Why Bilinguals Experience the World Differently

Why Bilinguals Experience the World Differently

Viorica Marian Ph.D.

The reality is that sensory perception can be nudged, distorted, and radically transformed by anything from the languages we speak to the surrounding visual context–something that is dramatically illustrated by the strength of perceptual illusions. Like a virus, a well-designed illusion contains just the right combination of features to essentially hijack the “machinery” of the perceptual system, including learned heuristics and innate functions, and make it do what it always does – interpret sensory input based on (usually) reliable cues. Unlike a virus, perceptual illusions are generally harmless, and can even provide a glimpse into the inner workings of our minds. They can also shed light on how our personal experiences, such as experiences with different languages, shape how we perceive the world around us.

To illustrate, consider the audiovisual illusion called the McGurk Effect: When we hear a speech sound, such as “ba,” but see an incongruent lip movement, such as “ga,” the brain tries to reconcile this discrepancy, often resulting in the perception of a completely different sound, such as “da.” Our research shows that bilinguals are more likely to experience the McGurk Effect than monolinguals, suggesting that multilingual experience alters multisensory integration. One potential explanation is that bilinguals may, at least initially, need to rely more on visual information to make sense of complex, multilingual speech. Indeed, there is evidence that babies growing up in multilingual households attend to the mouths of speakers to a greater degree than infants in monolingual households. In a recent paper, we show that early differences in how bilinguals and monolinguals attend to speech-relevant inputs continue to shape how, and even how well, individuals process sensory information throughout their lives. 

Utilizing neuroimaging tools such as EEG and fMRI, researchers have demonstrated that bilingual children and adults show visible differences in the processing of auditory stimuli compared to monolingual peers. These effects have been observed in neural regions devoted to higher-level cognitive functions, such as those responsible for controlling attention, as well as in the evolutionarily ancient auditory brainstem, which can encode sounds so faithfully that it is possible to play back recognizable speech and music using the electrical signals generated by the brain.