The shape of attention reflects flexible filtering of natural speech modulations

Perception requires more than passive sensing; it involves prioritizing features relevant to cognitive goals, guided by selective attention. Natural stimuli, such as speech, involve spectrally entangled features, posing demands on attentional mechanisms. A central question is whether attention amplifies all features of the selected input or instead reshapes how stimulus information is represented according to the listener's goal. Here, we recorded EEG while participants performed comprehension or identification tasks on identical continuous speech in noise. To characterize speech cortical representations, we introduce the Modulation Response Function (MRF), a neural analogue of the acoustic modulation spectrum that characterizes cortical sensitivity to spectrotemporal modulations. MRFs revealed distinct relative attentional strategies: comprehension enhanced formant modulations supporting intelligibility, whereas identification emphasized pitch cues linked to voice presence. These differences remained stable across time and listening difficulty, consistent with flexible, goal-dependent attentional filtering. These findings refine future models of how cognitive goals shape speech representations.