Deaf-gain is defined as "a reframing of 'deaf' as a form of sensory and cognitive diversity that has the potential to contribute to the greater good of humanity." (H-Dirksen Bauman, 2009)
The term Deaf-Gain was coined by U.K. artist Aaron Williamson.
The deconstructive idea of "deaf-gain" contrasts with the old phonocentric definition of the term "hearing loss" and its attitude of "a loss".
It questions the "bioethical values of biodiversity, cultural diversity, cognitive diversity and other contributions to the diversity of humanity." (Bauman)
On the biological level, the advantages are sight (sharper vision, larger peripheral vision, etc), mental imagery (rotation, etc.), and facial recognition.
On the cultural level, the benefits are the knack of communicating with other people of different languages. Environmental design (known as "Deaf Space") is contributed in the eye of Deaf. Film (cinematic techniques, etc.) and poetry are also contributed in the eye of Deaf.
On the linguistic level, sign language brings significant ideas and theories to linguistics about the nature of language.
In hard science, neuroscience studies bring insights about the nature of language, in which language is not central to speech. In neuroscientist Dr. Petitto's words, the brain cannot tell the difference between hands and lips when it comes to language.
Deaf people are an important part of biodiversity as well as cultural diversity as a cultural-linguistic group for their significant contributions.
Related post: Deaf Lens: a cinematographic perspective of Deaf.