This effect may be experienced when a video of one phoneme's production is dubbed with a sound-recording of a different phoneme being spoken. Often, the perceived phoneme is a third, intermediate phoneme. As an example, the syllables /ba-ba/ are spoken over the lip movements of /ga-ga/, and the perception is of /da-da/. McGurk and MacDonald originally believed that this resulted from the common phonetic and visual properties of /b/ and /g/. Two types of illusion in response to incongruent audiovisual stimuli have been observed: fusions ('ba' auditory and 'ga' visual produce 'da') and combinations ('ga' auditory and 'ba' visual produce 'bga'). This is the brain's effort to provide the consciousness with its best guess about the incoming information. The information coming from the eyes and ears is contradictory, and in this instance, the eyes (visual information) have had a greater effect on the brain and thus the fusion and combination responses have been created.