Do Bilingual Infants Have Better Memory?
What infant memory studies tell us about the bilingual advantage
Posted November 18, 2015
Post written by Aneta Pavlenko.
Like any other area of research, the study of bilingualism is a difficult enterprise, and one of the greatest pleasures of academic life is to read papers whose authors are unafraid to acknowledge the contradictions in their own findings and to raise questions, instead of providing answers. A recent paper by Natalie Brito (Columbia University), Núria Sebastián-Gallés (Universitat Pompeu Fabra) and Rachel Barr (Georgetown University) manages to do just that in addressing a central question in bilingualism research, the effects of learning two or more languages on our cognitive abilities (see here).
Does bilingualism make us more attentive, more flexible, more immune to cognitive problems later in life? If so, how could bilingual experience produce such an advantage? One theory links the bilingual advantage to early childhood and the need to discriminate between the sounds of two languages and to detect two sets of patterns, instead of one, within the stream of speech (on how bilingual infants go about this, see here). This experience may make bilingual babies better language learners, more attentive to language structures and more flexible in assigning meanings to words but does it also make them smarter? Do they, for instance, develop better memory?
From their very first months, infants display an uncanny ability to distinguish familiar sights (dada! bottle!) and sounds (mama’s language!). At the same time, they cannot tell us what they are thinking and their memories are much more fragile than those of older children who can take advantage of linguistic encoding. The inability to rely on words makes the study of infant memory a challenging enterprise that requires creativity and unlimited patience with fussy participants who fidget because they are tired, cranky or hungry or simply fall asleep. They are also easily distracted – even the slightest changes in stimuli or context can disrupt their memory performance. Yet the ability to retrieve memories despite the changes in context or visual cues – called memory flexibility – is critical for our survival and learning because it allows us to generalize and to link previous experiences to novel situations and it improves dramatically with age.
To study memory flexibility at its inception, Brito and her colleagues used a task, known as the deferred imitation memory generalization task, where the infant sits on the mother’s lap, while the experimenter shows a series of actions with a puppet (e.g. a yellow duck) wearing a mitten with a large jingle bell hidden inside: pull off mitten, shake mitten to ring the bell, replace the mitten. Then the experimenter and the infant may play a game, such as Hide the pots, and afterwards the infant is presented with a new puppet (e.g., a black and white cow) and encouraged to interact with it. Findings show that at the age of 18 months monolingual infants can reproduce the previously witnessed actions after a time delay but only if the puppet is the same. If the duck is replaced with a black and white cow, the cow is treated as a new object and the actions are not generalized.
But what if the children are exposed to two languages from birth? Could systematic practice of relying on different retrieval cues (different sounds, different words, different people speaking respective languages) enhance their memory flexibility and ability to generalize across instances? To answer this question, the researchers used the same task to compare the behavior of 42 monolingual and 30 bilingual 18-month olds. Monolingual infants were exposed to English (in Washington, DC) and either Catalan or Spanish (in Barcelona). Fifteen of the bilingual infants were exposed to English and Spanish (in Washington, DC) and the other fifteen to Catalan and Spanish (in Barcelona). The results revealed that the bilingual infants outperformed the monolingual ones on deferred imitation, displaying greater memory flexibility and an earlier ability to generalize across different contexts (e.g., from the yellow duck to the black and white cow). The similarity between the languages (greater in the case of Catalan and Spanish) did not appear to influence the results.
These findings appear to support the bilingual advantage idea but here comes an interesting twist. In the follow-up study, the researchers tested fifteen trilingual infants of the same age and found no differences between monolingual and trilingual infants on memory flexibility and no generalization advantage for infants exposed to three languages from birth. This unexpected finding challenges any theory that makes a simple connection between cognitive advantage and bi/multilingualism and raises new questions, some of which can only be addressed through longitudinal research.
Is there a positive message to be gained from this research for parents and grandparents? There certainly is. While at the end of the day, bilingual and multilingual babies may or may not be better than their monolingual peers on tasks unrelated to language, they are certainly not worse – they are developing normally and the cognitive resources necessary for differentiating between two or more languages are not recruited at the expense of other areas of cognitive development.
For a full list of "Life as a bilingual" blog posts by content area, see here.
Photo of a kid and his mom playing with toy animals from Shutterstock.
Brito, N., Sebastian-Galles, N., & R. Barr (2015) Differences in language exposure and its effects on memory flexibility in monolingual, bilingual, and trilingual infants. Bilingualism: Language and Cognition, 18 (4), 670-682.
Aneta Pavlenko's website.