The Cognitive Advantages of
Language Abilities
Judith F. Kroll
Department of Psychology
Center for Language Science
Pennsylvania State University
University Park, PA 16802 USA
January 25, 2011
More people in the world are bilingual than monolingual.
But until very recently, most research on language and cognition
examined only monolingual speakers of a single language and
typically speakers of English as the native language.
There are many reasons to learn a second language…
Some of these reasons are more positive than self defense!
 Current research demonstrates that both of a bilingual’s languages are
active regardless of the intention or requirement to use one language alone.
 The parallel activity of the two languages is hypothesized to produce
competition.
 Skilled bilinguals rarely make the error of speaking the wrong language
yet they often code switch with other similar bilinguals in the middle of a
sentence, suggesting that they possess an exquisite mechanism of cognitive
control.
 A life of resolving cross-language competition appears to confer
positive consequences for cognition
The bilingual is a mental juggler: Both languages appear to be
active regardless of the requirement to use one language alone:
Dutch-English speaker
“bike”
“fiets”
Parallel activation in listening, reading, and speaking
What is the consequence of parallel activity and competition across
the bilingual’s two languages? The hypothesis is that mental juggling
creates expertise.
Bilingualism may confer specific cognitive benefits to executive
function and attention to enable bilinguals to:
 ignore irrelevant information
 resolve conflict among competing alternatives
 minimize the costs associated with task switching
To illustrate:
Bilingualism may offer protection against the normal declines in
attentional control associated with aging.
Bialystok et al. (2005): Older bilinguals outperform agematched monolingual counterparts on the Simon Task and on
other non-linguistic measures of inhibitory control.
Bialystok et al. (2007): Bilingualism delays the onset of
Alzheimers-type dementia by four years. Language
experience may provide protection to the brain.
The Simon Task
Congruent Trials
Incongruent Trials
“Press the button on the left for Red and button on the right for Green”
Bialystok et al. (2004):
Magnitude of the Simon Effect by Decade:
How much do individuals suffer the consequences of conflict?
Hypothesis: The bilingual advantage arises from a life of
resolving competition across the two languages.
Does the brain reveal the consequences
of using a second language?
Mechelli et al. (2004):
Learning an L2 increases
the density of grey matter
These benefits can be seen for young bilingual children, who seem
better able to resist the allure of misleading information.
To illustrate: Towers Task (Bialystok & Codd, 1997)
 Each block is one apartment; each apartment has one family
 Count the blocks in each tower
 Which apartment tower has more families living in it?
Bilingual children are better than their
monolingual counterparts at recognizing
that the shorter tower has the larger number.
And even for very young bilingual infants…
Kovacs & Mehler (2009) compared bilingual and monolingual
7 month old infants on a switching task involving speech-like
cues.
Babies in a bilingual environment (crib bilinguals)
were better able to switch their attention in response
to a cue in watching a little puppet show than babies
in a monolingual environment.
How does the mental juggling of two languages
create these advantages for cognition?
The evidence to date is largely correlational. Bilinguals are
advantaged relative to monolinguals on measures of attentional
control and executive function.
But what aspect of language use is responsible for these
benefits to cognition?
Hypothesis: Speaking! When you speak two languages you
must choose between them before you utter a single word. Although
babies do not speak so we might consider the baby bilingual
advantages to suggest that there is more than one factor that benefits
bilinguals.
Methods to investigate language learning and language processing
include behavioral measures, e.g., eye tracking and acoustic
analyses of spoken language, and also neuroscience methods to
examine brain activity.
Research on producing speech in the L2 suggests that even
highly proficient bilinguals must inhibit their stronger L1.
That inhibition may impose a set of cognitive demands to
allow proficient speech in the L2 without intrusions from the L1.
Evidence on brain imaging shows that the areas of the brain
associated with cognitive control are particularly active when
bilinguals use their L2.
Is there any context that makes this easier for someone
learning a second language as an adult?
Language immersion: Learners inhibit their L1 when in the
L2 environment (e.g., Linck, Kroll, & Sunderman, 2009)
On the 125th anniversary of the journal Science, Kennedy and Norman (2005)
identified the biological basis of second language (L2) learning as one of the top
125 questions to be answered in the next 25 years of research:
Second Language Acquisition
Bilingualism
1200
1000
Number of
Papers
800
600
400
200
0
1985-89 1990-94 1995-99 2000-04 2005-09
Time Period
Research articles published on Second Language Acquisition
and Bilingualism since 1985 (Web of Science)
But we need more than language immersion for learners. We
need research immersion to enable national and international
research collaborations and to develop networks for training that
will allow the next generation of researchers to become global
scientists:
Penn State University
University Park, PA
The Netherlands
Spain
Germany
UK
China
Bilingualism takes different forms in different places
The Penn State Center for Language Science Bilingualism Network
Support from NSF PIRE (Partnerships for International Research and Education):
2010-2015: Bilingualism, mind, and brain: An interdisciplinary program in cognitive
psychology, linguistics, and cognitive neuroscience
Thank you!