied with placement of interruptions of picture sequences but the previously reported effect of this manipulation on the P600 amplitude was not replicated. Importantly, however, the amplitude of the anterior effect varied with the serial order of the interruptions, in contrast to previous results for adults where the amplitude varied with the hierarchical structure (i.e., an increased anterior negativity, 500-700 ms, to within constituent interruptions compared to between constituent interruptions). This pattern of results was identical in the novel verbal paradigm. That is, in children, interruptions of sentences elicited an anterior negativity that varied in amplitude with the serial order of the interruptions rather than with the hierarchical structure, while the P600 amplitude was not affected by placement of interruption. These combined results suggest that children’s processing relies on seriality rather than hierarchy in both sentences and picture sequences. This is in line with domain general perspectives of language processing that regard serial order as fundamental and hierarchical structures as emerging organization. We suggest further investigations to answer when in development hierarchical processing emerges in each and both of the domains.