Fig 4. DORA network power spectrum plot of the Word List, Phrases, and Jabberwocky conditions.

For Word List, an increase in firing only occurred at the 4 Hz range, corresponding to firing of nodes coding for words. Lack of firing at other frequencies indicates that no hierarchical representations were processed in the Word list condition. In the Phrases condition, there was an increase in power at 2 Hz and 4 Hz, indicating that units coding words and units coding phrases were active during the processing of this condition. No sentence units were active. In the Jabberwocky condition, there was an increase at 1, 2, and 4 Hz range, similar to the pattern seen for grammatical sentences, indicating that hierarchical representations were indeed activated. See Fig 5 for a comparison of activation across the propositions in the model's long-term memory between Jabberwocky and Grammatical sentences. Data from the simulations and the code to run them are available at https://osf.io/eb2vp/ and https://github.com/AlexDoumas/dingetal_sent.