 Nevertheless, issues about the relationship between sound and the thing source (namely, sound and the material object which produces it) and about how we hear both the objects that produce sounds, and the relation between objects and sounds still have to be fully worked out within both views. As a starting point to develop an account on the perception of sound sources or, at least, of some aspects of the thing source, Di Bona (2017) proposes an argument for the perception of a specific characteristic of human voices. She offers an account of how a certain feature of the sound source when the source is the human voice is perceivable. Di Bona focuses on gender and engages with the debate on the admissible content of auditory experience, which has been mostly developed within the field of visual perception, and argues for a “rich” view of the auditory experience. This view is defended by means of the method of contrast applied to a case of auditory adaptation to human voices. The idea is that we hear not only the low-level auditory properties of pitch, timbre, and loudness but also the high-level property of gender, that is, the property commonly referred to as being a female voice or a male voice. This high-level property displays adaptational effects and, given that displaying these effects for a property is a clear mark that this property is perceivable, then we can conclude we hear gender properties instantiated by human voices. O’Callaghan (2011b) also engages with the debate on the admissible content of auditory perception, endorsing a more restricted view on the content of audition. He focuses on speech perception and argues that we do not hear the semantic properties of voices (which can also be seen as properties of sound sources, of voices) since what is auditory perceivable are, instead, the phonological properties.