Legend: Results of a study in which toddlers learned new words in environments with different levels of background noise. The solid vertical line marks the onset of the target word. The dashed vertical line marks the beginning of the test window (300 ms after the onset of the spoken word). Chance performance is .5. Toddlers were more likely to look at the correct object after hearing its label when they learned it in a quieter environment (blue line; 10 dB difference between the target word and background noise) than when they learned it in a noisier environment (red line; 5 dB difference between the target word and background noise). These results suggest that toddlers are better at learning words in quieter environments.
Citation: McMillan, B., & Saffran, J. R. (in press). Learning in complex environments: The effects of background speech on early word learning. Child Development.
Abstract: While most studies of language learning take place in quiet lab settings, everyday language learning occurs under noisy conditions. The current research investigated the effects of background speech on word learning. Both younger (22- to 24-month-olds; n=40) and older (28- to 30-month-olds; n=40) toddlers successfully learned novel label-object pairings when target speech was 10 dB louder than background speech, but not when the signal-to-noise ratio (SNR) was 5 dB. Toddlers (28- to 30-month-olds; n=26) successfully learned novel words with a 5 dB SNR when they initially heard the labels embedded in fluent speech without background noise, before they were mapped to objects. The results point to both challenges and protective factors that may impact language learning in complex auditory environments.
About the Saffran Lab: The Saffran lab studies how infants learn about the auditory world, particularly the beginnings of language acquisition and music perception.One line of research presently being pursued in the Saffran lab concerns the problem of word segmentation. As adult listeners, we perceive word boundaries when listening to a familiar language. However, these boundaries disappear when we hear a foreign language. This is because speakers do not consistently pause between words.