Following the Tune: Divergent Processing Strategies for Auditory Sequence Recognition in Humans and a Songbird

Deriving sequential information from complex sounds is a challenge for auditory systems, yet it remains 9
unclear whether humans and nonhuman species integrate concurrent cues or prioritize a single dimension 10
when processing multidimensional input. We investigated shared constraints and species-specific 11
predispositions in processing strategies across humans and zebra finches using an identical operant 12
conditioning paradigm with complex-tone sequences. By presenting probe stimuli that selectively 13
preserved or disrupted either pitch or formant trajectory, we quantified these strategies. We show that 14
zebra finches employ an additive integration strategy, treating pitch and formant trajectories as 15
complementary components of a unified auditory pattern. In contrast, humans exhibit a dominant reliance 16
on pitch. Critically, experience further modulated this bias, revealing cross-dimensional abstraction: 17
trained listeners recruited secondary cues to preserve learned relational structure when pitch was 18
unreliable. These findings imply a cross-species divergence in auditory representation, suggesting that 19
human auditory processing is shaped by an interplay of species-specific priorities and experience- 20
dependent functional substitution.