Is the auditory system cognitively penetrable?

According to the hierarchical model of sensory information processing, sensory inputs are transmitted to cortical areas, which are crucial for complex auditory and speech processing, only after being processed in subcortical areas (Hickok and Poeppel, 2007; Rauschecker and Scott, 2009). However, studies using electroencephalography (EEG) indicate that distinguishing simultaneous auditory inputs involves a widely distributed neural network, including the medial temporal lobe, which is essential for declarative memory, and posterior association cortices (Alain et al., 2001; Squire et al., 2004). More recent studies have even demonstrated plasticity of auditory signals as low as the brainstem (Suga, 2008). Collectively, studies suggest that the functional architecture of perceptual processing involves primarily top-down modulation (Suga et al., 2002; Gilbert and Li, 2013; Chandrasekaran et al., 2014). Top-down influences exerted throughout the auditory systems (Lotto and Holt, 2011) include: memory (Goldinger, 1998)1, attention (Choi et al., 2014), which has been found to modulate auditory encoding in the cochlea, a subcortical area (Maison et al., 2001), (prior) knowledge of syntax or words (Ganong, 1980; Warren, 1984)2, and experiencebased expectations pertaining to the speaker’s accent (Deutsch, 1996; Deutsch et al., 2004; Irino and Patterson, 2006), gender (Johnson et al., 1999), and vocal folds or tract (Irino and Patterson, 2002; Patterson and Johnsrude, 2008). While a great deal has been written about the issue of cognitive penetrability in the case of vision, audition has received almost no attention. For example, a corresponding body of evidence for topdownmodulation in vision has been used to undermine the Cognitive Impenetrability Thesis (CIT) (see Macpherson, 2012; Siegel, 2012; Wu, 2013; Cecchi, 2014). Brogaard and Gatzia (in press) have argued that top-downmodulation on visual processes involving prior-knowledge, experience based expectation, or memory do not threaten the CIT, even after acknowledging that such influences are cognitive in nature (see also Pylyshyn, 1999; Raftopoulos, 2001). The reason is that such topdown influences, although cognitive in nature, are distinct from discursive thoughts that stand in a semantically-coherent relation to the phenomenology or content of experience, for instance, thoughts proceeding by argumentation or reasoning rather than by intuition or implicit hypothesis internal to the visual system3. If we insisted that instances of top-down modulation be counted as instances of cognitive penetration, the debate about cognitive penetrability would be trivial and, hence, unmotivated since studies clearly indicate that such top-down modulation in visual (or auditory) perception is extensive. A similar argument can be made in the case of audition.