We examined the effect of linguistic comprehension on early perceptual encoding in a series of electrophysiological and behavioral studies on humans. Using the fact that pictures of faces elicit a robust and reliable evoked response that peaks at ~170 ms after stimulus onset (N170), we measured the N170 to faces that were preceded by primes that referred to either faces or scenes. When the primes were auditory sentences, the magnitude of the N170 was larger when the face stimuli were preceded by sentences describing faces compared to sentences describing scenes. In contrast, when the primes were visual, the N170 was smaller after visual primes of faces compared to visual primes of scenes. Similar opposing effects of linguistic and visual primes were also observed in a reaction time experiment in which participants judged the gender of faces. These results provide novel evidence of the influence of language on early perceptual processes and suggest a surprising mechanistic description of this interaction: linguistic primes produce content-specific interference on subsequent visual processing. This interference may be a consequence of the natural statistics of language and vision given that linguistic content is generally uncorrelated with the contents of perception.
Monday, January 03, 2011
Influence of language on perception
Landau et al. show that hearing recorded sentences describing faces (versus places) enhances a subsequent electrophysiological marker of brain responses to pictures of faces, while seeing pictures of faces diminishes the subsequent responses. This shows that language influences early stages of visual processing.