While some evidence has suggested that bilinguals have developed enhanced inhibitory control abilities -- the ability to suppress or tune out stimuli that are irrelevant to the task at hand -- other evidence suggested that bilinguals possess enhanced attentional control abilities and are better able to concentrate on a specific stimulus.
"Our findings suggest that the way that data has been analysed might not have only led to the wrong conclusion that bilinguals have superior inhibition abilities, it might have also contributed to these replication failures," said Andrea Krott, researcher at the University of Birmingham in the study, published in the journal Bilingualism: Language and Cognition.
The study recruited 99 participants to complete three well known psychological tests that measure inhibitory control ability -- the Simon task, the Spatial Stroop task and the Flanker task.
Among them, 48 were highly proficient English-Chinese bilingual, who had learned English before the age of 10 and could switch between languages on a daily basis, and 51 were English monolingual speakers.
The important measure was the time it took participants to respond to the stimuli presented in the tests on a computer screen.
The novelty of the study was to examine slow response times separately from the more usual fast responses. This showed that the two participant groups were similarly good at inhibiting interfering stimulus features in the bulk of their responses. However, bilinguals did not have as many very slow responses as monolinguals.
These results suggest that bilingual speakers have better sustained attention than monolingual speakers, but not better inhibition abilities.
"Our research suggested that the lifetime task of switching between languages appears to enhance the ability to maintain attention," Krott added.
