Lecture 15: Bilingualism

Question 1

Damage to Broca’s Area does not
ALWAYS result in Broca’s aphasia

Answer 1

Dronkers et al. (1996) reported 22 patients with
damage to Broca’s area identified by imaging –
but only 10 had Broca’s aphasia. Damage to
underlying white matter, subcortical structures

High-resolution MRI revealed that lesions in both cases
extended into more medial brain regions than Broca
could have observed

Question 2

Broca’s aphasia: Comprehension
problems

Answer 2

-agrammatism: deficits in processing
grammatical aspects of lanaguage.

-“The boy ate the cookie” understood (little demand for access to grammatical rules; never
think “the cookie ate the boy”)

-“The boy was hit by the girl” might be
misunderstood (grammatical rules needed to
disambiguate who hit whom)

Not just production problems, also comprehension.

Question 3

agrammatism

Answer 3

deficits in processing
grammatical aspects of lanaguage

Question 4

Broca’s area shows increased activity
during processing of grammatically
complex sentences

Answer 4

The child enjoyed the juice that stained the rug”
(simple)
“The juice that the child enjoyed stained the rug
(complex)

Broca’s area shows increased activity
during processing of grammatically
complex sentences

Association of Broca’s area solely with
motor word images in classical model is too
simplistic

Question 5

Wernicke’s Area

Answer 5

Carl Wernicke
reported on
patients who:
-had fluent speech
-but nonsensical sounds
-or nonsense sentences

Wernicke’s area
near auditory cortex

-Wernicke thought that this area is involved with
auditory
storage of words, which he believed would result in problems with word comprehension and producing meaningful
sentences (can’t choose right words, can’t monitor verbal output)

Question 6

Wernicke’s Aphasia: Fluent Aphasia

Answer 6

Question 7

Not a Perfect Association between
Wernicke’s Aphasia and Damage to
Wernicke’s Area

Answer 7

In one study involving 70 patients with Wernicke’s aphasia, 7 had brain damage
confined to regions outside Wernicke’s area

Other studies indicate that Wernicke’s aphasia occurs only following damage to
Wernicke’s area and surrounding posterior temporal lobe regions, or damage to
white matter paths that connect these regions to other parts of the brain

Wernicke’s Aphasics have Output
Problems as well as Comprehension
Problems

Sometimes have naming problems

Question 8

Classical View of wernicke’s aphasia and how it has changed

Answer 8

Wernicke’s aphasia reflects loss of linguistic
knowledge, which impairs comprehension

• Evidence against the classical view: Wernicke’s aphasics show intact
  semantic priming on a lexical decision task despite problems with
  explicitly comprehending the semantic relationship between words,
  e.g., “doctor” primes lexical decision to “nurse” even though
  patients fail to comprehend relationship between the two when
  explicit judgment is required.
• Perhaps reflects a problem with processes that normally provide
  access to linguistic information for explicit, goal-directed use in real-
  time.
• Evidence favors the idea that patients cannot integrate words into
  the context of a sentence quickly enough to allow normal
  comprehension

Question 9

Are Broca’s and Wernicke’s areas
involved only in heard/spoken languages,
or do they serve a more general
linguistic function

Answer 9

Evidence from American Sign Language (ASL)
3 groups were scanned with fMRI while processing
sentences either in written English or ASL:

1) Normally hearing, monolingual,native speakers of English
who did not know any ASL.

2) Congenitally deaf individuals whose native language was
ASL and learned English late/imperfectly

3) Normally hearing “native signers” who were born to
deaf parents and learned both ASL and English
as their native language

Cortical areas displaying activation for English sentences (vs.
nonwords) for each subject group.
Neville et al.
Broca’s and
Wernicke’s
areas active for
hearing group and to
some extent native
signers, but not
for deaf

Broca’s and
Wernicke’s
areas active
for deaf and
native signers, but
not for hearing

Question 10

Broca’s and Wernicke’s areas

Answer 10

We can think of Broca’s and Wernicke’s areas as two nodes in a larger left
hemisphere language processing network that is critical for both comprehension
and production. Damage to the entire network produces global aphasia – problems
with both comprehension and production.

Question 11

global aphasia

Answer 11

Damage to the entire language processing network network produces global aphasia – problems
with both comprehension and production.

Question 12

There are Costs Associated with Bilingualism

Answer 12

• Generally reduced vocabulary in each language compared with
  monolinguals
• Slower to name pictures and commit more errors than
  monolinguals
• More prone to tip-of-the-tongue states

Question 13

Early negative views of bilingualism

Answer 13

(1) Children who are instructed bilingually from an early
age will suffer cognitive or intellectual retardation in comparison with their monolingually instructed
counterparts.
(2) They will not achieve the same level of content master
as their monolingually instructed counterparts.
(3) They will not achieve acceptable native language or
target language skills.
(4) The majority will become “anomic” individuals without
affiliation to either ethnolinguistic group

The early negative views have been challenged and largely
replaced by a much more positive picture emerging from research in
cognitive psychology and cognitive neuroscience

Question 14

Cognitive Neuroscience of Bilingualism
Two general issues

Answer 14

1. Nature of bilingual brain function: What brain mechanisms
   control language use?
2. Effects of bilingualism on the brain What effect does
   bilingualism have on brain function and cognition?

Question 15

Language Use in Bilinguals

Answer 15

• Both languages of bilinguals are active when using one of them:
  semantic priming of lexical decision occurs equally when prime and target are in same language (e.g., body-hand <ready-hand) and when they are in different languages (e.g., cuerpo-hand<listo-hand).
• Transfer of semantic priming across languages implies common
  underlying conceptual/semantic representation.
• Neuroimaging studies indicate that overlapping regions, including Broca’s and Wernicke’s area, are recruited by L1 and L2 (esp. in early bilinguals; e.g., Kim et al. 1997, Nature).

Question 16

How does bilingual brain distinguish and control
which language is in use?

Answer 16

Since both languages are activated during language use, and
overlapping regions are recruited by L1 and L2, a fundamental problem for the bilingual brain is to distinguish and control which language is in
use.

Crinion et al. (2006, Science) developed a novel approach, using a semantic priming paradigm.

Logic: identify brain regions whose response to semantic priming (i.e.,
reduced activity or adaptation) is language dependent. Such regions
should be able to distinguish which language is in use.

Key finding: In bilinguals, the left caudate uniquely showed a language-
dependent semantic priming effect

Question 17

Semantic priming task: Subjects instructed to make a
yes/no semantic decision about the second word in
response to a question about its meaning

Answer 17

1) Prime and target in same language with unrelated meanings (e.g.
ladle–SHOWER; bathtub–SPOON)

2) Prime and target in same language with semantically related
meanings (e.g. bathtub– SHOWER; ladle–SPOON)

3) Prime and target in different languages with unrelated meanings
(e.g. suppenkelle– SHOWER; badewanne–SPOON)

4) Prime and target in different languages with semantically related
meanings (e.g. badewanne–SHOWER; suppenkelle–SPOON)

Used both German-English and Japanese-English bilinguals.
Behavioral semantic priming occurred regardless of whether prime and
target are in the same language or different languages

Question 18

Left caudate involvement in bilingual language
processing: Neuropsychological evidence

Answer 18

Abutalebi et al. (2000, Neurocase) studied a trilingual (Armenian-English-
Italian) woman who suffered a stroke in the left caudate.

Preserved comprehension in all three languages; picture naming above 80% accuracy in all languages.

Main problem was loss of control over which language she
was using: during language production, she spontaneously and involuntarily
switched among her three languages.
Supports the idea that left caudate plays a role in controlling/selecting
specific language.

Caudate is part of basal ganglia; plays a role in controlling and selecting
motor sequences.

Question 19

What brain mechanisms
control language use

Answer 19

Neuroimaging evidence indicates that left caudate as well as other prefrontal
cognitive control regions are important for controlling which language is in use

Question 20

What effect does
bilingualism have on brain function and cognition?

Answer 20

• Both languages of bilinguals are active when using one of them, even in
  strongly monolingual contexts
• Therefore, lexical access involves competition between languages, which
  requires a mechanism to select appropriately.
• Early data showed that monolingual and bilingual children were equally capable of detecting grammatical violations in meaningful sentences (e.g., ‘Apples growed on trees’).
• BUT: When the sentences were semantically anomalous, (e.g., ‘Apples growed on nose’), bilingual children were more accurate in detecting
  grammatical violations (Bialystock, 1988, Developmental Psychology).
  Why?
• Performance requires the ability to ignore the misleading meaning and
  focus only on the grammar – selection.

Question 21

Conflict and Executive Control (EC; aka
Cognitive Control)

Answer 21

• Constant use of EC for language selection  massive
  practice
• If so, then there should be situations in which
  bilinguals show enhanced EC
• EC consists of domain-general processes, so effects
  should be found broadly

Question 22

Stroop Effect

Answer 22

Slower to Name Color When Color and Word Don’t
Match (Incongruent) than when Color and Word Match (Congruent)

Question 23

Stroop Effect
Incongruent – Congruent

Answer 23

Smaller Stroop effect for bilinguals
Bilinguals also show enhanced performance compared with monolinguals on several other
tasks that require executive/cognitive control – effects observed for children as well as young
& old adults.

Question 24

How Broad is the Impact of Bilingualism?

Answer 24

Some studies with older adults suggest that bilingualism may
protect against normal cognitive decline, perhaps because
bilinguals rely less on prefrontal control regions that are
especially affected by aging (BAPSS)

Question 25

Onset of Alzheimer’s Dementia

Answer 25

* “Cognitive reserve” (e.g., higher educational levels, stimulating activities) can protect against onset of decline related to dementia (see Stern, Neuropsychologia, 2009) * Does bilingualism constitute a source of cognitive or brain reserve? * Clinic records: diagnosis, background, language history, cognitive details, Mini-Mental State Exam (MMSE; brief 11 item screening test that provides simple measures of orientation, calculation, recall, etc.; scores range 1-30, <25=impaired) * Asked about age at which patient received diagnosis of dementia (Alzheimer’s)

Question 26

Effects of bilingualism on the brain:

Answer 26

Evidence that lifelong bilingualism can enhance cognitive control (Stroop effects) in some studies – but effects are narrower than once thought, not reliable in young adults. Imaging studies provide evidence for “BAPSS” pattern. Bilingualism may delay the onset of AD. Factors such as immigration status do not seem to be critical; bilingualism may constitute a source of cognitive reserve that protects against age- related cognitive decline and masks the effects of AD pathology.

Question 27

Is bilingualism protective against onset of AD?

Answer 27

Bialystok et al. (Neuropsychology, 2014) tried to address confounding factors: *They found that bilinguals were more likely to be immigrants than monolinguals, but there was no correlation between immigration status and age when medical attention sought. *Battery of cognitive tests given to monolinguals and bilinguals on first visit to clinic. *Replicated finding that bilinguals were older, but their performance on the cognitive battery was similar to monolinguals, suggesting that they weren’t waiting longer (i.e., waiting until they had more severe cognitive problems) to seek medical attention

Question 28

Classical View: Wernicke’s aphasia reflects loss of linguistic knowledge, which impairs comprehension * Evidence against the classical view:

Answer 28

wernicke’s aphasics show intact semantic priming on a lexical decision task despite problems with explicitly comprehending the semantic relationship between words, e.g., “doctor” primes lexical decision to “nurse” even though patients fail to comprehend relationship between the two when explicit judgment is required. * Perhaps reflects a problem with processes that normally provide access to linguistic information for explicit, goal-directed use in real- time. * Evidence favors the idea that patients cannot integrate words into the context of a sentence quickly enough to allow normal comprehension

Question 29

Bilingualism: * Both languages of bilinguals are active when using one of them * Evidence from semantic priming

Answer 29

Reaction times for making a decision about a word speeds up when 2 words are in the same language (e.g., body-hand) AND when they are in different languages (e.g., cuerpo-hand) * This transfer of semantic priming across languages implies that you access a common underlying conceptual/semantic representation of words in BOTH languages * However, there is no perceptual priming across languages Studying “horse” primes the exact word “horse” on a word-stem completion task, but doesn’t prime “caballo” * Thus, there is a separation between conceptual knowledge of a word and its physical form

Question 30

Advantages of Bilingualism

Answer 30

* Early views of bilingualism were very negative, but now, bilingualism may have a positive effect, especially on

Question 31

Selection processes (i.e., selecting what is relevant, ignoring the rest)

Answer 31

Given that both languages are active, there is constant, inherent competition between the 2 languages * Bilinguals require a mechanism that allows them to constantly select the appropriate language and practice effect on selection Bilinguals are more accurate at detecting abnormal grammatical violations, a task that requires them to ignore the misleading meaning of the sentence abnormality and focus only on the grammar * Example: “Apples grow on nose.”

Question 32

Advantages of Bilingualism

Answer 32

* Executive Control * Selection processes Debate over bilingualism conferring advantages in executive function * Bilingualism can also confer advantages in the context of Alzheimer’s and dementia

Question 33

* Executive Control

Answer 33

Language selection requires constant use of executive control, so bilinguals get a lot of practice * Bilinguals show reduced Stroop effect (task that taps into executive control)

Question 34

Bilingualism and Stroop Effect

Answer 34

* Stroop effect: People are generally slower to name a color when the color and word don’t match (incongruent) than when the color and word do match (congruent) * Requires overriding what the word says to name the color (taps into executive control) Bialystok & Craik (2010): Bilinguals show reduced stroop effect (i.e., are not slowed down as much) compared to monolinguals

Question 35

* Bilingualism can also confer advantages in the context of Alzheimer’s and dementia

Answer 35

* Bilingualism can also confer advantages in the context of Alzheimer’s and dementia * Mechelli et al., 2004: Bilinguals show increased grey matter density in left parietal region (active during word fluency/generation tasks), and activity in this region is positively correlated with proficiency- protective factor in brain tissue atrophy? Bialystok et al, 2007: Bilinguals have a later onset of Alzheimer’s despite less education than monolinguals à may constitute a source of “cognitive reserve” (i.e., higher education levels and engagement in other simulating activities) that can protect against onset of dementia-related decline

Question 36

Impact of Bilingualism on the Brain

Answer 36

Grundy et al., 2017: Neuroimaging of bilingualism * When first learning a new language, bilinguals rely on prefrontal resources to help resolve competition between languages (i.e., deciding which language to choose) * Over time, there are increases in grey matter in multiple brain regions, as well increases in white matter that connect anterior regions (involved in cognitive control) and subcortical/posterior regions (for motor and perceptual processing) * Eventually, bilinguals rely less on anterior regions and more on subcortical/posterior regions – “BAPSS” (Bilingual Anterior Posterior Subcortical Shift) à shift from top-down processing requiring cognitive control, to more automatic processing

Question 37

Costs of Bilingualism

Answer 37

Reduced vocabulary in each language * Slower to name pictures and commit more errors * More prone to tip-of-the-tongue states

Question 38

advantages of bilingualism

Answer 38

Bilinguals have more refined selection processes and executive control (side effect of having to select which language to use all the time) * Have higher grey matter density in left parietal region and increased white matter connections between anterior and subcortical/posterior regions * Bilingualism is a protective factor in Alzheimer’s and dementia (increased grey matter density, later onset)

Question 39

disadvantages of bilingualism

Answer 39

Reduced vocabulary in each language * Slower to name pictures and commit more errors * More prone to tip-of-the-tongue states

Question 40

* How does the bilingual brain distinguish and control which language is in use?

Answer 40

* Crinion et al. (2006) used a semantic priming paradigm: * Task: Presented with pairs of words, ignore the first word, and make a decision about the second word based on its meaning (e.g., ladle – SPOON)

Question 41

Semantic priming:

Answer 41

Faster to make a judgment about a word if the preceding word is semantically/conceptually related Brain regions sensitive to semantic priming of a words should show reduced activation when words are semantically related Brain regions sensitive to semantic priming that is LANGUAGE DEPENDENT should be able to distinguish which language is in use (i.e., reduced activity for words in the same language but not if words are in different languages)

Question 42

How does the bilingual brain distinguish and control which language is in use? * Crinion et al. (2006) used a semantic priming paradigm:

Answer 42

Task: Presented with pairs of words, ignore the first word, and make a decision about the second word based on its meaning (e.g., ladle – SPOON) Crinion et al. (2006), continued: * 4 conditions: * 1) Prime and target are in same language with unrelated meanings (e.g., ladle – SHOWER, bathtub – SPOON) * 2) Prime and target are in same language with related meanings (e.g., ladle – SPOON, bathtub – SHOWER) * 3) Prime and target are in DIFFERENT languages with unrelated meanings (e.g., suppenkelle – SHOWER, badewanne – SPOON) * 4) Prime and target are in DIFFERENT languages with related meanings (e.g., badewane – SHOWER, suppenkelle – SPOON) A brain area that cares about which language is being used would only show semantic priming to condition 2

Question 43

Controlling Language Use * Crinion et al. (2006), continued: Left anterior temporal lobe/pole:

Answer 43

Involved in general semantic processing, shows semantic priming but doesn’t care about whether words are in the same or different languages (priming effect for both conditions 2 and 4)

Question 44

Controlling Language Use * Crinion et al. (2006), continued: Left caudate

Answer 44

(part of basal ganglia that controls/selects motor sequences): Shows semantic priming effect only for pairs of words in the SAME language (priming effect for condition 2 only) is important for selecting and controlling the language in use

Question 45

Damage to left caudate results in

Answer 45

Abutalebi et al., 2006: Damage to left caudate results in loss of control over which language is in use (involuntarily and spontaneously switched among Armenian, English, and Italian) * Left caudate seems to be specifically linked to linguistic control across a number of different studies * Unclear whether restricted lesions to left caudate would also impact other tasks requiring cognitive control (e.g., Wisconsin Card Sorting)

Question 46

* When bilinguals use one language, what happens to the other one?

Question 47

* What are the disadvantages of bilingualism?

Question 47

* What are the advantages of bilingualism?

Question 48

* How does the bilingual brain distinguish and control which language is in use?