Two Times Four = Dos Por Cuatro: Simple Arithmetic Processing in the Bilingual Brain
Typically, bilinguals learn multiplication facts in only one instruction language (LA+), leaving them at a disadvantage when performing multiplication in their other language (LA-). This behavioral disadvantage for LA- is consistently reported in the literature, sparking a debate over how bilinguals access these facts from memory across languages. Math cognition models, based on evidence from adults, suggest that the underlying neurocognitive processes used when bilinguals perform multiplication are different or less efficient in their LA-. However, no studies to date have determined the cognitive processes engaged for arithmetic across languages in bilingual children. In Experiment 1, event-related potentials (ERPs) were used a measure of real time brain activity to show that bilingual children elicit similar brain responses across languages. This finding was surprising given that the literature reports robust language differences. However, it is possible that these results reflect the balanced language abilities of our child sample, since many previous bilingual arithmetic studies tested adults with a range of language abilities. Indeed, findings from Experiment 2 suggest that balanced bilingual adults who learned both languages early in life also show no difference in the brain response to verifying multiplication facts across languages. However, Experiment 3 suggests that fluent bilingual adults can show subtle differences across languages when processing more difficult multiplication facts in comparison to easier, more practiced facts. Together, this suggests that the bilingual brain is dynamic and flexible when processing arithmetic, in contrast to the strict belief that early arithmetic learning was the sole driver of language differences.