Cognitive neural mechanisms of tonal patterns and semantic processing in poetry

Music has long been considered the soul of poetry, a reflection of their shared origins across diverse cultural contexts. Historically, poetry and music were inseparable, with poems frequently performed through songs. As the arts evolved, however, poetry gradually shifted toward a focus on literal meaning, shedding its musical accompaniment and entering an era of “words without tunes.” Yet the musical essence of poetry endures, embedded in the rhythmic, tonal, and melodic qualities of language itself. In classic Chinese poetry, tonal patterns serve as a defining prosodic feature, shaping both the rhythmic flow and the musical character of a poem. The present study investigated the neural mechanisms underlying tonal patterns in classic Chinese poetry and their interaction with semantic processing. Forty-eight participants with extensive experience reading classic Chinese poems took part in an electroencephalography (EEG) experiment. They were presented with four versions of classic Chinese poems in a pseudo-random order: (1) semantically congruous with regular tonal patterns (S+T+), (2) semantically congruous with irregular tonal patterns (S+T−), (3) semantically incongruous with regular tonal patterns (S−T+), and (4) semantically incongruous with irregular tonal patterns (S−T−). Each participant viewed 100 experimental stimuli and additional 40 filler stimuli. After reading each poem, participants rated the reasonableness of both its semantics and tonal patterns. Throughout the experiment, both behavioral responses and EEG data were recorded. Accuracy rates and event-related potentials (ERP) were analyzed using linear mixed-effects models via the lmerTest and emmeans packages in the R, and EEG preprocessing was conducted using the MNE software package in Python. Accuracy results showed that participants performed best on the S+T+ condition, whereas congruous poems with irregular tonal patterns (S+T−) yielded the lowest accuracy. ERP analyses revealed that tonal patterns exerted a continuous influence on both early and late stages of poetry reading. Specifically, in the P200 window, an interaction between tonal patterns and scalp region indicated that irregular tonal patterns elicited larger P200 amplitudes at anterior and central sites. In the N400 time window, a significant interaction between semantics and tonal patterns emerged: semantically incongruous lines produced a more pronounced negative component than congruous lines when tonal patterns were regular, whereas this semantic difference diminished under irregular patterns. Furthermore, in the LPC time window, irregular tonal patterns evoked larger positivities for semantically incongruous poems, while semantic congruity eliminated the tonal pattern effect altogether. Finally, deep learning models trained on the EEG data reliably distinguished among the four experimental conditions, indicating robust neural signatures associated with the combined tonal-semantic processing. In summary, the current findings underscore the significant impact of tonal patterns on the reading of classic Chinese poetry. Irregular patterns modulated phonological representation at early stages and constrained semantic comprehension at later stages. Supporting the neurocognitive poetics model (NCPM) of literary reading, these results shed light on how prosodic elements and semantic meaning dynamically interact over time during poetic processing.