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Cognitive Control Facilitates Attentional Disengagement during Second Language Comprehension

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Bilinguals learn to resolve conflict between their two languages and that skill has been hypothesized to create long-term adaptive changes in cognitive functioning. Yet, little is known about how bilinguals recruit cognitive control to enable efficient use of one of their languages, especially in the less skilled and more effortful second language (L2). Here we examined how real-time cognitive control engagement influences L2 sentence comprehension (i.e., conflict adaptation). We tested a group of English monolinguals and a group of L2 English speakers using a recently-developed cross-task adaptation paradigm. Stroop sequences were pseudo-randomly interleaved with a visual-world paradigm in which participants were asked to carry out spoken instructions that were either syntactically ambiguous or unambiguous. Consistent with previous research, eye-movement results showed that Stroop-related conflict improved the ability to engage correct-goal interpretations, and disengage incorrect-goal interpretations, during ambiguous instructions. Such cognitive-to-language modulations were similar in both groups, but only in the engagement piece. In the disengagement portion, the modulation emerged earlier in bilinguals than in monolinguals, suggesting group differences in attentional disengagement following cognitive control recruitment. Additionally, incorrect-goal eye-movements were modulated by individual differences in working memory, although differently for each group, suggesting an involvement of both language-specific and domain-general resources.
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brain
sciences
Article
Cognitive Control Facilitates Attentional
Disengagement during Second
Language Comprehension
Christian A. Navarro-Torres 1, * , Dalia L. Garcia 1, Vrinda Chidambaram 2and Judith F. Kroll 1
1
Department of Psychology, University of California, Riverside, 900 University Avenue, Riverside, CA 92521,
USA; dalia.garcia@ucr.edu (D.L.G.); jfkroll@gmail.com (J.F.K.)
2Department of Comparative Literature and Languages, University of California, Riverside, 2401 HMNSS
Building, Riverside, CA 92521, USA; vrinda@ucr.edu
*Correspondence: navarro.torresc@gmail.com
Received: 1 April 2019; Accepted: 25 April 2019; Published: 27 April 2019


Abstract:
Bilinguals learn to resolve conflict between their two languages and that skill has been
hypothesized to create long-term adaptive changes in cognitive functioning. Yet, little is known about
how bilinguals recruit cognitive control to enable ecient use of one of their languages, especially in
the less skilled and more eortful second language (L2). Here we examined how real-time cognitive
control engagement influences L2 sentence comprehension (i.e., conflict adaptation). We tested a group
of English monolinguals and a group of L2 English speakers using a recently-developed cross-task
adaptation paradigm. Stroop sequences were pseudo-randomly interleaved with a visual-world
paradigm in which participants were asked to carry out spoken instructions that were either
syntactically ambiguous or unambiguous. Consistent with previous research, eye-movement results
showed that Stroop-related conflict improved the ability to engage correct-goal interpretations, and
disengage incorrect-goal interpretations, during ambiguous instructions. Such cognitive-to-language
modulations were similar in both groups, but only in the engagement piece. In the disengagement
portion, the modulation emerged earlier in bilinguals than in monolinguals, suggesting group
dierences in attentional disengagement following cognitive control recruitment. Additionally,
incorrect-goal eye-movements were modulated by individual dierences in working memory,
although dierently for each group, suggesting an involvement of both language-specific and
domain-general resources.
Keywords:
bilingualism; second language processing; sentence comprehension; cognitive control;
attention; eye-tracking
1. Introduction
Cognitive control is an essential feature of human cognition that enables appropriate goal-directed
behavior through the regulation of basic thoughts and actions [
1
,
2
]. In recent years, the study of
cognitive control has become central to our understanding of language processing [
3
6
]. For example,
several empirical studies suggest an involvement of conflict resolution processes during lexical
access [
7
9
], sentence production [
10
], and sentence comprehension [
11
14
]. Likewise, a number
of lesion studies have established a link between cortical regions considered to be responsible for
resolving interference and language abilities [
15
18
]. The engagement of such cortical regions has been
observed across syntactic and non-syntactic tasks [
6
,
19
21
], suggesting that at least some of the control
processes involved in language are domain-general in nature.
More recently, there has been an attempt to identify the conditions under which cognitive control
is recruited online to facilitate language processing [
22
27
], with the evidence indicating that linguistic
Brain Sci. 2019,9, 95; doi:10.3390/brainsci9050095 www.mdpi.com/journal/brainsci
Brain Sci. 2019,9, 95 2 of 23
features dier in the demands they make on cognitive resources. Of interest to the present study
are cases involving syntactic ambiguity during sentence comprehension and its relation to cognitive
control. As individuals parse a sentence, meanings are rapidly assigned to words and phrases as the
utterance unfolds in order to generate predictions about sentence-level meaning [
28
,
29
]. However,
early interpretations can sometimes lead to erroneous predictions [
30
], forcing the comprehender to
quickly revise and reinterpret the sentence. For example, in a title taken from a CNET online news
article, “Google’s computer might betters translation tool”, the word “might” can act either as an
auxiliary verb or as a noun. Since the former is more frequent than the latter by a ratio of about 134:1,
people are more likely to initially assign the auxiliary verb interpretation, which is incompatible with
the remainder of the sentence. Eventually “betters translation tool” signals a revision process to treat
“might” as a noun, which can result in momentary unwanted interference stemming from the two
incompatible interpretations. Under these conditions, cognitive control is hypothesized to facilitate the
revision process, as well as the selection of the correct interpretation [31].
Perhaps one of the best sources of evidence for online engagement of cognitive control during the
comprehension of syntactically ambiguous sentences comes from a study by Hsu and Novick [
23
].
Unlike most previous research, which relied on correlational analyses between measures of cognitive
control and language performance, Hsu and Novick used a cross-task adaptation paradigm to test for
a causal relation between the two domains. In this version of the paradigm, a button-press Stroop task
was interleaved with visual-world sequences in which participants carried out spoken instructions
by dragging and dropping objects around a visual scene while their eye-movements were recorded.
Spoken instructions contained sentences that are known to induce momentary ambiguity, such as in
the following example:
(1) Put the frog on the napkin onto the box.
Previous research has shown that in examples such as (1), adult listeners initially parse “on the
napkin” as a destination [
32
,
33
]. However, hearing “onto the box” immediately signals a revision
process in which “on the napkin” is treated as a modifying phrase, and not as a destination. Hsu and
Novick argued that such revision process resulted in the momentary activation of two incompatible
syntactic interpretations. They hypothesized that successful recovery from such interference stems
from the recruitment of the same general-purpose control processes that would facilitate the processing
of conflicting information in non-syntactic domains. If so, then participants’ comprehension of
ambiguous instructions such as (1) should improve after experiencing Stroop-related conflict (i.e.,
when visual-world ambiguous sequences are preceded by incongruent Stroop sequences). In line with
this hypothesis, eye-movement results revealed that incongruent, but not congruent, Stroop sequences
facilitated participants’ ability to recover from ambiguous instructions. This was manifested as an
increase in correct-goal fixations and as a decrease in incorrect-goal fixations.
The results from Hsu and Novick [
23
] illustrate the conditions through which the coordination
of cognitive control becomes a critical resource for overcoming linguistic adversity; during sentence
comprehension, the co-activation of multiple linguistic (e.g., semantic, lexical, phonological, and
syntactic) features can lead to unwanted interference that must be resolved quickly through conflict
resolution procedures in order to accomplish the task at hand. This hypothesis is also supported
by previous research indicating that memory training improves online reading comprehension
of syntactically ambiguous sentences, but only when the training engages conflict resolution
processes
[24,25].
Similar to Hsu and Novick [
23
], a more recent visual-world study by Thothathiri,
Asaro, Hsu, and Novick [
27
] found that Stroop-related conflict facilitated the processing of ambiguous
thematic role assignment during the comprehension of passive sentences. Taken together, these studies
illustrate the dynamics of how language processing and cognitive control interact in the short-term.
However, less is known about whether there are long-term experiences, such as lifelong language
experience, that can influence the manifestation of such short-term eects.
Brain Sci. 2019,9, 95 3 of 23
One way to understand how language experience modulates the short-term dynamics between
language processing and cognitive control is by examining bilinguals, given that actively learning
and using a second language (L2) has long-term consequences for the language system [
34
]. Studies
have shown that when bilinguals are speaking or comprehending, both languages are momentarily
activated in parallel, even when the intention or requirement is to use only one [
35
37
]. One outcome
of cross-language activation is that linguistic features of the language not in use can directly influence
online performance in the other target language, even at high levels of proficiency [
38
,
39
]. For example,
when linguistic (i.e., orthographic and/or semantic) features converge across the two languages,
cross-language activation can result in online facilitation [
40
43
], although when features are in conflict
with one another, such as in the case of homographs (i.e., words that overlap cross-linguistically in
orthography but dier in meaning, e.g., the word pan means bread in Spanish) or partially overlapping
syntactic structures, cross-language activation can produce momentary online interference [4447].
An issue of interest to the present study is how bilinguals manage to regulate and suppress
cross-language interference in order to successfully process ambiguity in one language, especially in
the less skilled and more eortful L2. Prior research suggests that, when processing syntactic ambiguity,
L2 speakers have greater diculties revising misinterpretations [
48
] and exhibit dierent (or greater
variability in) attachment preferences from native (L1) speakers [
49
51
]. Although general dierences
between L1 and L2 processing have been previously explained in terms of processing constraints in
the L2 [
52
], more recent evidence suggests that both languages engage the same neural and cognitive
processes [
53
55
] and that these dierences reflect variability in proficiency [
56
], speed of lexical
access [57], and cognitive control ability [14]. In this sense, L2 processing may be more susceptible to
irrelevant (within-language and cross-language) interference [
58
], given that both languages compete
for cognitive resources. Given these constraints, highly proficient L2 comprehension may provide a
unique window to understand dierent aspects of cognitive control recruitment during the processing
of syntactic ambiguity, perhaps in a way that may not be easily observed in monolinguals.
For the reasons outlined above, mastery of L2 processing seems to largely depend on bilinguals’
ability to regulate language-related conflict [
59
,
60
]. The control mechanisms that mediate such conflict
are hypothesized to be domain-general in nature, a claim that is largely supported by neuroimaging
research [
61
64
]. Such interplay is further hypothesized to create long-term consequences for cognitive
functioning [
65
]. Recently, there has been an interest in understanding how bilingual experience
influences the control processes associated with conflict monitoring and attentional disengagement. For
example, recent studies have shown that bilinguals develop high eciency in disengaging misleading
or irrelevant information after experiencing conflict in both linguistic [
66
,
67
] and non-linguistic
tasks [
68
70
]. Bilinguals are also more likely to perform dierently from monolinguals under
conditions of high conflict that require careful monitoring [
71
73
]. However, this research has focused
on examining the long-range consequences on cognitive functioning, where it is assumed that cognitive
control processes gradually adapt to the demands imposed by the language practices that bilinguals
adopt [
64
]. What is less understood is how cognitive control procedures can be utilized by bilinguals in
real time to support language processing, which may be critical for better understanding the long-term
adaptation associated with becoming bilingual.
Present Study
In the present study, we examine whether cognitive control processes modulate how bilinguals
experience syntactic ambiguity in their L2, compared to native speakers of that language. We adopt
the cross-task adaptation paradigm used in Hsu and Novick [
23
], which utilizes a combination of
a behavioral/cognitive (i.e., Stroop) task and a visual-world paradigm [
28
,
74
], both of which are
pseudo-randomly interleaved within the same experimental block. A key feature of the visual world
paradigm is that it allows us to examine the way in which an unfolding sentence can guide visual
attention, which is eortful in and of itself. We test the hypothesis that conflict experienced in a
non-syntactic task will trigger cognitive control procedures that will facilitate subsequent performance
Brain Sci. 2019,9, 95 4 of 23
in a syntactic task. But we additionally explore the idea that bilinguals may engage in this process in
a dierent manner, as a direct result of having to mediate unique demands that are imposed on the
L2 system.
Similar to the idea of conflict adaptation, bilinguals may be able to disengage attention
more eciently immediately following conflict in ways that are not typically observed in
monolinguals
[68,69,72]
. Such an ability may stem from a complex coordination of multiple executive
functions, which may be dicult to characterize depending on the task. However, the visual world
paradigm is an ideal tool to examine and dissociate engagement from disengagement processes.
For example, the sentence ‘put the frog on the napkin onto the box’ could be accompanied by a
visual display in which either one or two frogs are presented. In the former case, adult listeners’
ability to engage attention in the correct destination object (a box) is typically delayed because they
have a dicult time disengaging their attention from the incorrect destination object (i.e., an empty
napkin) [
32
,
75
]. For monolinguals, the ability to navigate through both sources of information seems to
be equally facilitated by cognitive control [
23
,
27
]. However, for bilinguals, it may be possible to observe
a dissociation between the two processes when conflict resolution resources are readily available. This
may be especially true for bilinguals who speak English as the L2, since, as previously mentioned, L2
sentence processing is likely to be more susceptible to interference [56].
In the present study, we focus on a group of proficient bilinguals, all of whom were born and raised
in non-English-speaking environments but began acquiring English after their L1. These individuals
eventually became immersed in English (i.e., Edinburgh, Scotland) as part of their higher education,
although they maintained L1 dominance. Therefore, we hypothesized that, for these bilinguals, online
comprehension in English would be more eortful relative to monolinguals (likely manifesting greater
fixation costs, especially when parsing ambiguous sentences). However, we further hypothesized that
these added costs would create a greater need for cognitive control recruitment, which might yield
group dierences in the timing and/or magnitude of the recovery from ambiguity.
2. Materials and Methods
2.1. Participants
Participants included a total of 26 English monolinguals and 24 bilinguals who acquired English
as the L2. Monolinguals were fluent in English only, had not enrolled in any second-language courses
during college, and had no more than minimal exposure to an L2 prior to college. Bilinguals were all
born and raised in a non-English speaking country and reported using English as the L2 and another
language as the L1. These languages included Arabic (1), Cantonese (2), Cypriot Greek (1), Dutch (1),
German (3), Greek (1), Italian (7), Mandarin (1), Norwegian (2), Romanian (1), Russian (1), and Spanish
(3). Monolinguals were recruited either at the Pennsylvania State University or at the University of
California, Riverside, and received either course credit or $10/hour. Bilinguals were recruited at the
University of Edinburgh and received an equivalent of $10/hour in pounds. All participants gave
informed consent, and the procedures had the approval of the Institutional Review Board of the
Pennsylvania State University and of University of California, Riverside.
Table 1provides the characteristics of participants for both groups. Participants completed a
category fluency task and the operation span (O-span) task [
76
] to assess verbal abilities and working
memory abilities, respectively. In the category fluency, participants were asked to generate as many
exemplars as possible that belong to a semantic category within a 30-second time limit. Monolinguals
were presented with four out of eight possible categories (counter-balanced across participants), and
bilinguals were presented with four unique categories for the L1 and for the L2 in separate blocks.
In the O-span task, participants attempted to solve math equations while simultaneously memorizing
words in English that would have to be recalled later in the task. They also completed a language
history questionnaire to assess self-rated levels of language proficiency, among other characteristics.
Brain Sci. 2019,9, 95 5 of 23
Table 1. Participant characteristics.
Monolinguals Bilinguals
Valid NM (SD) Valid NM (SD)
Age, years 25 21.40 (2.77) 24 23.96 (3.24) **
L2 age of acquisition N/A N/A 24 6.29 (3.03)
English immersion,
years N/A N/A 22 1.52 (1.52)
Self-rated exposure
L1 25 10.00 (0.00) 22 5.05 (2.30) ††
L2 N/A N/A 24 8.46 (2.45)
Self-rated use
L1 25 10.00 (0.00) 22 5.55 (2.41) ††
L2 N/A N/A 24 8.17 (2.65)
Self-rated proficiency
L1 25 9.66 (0.53) 22 9.87 (0.44) ††
L2 N/A N/A 22 8.67 (0.91)
Verbal Fluency
L1 23 58.22 (8.38) 21 49.86 (10.26)
L2 N/A N/A 24 45.04 (8.61) **
O-span
recall score 26 51.04 (5.06) 23 40.35 (8.41) **
response time (ms) 26 2120.48 (297.94) 24 2155.04 (343.47)
Note: Self-ratings were made on a 10-point scale ranging from 1 (no exposure/use/proficiency) to 10 (high
exposure/use/proficiency). Fluency score was measured as the average number of exemplars produced across
semantic categories. O-span recall score was measured as the number of correctly recalled to-be-remembered
English words out of 60 possible. O-span response time indicates the amount of time it took to correctly solve an
equation. Some data were excluded due to experimental or equipment error. ** =significant dierences between
monolinguals and bilinguals at p<0.01 level;
=marginally significant dierence between bilinguals’ L1 and L2;
†† =significant dierences between bilinguals’ L1 and L2 at p<0.01 level.
Bilinguals were slightly older than the monolinguals (t(47) =
2.98, p=0.005), although both
groups consisted of university students. Bilinguals reported acquiring English around age 6 and also
reported becoming immersed in an English environment in recent years as part of their education at
the University of Edinburgh. Self-rated L1 exposure (t(21) =
4.99, p<0.001) and L1 use (t(21) =
3.83,
p=0.001) were relatively low compared to the L2, suggesting restricted access to the L1 likely due to
L2 immersion. Despite this, bilinguals self-rated themselves as being more dominant in their L1 (t
(21) =5.60, p<0.001), and displayed marginally higher verbal fluency in their L1 than in their L2 (t
(20) =1.86, p=0.077). Compared to monolinguals, bilinguals had lower English fluency (t(45) =5.31, p
<0.001), and lower working memory ability (t(47) =5.46, p<0.001), although both groups’ scores fell
within typical ranges. Both groups, however, had similar basic processing speed abilities, as indexed by
the response times for solving math equations in the O-span (t(48) =
0.381, p=0.705). The dierences
in working memory recall, however, are expected considering that working memory has been shown
to dier in the L1 vs. the L2 [77].
2.2. Materials
The materials used for the cross-task adaptation paradigm in our study were taken from Hsu
and Novick [
23
]. No modifications were made to the materials. In this version of the paradigm,
a Stroop task is interleaved with a sentence comprehension task that involves syntactic ambiguity.
During the sentence comprehension portion, participants listened to spoken instructions in English
while viewing a series of objects on the screen, some of which were mentioned in the instructions.
The goal of the participants was to carry out the spoken instructions by clicking and dragging objects
around the screen accordingly. Critical trials involved instructions whose meaning was ambiguous or
Brain Sci. 2019,9, 95 6 of 23
unambiguous. Each critical trial was preceded by Stroop sequences in which the ink color was either
congruent or incongruent.
In the Stroop portion, participants used a three-button mouse to indicate the ink color of the
word as quickly as possible. The response set consisted of blue, green, and yellow. Participants were
randomly assigned to four versions that contained dierent button-color mappings. There was a total
of 120 Stroop sequences, half of which were congruent. For the 60 incongruent sequences, color names
never matched the colors used in the response set (i.e., blue, green, and yellow were never used as
color names).
In the sentence comprehension portion, the instructions were prerecorded by a female speaker,
which contained single sentences such as “put the frog on the napkin onto the box” (ambiguous) or
“put the frog that’s on the napkin onto the box” (unambiguous). In these two examples (see Figure 1),
the visual scene contained a frog on a napkin (target), an empty napkin (incorrect goal), a box (correct
goal), and a horse (competitor). This setup created a context that favored a goal analysis (i.e., treating
“on the napkin” as the correct goal) instead of a modifier analysis (i.e., treating “on the napkin” as
a modifying clause of “frog”). The omission of the complementizer “that’s” would therefore create
momentary ambiguity. In this scenario, hearing “onto the box” would force the comprehender to
revise the initial interpretation of the sentence.
Brain Sci. 2019, 9, x FOR PEER REVIEW 7 of 24
Figure 1. Illustration of the experimental design depicting a Stroop-to-sentence sequence. Figure
taken from Hsu and Novick [23].
2.3. Procedure
Participants were tested in a sound-attenuated room and were seated in front of a computer
monitor. Stimuli for the main task were presented using Experiment Builder software (Version
2.1.140, SR Research, Kanata, ON, Canada). Eye-movements were recorded with an EyeLink 1000
eye-tracker at the University of Edinburgh and an EyeLink 1000 plus at the Pennsylvania State
University and at the University of California, Riverside (SR Research, Ottawa, Canada; temporal
resolution: 1000 Hz; spatial resolution: 1.5°). Stimuli for the secondary tasks were presented in a
separated computer monitor that was connected to a button box and a digital recorder.
Participants first completed the main interleaved task, followed by category fluency, O-span,
and the language history questionnaire. Before starting the main task, participants were given a
practice block of 144 Stroop trials to familiarize themselves with the color-button mapping that was
assigned to them. Immediately after, they were given four practice trials containing visual world
sequences. In the main task, each trial began with the mouse cursor appearing as a fixation point in
the middle of the screen for 500 ms. For Stroop sequences, the cursor was replaced by a stimulus item,
which remained on the screen for 1000 ms or until the participant clicked on one of the mouse buttons.
For the sentence comprehension sequence, the cursor was replaced by visual objects on the screen,
all of which could be moved as soon as they appeared. After a 300 ms delay, participants began
hearing the commands for that trial. During the Stroop portion, participants were encouraged to
press the mouse button corresponding to the ink color of the word as quickly as possible. During the
sentence comprehension portion, participants were told that there would be a limited time to follow
and carry out the spoken instructions using the mouse to drag objects around the screen, and were
encouraged to do so as accurately as possible.
2.4. Analysis
Accuracy and response time data were collected for Stroop trials. For the sentence
comprehension task, eye-movements were recorded. Following Hsu and Novick [23], each quadrant
of the screen was labeled as an interest area. Proportion of fixations were subsequently obtained by
creating sample reports using the EyeLink Data Viewer Tool (Version 3.1.97; SR Research, Ottawa,
Canada). For the purposes of the paper, we focus on analyzing eye-movements given that our main
Figure 1.
Illustration of the experimental design depicting a Stroop-to-sentence sequence. Figure taken
from Hsu and Novick [23].
There was a total of 24 ambiguous and 24 unambiguous sentences. These sentences were
pseudo-randomly interleaved with Stroop sequences. Half of each sentence type was preceded by
congruent Stroop sequences, and the other half was preceded by incongruent sequences. Therefore,
critical trials were manipulated for sentence type (whether the instruction was ambiguous or
unambiguous) and preceding Stroop trial type (whether the instruction was preceded by a congruent
or incongruent Stroop sequence), meaning that each of these experimental conditions contained 12
trials total. There were 48 additional filler sentences that would minimize the saliency of the critical
manipulation. These filler sentences always contained “put” instructions such as “put the walrus
on/onto/under the desk” or “put the monkeys next to each other”. This was done to ensure that
participants did not automatically treat “on the napkin” as a reduced relative clause, since the locative
prepositional phrases in filler trials would contain the correct goal. Like critical trials, filler sentences
were preceded by Stroop sequences, meaning that participants could not anticipate the type of sentence
based on Stroop trial type. Out of the 120 Stroop sequences, 72 were used to create Stroop-to-Stroop
Brain Sci. 2019,9, 95 7 of 23
sequences (ranging from 2 to 4 consecutive Stroop sequences) to make the alternation between the two
tasks less predictable. Together with the fillers, the interleaved design created several Stroop-to-Stroop
(28%), Stroop-to-Sentence (27%), Sentence-to-Stroop (28%), and Sentence-to-Sentence (17%) pairings.
Some pictures were repeated across conditions, but each item combination (e.g., frog-napkin-box
or mug-blanket-doormat) occurred only once. Goal-depicting objects (e.g., napkin, box) were
counterbalanced such that they could appear in the sentence as either the target (first noun phrase),
incorrect goal (second noun phrase), or correct goal (third noun phrase). Object location was
counterbalanced within and across conditions. Two lists were also created in which sentence ambiguity
was counterbalanced within items (i.e., an object that appeared in the ambiguous condition in one list
would appear in the unambiguous condition on the other list).
2.3. Procedure
Participants were tested in a sound-attenuated room and were seated in front of a computer
monitor. Stimuli for the main task were presented using Experiment Builder software (Version 2.1.140,
SR Research, Kanata, ON, Canada). Eye-movements were recorded with an EyeLink 1000 eye-tracker
at the University of Edinburgh and an EyeLink 1000 plus at the Pennsylvania State University and at
the University of California, Riverside (SR Research, Ottawa, Canada; temporal resolution: 1000 Hz;
spatial resolution:
1.5
). Stimuli for the secondary tasks were presented in a separated computer
monitor that was connected to a button box and a digital recorder.
Participants first completed the main interleaved task, followed by category fluency, O-span, and
the language history questionnaire. Before starting the main task, participants were given a practice
block of 144 Stroop trials to familiarize themselves with the color-button mapping that was assigned to
them. Immediately after, they were given four practice trials containing visual world sequences. In the
main task, each trial began with the mouse cursor appearing as a fixation point in the middle of the
screen for 500 ms. For Stroop sequences, the cursor was replaced by a stimulus item, which remained
on the screen for 1000 ms or until the participant clicked on one of the mouse buttons. For the sentence
comprehension sequence, the cursor was replaced by visual objects on the screen, all of which could
be moved as soon as they appeared. After a 300 ms delay, participants began hearing the commands
for that trial. During the Stroop portion, participants were encouraged to press the mouse button
corresponding to the ink color of the word as quickly as possible. During the sentence comprehension
portion, participants were told that there would be a limited time to follow and carry out the spoken
instructions using the mouse to drag objects around the screen, and were encouraged to do so as
accurately as possible.
2.4. Analysis
Accuracy and response time data were collected for Stroop trials. For the sentence comprehension
task, eye-movements were recorded. Following Hsu and Novick [
23
], each quadrant of the screen was
labeled as an interest area. Proportion of fixations were subsequently obtained by creating sample
reports using the EyeLink Data Viewer Tool (Version 3.1.97; SR Research, Ottawa, Canada). For the
purposes of the paper, we focus on analyzing eye-movements given that our main interest was to
examine how cognitive control aects sentence comprehension in real time. We excluded trials with
more than 33% loss in the eye-tracking data (4.9% of the data set).
We calculated the proportion of fixations to the correct and incorrect goal across seven time points.
This included an action period, the final fixation point, corresponding to the oset of the sentence
when participants were able to complete the mouse movements (e.g., 1: Put the, 2: frog (that’s), 3:
on the, 4: napkin, 5: onto the, 6: box; 7: action period). We followed a procedure similar to Hsu &
Novick [
23
], where correct and incorrect goal fixations were analyzed separately. The analysis consisted
of aggregating fixations across the last four time points (i.e., at the onset of “napkin” all the way through
the action period). Hsu & Novick [
23
] conducted two separate analyses, one including correct and
incorrect action responses, and another only including correct action responses. In the present study,
Brain Sci. 2019,9, 95 8 of 23
all analyses included both correct and incorrect action responses. Fixations were analyzed with mixed
eects models using the lme4 software package [
78
] in the R programming environment [
79
]. The main
analyses included contrast coded fixed eects of sentence type (ambiguous =
0.5, unambiguous =0.5),
preceding Stroop trial type (congruent =
0.5, incongruent =0.5), group (monolinguals =0.5,
bilinguals =
0.5), and their interaction. In a second set of analyses, we added a fixed eect of
experimental half (first =0.5, second =
0.5) to examine the modulation of the eects of interest across
time, an analysis that proved to be critical in Hsu and Novick [
23
]. All models included crossed random
eects for participants and items. We attempted to fit random eects using a maximal procedure [
80
].
However, due to convergence failures and problems with singularity, some random slopes had to be
removed to attain convergence. We report the full results of each analysis, including fixed eects and
random eects estimates, in the Supplementary Materials.
Fixations were transformed using an empirical logit function to account for the bounded nature
of proportions. Significance of the coecients was determined using the Satterthwaite approximation
with the lmerTest package, version 3.0-1 [
81
]. Significant interactions and follow-up comparisons were
examined by refitting the model with a dummy coded categorical factor to examine simple eects at
each level of the categorical factor. Note that refitting the model simply re-estimates the parameters
with a dierent reference point without aecting the goodness of fit or the type-1 error rate. Instead, it
simply provides a dierent interpretation of the coecients while keeping the variance constant [82].
3. Results
3.1. Fixations on the Correct and Incorrect Goal
Table 2shows the mean proportion of fixations on the correct and incorrect goal for each group
across conditions. Figure 2shows estimated eects for the correct-goal analysis across conditions (see
also Figures S1 and S2 in the Supplementary Materials). The full model description for the correct
goal analysis is shown on Table S1. There was a main eect of ambiguity (
β
=0.09, SE =0.02, t=6.05,
p<0.001), indicating that the looks to the correct goal were overall lower for ambiguous sentences
compared to unambiguous sentences (Figure S1). There was also a main eect of group (
β
=0.09,
SE =0.02, t=6.05, p<0.001), suggesting that bilinguals had overall reduced correct goal fixations
relative to monolinguals. There was also a significant interaction between ambiguity and preceding
Stroop trial type (
β
=
0.10, SE =0.03, t=
3.02, p=0.004). Simple eects analyses revealed that correct
goal fixations increased for ambiguous sentences when preceded by incongruent Stroop sequences
relative to congruent Stroop sequences (
β
=0.26, SE =0.09, t=2.94, p=0.004), but no such eect was
observed for unambiguous sentences (
β
=
0.11, SE =0.09, t=
1.32, p=0.190). Additionally, the
ambiguity eect was larger for trials preceded by congruent Stroop sequences (
β
=0.14, SE =0.02,
t=5.86, p<0.001) compared to trials preceded by incongruent Stroop sequences (
β
=0.04, SE =0.02,
t=2.25, p=0.031). Confidence intervals around the estimates also indicated that the ambiguity
eect was dierent across the two preceding Stroop conditions (congruent Stroop: 95% CI [0.09, 0.19];
incongruent Stroop: 95% CI [0.01,0.08]), suggesting that the facilitating eect of Stroop-related conflict
minimized fixation dierences between ambiguous and unambiguous sentences. The main eect of
preceding Stroop trial was not significant, suggesting that Stroop performance impacted fixations
patterns only when following incongruent-to-ambiguous sequences. Group did not interact with any
of the other variables in the model, suggesting that this pattern of results was relatively similar across
the two groups.
Brain Sci. 2019,9, 95 9 of 23
Table 2. Mean proportion of fixations by group, condition, and object.
Monolinguals Bilinguals
Correct Goal Mean SD Mean SD
Congruent-Unambiguous 0.51 0.08 0.46 0.06
Incongruent-Unambiguous 0.48 0.06 0.44 0.07
Congruent-Ambiguous 0.41 0.07 0.36 0.05
Incongruent-Ambiguous 0.47 0.07 0.41 0.07
Incorrect Goal
Congruent-Unambiguous 0.05 0.03 0.07 0.03
Incongruent-Unambiguous 0.07 0.03 0.10 0.04
Congruent-Ambiguous 0.13 0.06 0.17 0.07
Incongruent-Ambiguous 0.10 0.04 0.12 0.06
Brain Sci. 2019, 9, x FOR PEER REVIEW 9 of 24
effect of preceding Stroop trial was not significant, suggesting that Stroop performance impacted
fixations patterns only when following incongruent-to-ambiguous sequences. Group did not interact
with any of the other variables in the model, suggesting that this pattern of results was relatively
similar across the two groups.
Table 2. Mean proportion of fixations by group, condition, and object.
Monolinguals Bilinguals
Correct Goal Mean SD Mean SD
Congruent-Unambiguous 0.51 0.08 0.46 0.06
Incongruent-Unambiguous 0.48 0.06 0.44 0.07
Congruent-Ambiguous 0.41 0.07 0.36 0.05
Incongruent-Ambiguous 0.47 0.07 0.41 0.07
Incorrect Goal
Congruent-Unambiguous 0.05 0.03 0.07 0.03
Incongruent-Unambiguous 0.07 0.03 0.10 0.04
Congruent-Ambiguous 0.13 0.06 0.17 0.07
Incongruent-Ambiguous 0.10 0.04 0.12 0.06
Figure 2. Estimated effects for correct-goal fixations for ambiguous sentences as a function of prior
Stroop trial type. Higher values on the y-axis indicate more looks to the correct goal object (e.g., a box.
Fixations were averaged from the onset of the second noun phrase (e.g., napkin) through the action
period. Error bars indicate standard error of the mean.
Next, we examine incorrect goal performance, which is shown on Figure 3 (see also Figures S3
and S4). The full model description is shown on Table S2. In general, the results were similar to those
observed in the correct goal analysis, although group differences emerged. There was a main effect
of ambiguity (β = 0.13, SE = 0.02, t = 5.61, p < 0.001), indicating that hearing ambiguous instructions
resulted in increased looks to the incorrect goal relative to unambiguous instructions (Figure S3). The
main effect of group was again significant (β = 0.07, SE = 0.02, t = 2.95, p = 0.005), suggesting that,
overall, bilinguals spent more time fixating on the incorrect goal than monolinguals. The interaction
between sentence type and preceding Stroop trial was also significant (β = 0.09, SE = 0.04, t = 2.08, p =
0.046), although a marginally significant three-way interaction between sentence type, preceding
Stroop trial, and group also emerged (β = 0.08, SE = 0.04, t = 1.96, p = 0.050).
Figure 2.
Estimated eects for correct-goal fixations for ambiguous sentences as a function of prior
Stroop trial type. Higher values on the y-axis indicate more looks to the correct goal object (e.g., a box.
Fixations were averaged from the onset of the second noun phrase (e.g., napkin) through the action
period. Error bars indicate standard error of the mean.
Next, we examine incorrect goal performance, which is shown on Figure 3(see also Figures S3
and S4). The full model description is shown on Table S2. In general, the results were similar to those
observed in the correct goal analysis, although group dierences emerged. There was a main eect of
ambiguity (β=0.13, SE =0.02, t=5.61, p<0.001), indicating that hearing ambiguous instructions
resulted in increased looks to the incorrect goal relative to unambiguous instructions (Figure S3).
The main eect of group was again significant (
β
=
0.07, SE =0.02, t=
2.95, p=0.005), suggesting that,
overall, bilinguals spent more time fixating on the incorrect goal than monolinguals. The interaction
between sentence type and preceding Stroop trial was also significant (
β
=0.09, SE =0.04, t=2.08,
p=0.046), although a marginally significant three-way interaction between sentence type, preceding
Stroop trial, and group also emerged (β=0.08, SE =0.04, t=1.96, p=0.050).
Brain Sci. 2019,9, 95 10 of 23
Figure 3.
Estimated eects for incorrect-goal fixations for ambiguous sentences as a function of prior
Stroop trial type. Higher values on the y-axis indicate more looks to the incorrect goal object (e.g., an
empty napkin). Fixations were averaged from the onset of the second noun phrase through the action
period. Error bars indicate standard error of the mean.
Follow-up analyses revealed that the interaction between sentence type and preceding Stroop trial
type was only significant for bilinguals (
β
=0.13, SE =0.05, t=2.75, p=0.008) and not monolinguals
(
β
=0.05, SE =0.05, t=1.02, p=0.312). Like in the correct goal analysis, for bilinguals, the eect of
preceding Stroop trial was only significant for ambiguous sentences (
β
=
0.10, SE =0.04, t=
2.51,
p=0.015), such that incorrect goal fixations decreased when ambiguous instructions were preceded by
incongruent Stroop sequences. No such eect was observed for unambiguous sentences (
β
=0.02,
SE =0.03, t=0.92, p=0.359).
The three-way interaction revealed a second group dierence. For bilinguals, when examining
trials preceded by congruent Stroop sequences, the expected eect of ambiguity was significant (
β
=0.19,
SE =0.04, t=5.08, p<0.001), but the dierence between ambiguous and unambiguous sentences was
reduced for trials preceded by incongruent Stroop sequences (
β
=
0.07, SE =0.03, t=
1.92, p=0.060).
For monolinguals, however, dierences between ambiguous and unambiguous sentences remained
regardless of the preceding Stroop sequence (congruent Stroop:
β
=
0.15, SE =0.04, t=
3.94, p<0.001;
incongruent Stroop:
β
=
0.10, SE =0.03, t=
3.00, p=0.004). Additionally, although the eect of
group was not significant for congruent-unambiguous sequences (
β
=0.06, SE =0.03, t=1.82, p=0.071),
there was a significant group dierence for incongruent-unambiguous sequences (
β
=0.08, SE =0.03,
t=3.08, p=0.003). This pattern of results suggests that, for unambiguous sentences, Stroop-related
conflict may have inadvertently increased bilinguals’ looks to the incorrect goal.
The incorrect-goal results obtained thus far suggest important group dierences in the eect of
recovery from ambiguity following Stroop-related conflict. It is possible that this is due to dierences
in the magnitude of recovery from ambiguity, although group dierences can also arise with respect
to when the recovery process began. To further address this issue, we examined the eect of conflict
adaptation (by subtracting incongruent-to-ambiguous fixations from congruent-to-ambiguous fixations)
in two time windows: an early time window (TW1) that included fixations from the second noun
phrase (e.g., napkin) and the disambiguating region (e.g., onto the), and a later time window (TW2)
that included fixations from the third noun phrase (e.g., box) and the action period (see Figures 4
and 5).
Brain Sci. 2019,9, 95 11 of 23
Brain Sci. 2019, 9, x FOR PEER REVIEW 11 of 24
indicating that the overall magnitude of recovery was weaker at TW1 (M = 0.02) and increased at
TW2 (M = 0.06). A main effect of group indicated that the overall magnitude of recovery was greater
for bilinguals (M = 0.05) than for monolinguals (M = 0.02), although this effect was only marginally
significant (F (1, 48) = 3.42, p = 0.071, η2 = 0.07). The interaction between time window and group was
not significant (F (1, 48) = 0.08, p = 0.776, η2 = 0.00). However, as Figures 4 and 5 suggest, recovery
started earlier for bilinguals than for monolinguals. One sample t-tests revealed that, for bilinguals,
the effect of conflict adaptation was significantly different from zero at both TW1 (t (23) = 2.41, p =
0.024) and TW2 (t (23) = 5.63, p < 0.001), but for monolinguals this effect was significant at TW2 (t
(25) = 4.43, p < 0.001) but not at TW1 (t (25) = 0.431, p = 0.670). Taken together, these results suggest
that the group differences are more likely to reflect differences in the timing of cognitive control
engagement, and not necessarily in the magnitude of the effect.
Figure 4. Mean proportion of fixations on the incorrect goal over time for ambiguous sentences as a
function of preceding Stroop trial type. Higher values on the y-axis indicate more looks to the incorrect
goal. Colored error bars indicate 95% confidence intervals.
Figure 4.
Mean proportion of fixations on the incorrect goal over time for ambiguous sentences as a
function of preceding Stroop trial type. Higher values on the y-axis indicate more looks to the incorrect
goal. Colored error bars indicate 95% confidence intervals.
Brain Sci. 2019, 9, x FOR PEER REVIEW 12 of 24
Figure 5. Effect of conflict adaptation (calculated as the difference between mean proportion of
incongruent-ambiguous fixations and mean proportion of congruent-ambiguous fixations) for the
incorrect goal during an early (TW1) and late (TW2) time window. More negative values on the y-
axis indicate greater difference between incongruent-ambiguous and congruent-ambiguous
sequences and, therefore, greater facilitation from incongruent Stroop sequences. Error bars indicate
standard error of the mean.
3.2. Conflict Adaptation during the First and Second Half of the Experiment
The results reported so far suggest that both bilinguals and monolinguals engaged cognitive
control in a similar manner with respect to correct goal fixations, but differed in terms of how control
was recruited when fixating on the incorrect goal. Which aspects of cognitive control can account for
such discrepancies? One possibility is that reliance on task disengagement procedures maximized
bilinguals’ ability to shift away from incorrect interpretations [54,64]. Another possibility is that
bilinguals relied on conflict monitoring procedures to a greater extent than monolinguals [71–73].
This latter account is particularly interesting, since it would predict for bilinguals general sustained
effects of conflict adaptation throughout the experiment. We attempted to dissociate these two
alternatives by examining how Stroop performance and fixations are modulated by time (here
defined as the first and second half of the experiment).
We first report an analysis of Stroop response time data in the first and second half of the
experiment (Table 3). There was a significant Stroop effect in the first half of the experiment for both
monolinguals (β = 0.03, SE = 0.01, t = 2.08, p = 0.038) and bilinguals (β = 0.04, SE = 0.01, t = 2.71, p =
0.007), indicating that incongruent trials resulted in slower latencies relative to congruent trials.
However, the Stroop effect disappeared in the second half of the experiment for both groups
(monolinguals: β = 0.02, SE = 0.01, t = 1.18, p = 0.236; bilinguals: β = 0.00, SE = 0.02, t = 0.22, p = 0.826).
This is consistent with previous literature showing that Stroop costs dissipate over time due to
practice effects [83].
Figure 5.
Eect of conflict adaptation (calculated as the dierence between mean proportion of
incongruent-ambiguous fixations and mean proportion of congruent-ambiguous fixations) for the
incorrect goal during an early (TW1) and late (TW2) time window. More negative values on the y-axis
indicate greater dierence between incongruent-ambiguous and congruent-ambiguous sequences and,
therefore, greater facilitation from incongruent Stroop sequences. Error bars indicate standard error of
the mean.
Brain Sci. 2019,9, 95 12 of 23
A repeated measures ANOVA (with time window as a within-subjects factor, and group as a
between-subjects factor) revealed a main eect of time window (F(1, 48) =11.26, p=0.002,
η2
=0.19),
indicating that the overall magnitude of recovery was weaker at TW1 (M =
0.02) and increased
at TW2 (M =
0.06). A main eect of group indicated that the overall magnitude of recovery was
greater for bilinguals (M =
0.05) than for monolinguals (M =
0.02), although this eect was only
marginally significant (F(1, 48) =3.42, p=0.071,
η2
=0.07). The interaction between time window
and group was not significant (F(1, 48) =0.08, p=0.776,
η2
=0.00). However, as Figures 4and 5
suggest, recovery started earlier for bilinguals than for monolinguals. One sample t-tests revealed
that, for bilinguals, the eect of conflict adaptation was significantly dierent from zero at both TW1
(t(23) =
2.41, p=0.024) and TW2 (t(23) =
5.63, p<0.001), but for monolinguals this eect was
significant at TW2 (t(25) =
4.43, p<0.001) but not at TW1 (t(25) =
0.431, p=0.670). Taken together,
these results suggest that the group dierences are more likely to reflect dierences in the timing of
cognitive control engagement, and not necessarily in the magnitude of the eect.
3.2. Conflict Adaptation during the First and Second Half of the Experiment
The results reported so far suggest that both bilinguals and monolinguals engaged cognitive
control in a similar manner with respect to correct goal fixations, but diered in terms of how control was
recruited when fixating on the incorrect goal. Which aspects of cognitive control can account for such
discrepancies? One possibility is that reliance on task disengagement procedures maximized bilinguals’
ability to shift away from incorrect interpretations [
54
,
64
]. Another possibility is that bilinguals relied
on conflict monitoring procedures to a greater extent than monolinguals [
71
73
]. This latter account
is particularly interesting, since it would predict for bilinguals general sustained eects of conflict
adaptation throughout the experiment. We attempted to dissociate these two alternatives by examining
how Stroop performance and fixations are modulated by time (here defined as the first and second half
of the experiment).
We first report an analysis of Stroop response time data in the first and second half of the experiment
(Table 3). There was a significant Stroop eect in the first half of the experiment for both monolinguals
(
β
=0.03, SE =0.01, t=2.08, p=0.038) and bilinguals (
β
=0.04, SE =0.01, t=2.71, p=0.007), indicating
that incongruent trials resulted in slower latencies relative to congruent trials. However, the Stroop
eect disappeared in the second half of the experiment for both groups (monolinguals:
β
=0.02,
SE =0.01, t=1.18, p=0.236; bilinguals:
β
=
0.00, SE =0.02, t=
0.22, p=0.826). This is consistent
with previous literature showing that Stroop costs dissipate over time due to practice eects [83].
Table 3. Mean and standard deviation for Stroop performance by experimental half.
Monolinguals Bilinguals
First Half Second Half First Half Second Half
Accuracy
congruent 0.94 (0.07) 0.92 (0.12) 0.86 (0.09) 0.85 (0.11)
incongruent 0.90 (0.07) 0.94 (0.06) 0.80 (0.10) 0.86 (0.11)
Response Time (ms)
congruent 657.50 (58.58) 713.75 (66.03) 645.60 (55.56) 686.93 (57.49)
incongruent 684.68 (72.19) 680.44 (70.03) 664.38 (72.19) 648.28 (58.68)
In the correct-goal analysis (Table S3), the three-way interaction between preceding Stroop trial
type, sentence type, and experimental half was significant (
β
=
0.23, SE =0.09, t=
2.59, p=0.010).
During the first half of the experiment, the eect of preceding Stroop trial type was significant for
ambiguous sentences (
β
=0.13, SE =0.04, t=3.50, p<0.001), reflecting conflict adaptation. But
as Figure 6suggests, this modulation disappeared in the second half of the experiment (
β
=
0.03,
SE =0.04, t=
0.81, p=0.420). A similar pattern was observed in the incorrect-goal analysis (Table S4
and Figure 6). The three-way interaction between Stroop trial type, sentence type, and experimental
Brain Sci. 2019,9, 95 13 of 23
half was again significant (
β
=
0.23, SE =0.09, t=
2.59, p=0.010), indicating an eect of preceding
Stroop for ambiguous sentences in the first half (
β
=
2.24, SE =0.05, t=
2.24, p=0.026) but not in
the second half (
β
=0.04, SE =0.05, t=0.76, p=0.448) of the experiment. Although the three-way
interaction between Stroop trial type, sentence type, and group was again significant (
β
=
0.09,
SE =0.05, t=
2.07, p=0.038), the four-way interaction including experimental half was not (
β
=
0.06,
SE =0.09, t=
0.71, p=0.473), suggesting that the recovery eect following incongruent-ambiguous
sequences was similar in both groups (although numerically smaller in monolinguals) once time is
taken into account.
Brain Sci. 2019, 9, x FOR PEER REVIEW 14 of 24
Figure 6. Effect of conflict adaptation on the correct (top) and incorrect (bottom) goal in monolinguals
and bilinguals, split by the first and second half of the experiment. Greater values (i.e., more positive
for the correct goal, and more negative for the incorrect goal) on the y-axis reflect greater difference
between incongruent-ambiguous and congruent-ambiguous sequences and, therefore, greater
facilitation from incongruent Stroop sequences. Error bars indicate standard error of the mean. Error
bars indicate standard error of the mean.
3.3. Individual Differences in Working Memory
Although it is reasonable to assume that L1 and L2 comprehension make use of the same
cognitive resources, the incorrect-goal results suggest that differences might arise in the way those
resources are recruited. One way to further explore this idea is by examining whether (and how)
working memory ability mediates online comprehension, especially since working memory is often
found to modulate syntactic ambiguity in both L1 and L2 speakers [84,85]. To do this, we conducted
exploratory mixed model analyses for correct and incorrect goal fixations, adding O-span recall
scores as a predictor, and allowing it to interact with the fixed effects included in previous models.
Although no effects of working memory were found for correct-goal fixations, a strong pattern
of association between O-span and incorrect-goal fixations emerged for both groups (Table S5). There
was a significant interaction between group and O-span (β = 0.09, SE = 0.02, t = 3.60, p < 0.001),
indicating that, for monolinguals, higher O-span recall scores were associated with a decrease in
incorrect-goal fixations (β = 0.06, SE = 0.02, t = 2.88, p = 0.004). For bilinguals, however, higher O-
span was associated with an increase in incorrect-goal fixations (β = 0.02, SE = 0.01, t = 2.28, p = 0.024).
A three-way interaction between group, O-span, and experimental half (Figure 7) indicated that these
associations emerged for the first half (monolinguals: β = 0.10, SE = 0.03, t = 3.88, p < 0.001;
bilinguals: β = 0.04, SE = 0.01, t = 3.33, p < 0.001) but not for the second half (monolinguals: β = 0.02,
SE = 0.03, t = 0.81, p = 0.421; bilinguals: β = 0.01, SE = 0.01, t = 0.38, p = 0.703) of the experiment. These
patterns of associations indicate that working memory differentially impacted each group’s ability to
disengage incorrect-goal fixations.
Perhaps more interesting was the four-way interaction between sentence type, group,
experimental half, and O-span (β = 0.16, SE = 0.07, t = 2.18, p = 0.030), which yielded a three-way
interaction between sentence type, group, and O-span for the first experimental half (β = 0.16, SE =
0.07, t = 2.18, p = 0.030). As shown in Figure 8, for bilinguals, the effect of O-span in the first
experimental half was significant for ambiguous sentences (β = 0.07, SE = 0.02, t = 3.69, p < 0.001) but
not for unambiguous sentences (β = 0.02, SE = 0.02, t = 0.97, p = 0.333). The pattern of association for
monolinguals did not differ across conditions, indicating that the effect of working memory on
Figure 6.
Eect of conflict adaptation on the correct (top) and incorrect (bottom) goal in monolinguals
and bilinguals, split by the first and second half of the experiment. Greater values (i.e., more positive for
the correct goal, and more negative for the incorrect goal) on the y-axis reflect greater dierence between
incongruent-ambiguous and congruent-ambiguous sequences and, therefore, greater facilitation from
incongruent Stroop sequences. Error bars indicate standard error of the mean. Error bars indicate
standard error of the mean.
No reliable eects of preceding Stroop were observed for unambiguous sentences in either half
of the experiment. This was true for both correct-goal (first half:
β
=
0.04, SE =0.04, t=
1.22,
p=0.224; second half:
β
=
0.03, SE =0.04, t=
0.94, p=0.349) and incorrect-goal (first half:
β
=
0.06,
SE =0.04, t=
1.53, p=0.133; second half:
β
=0.01, SE =0.05, t=0.26, p=0.793) fixations. Moreover,
group did not interact with any of the other factors, suggesting that these modulations were similar
for both groups. Consistent with Hsu and Novick [
23
], these results suggest that Stroop-induced
conflict was responsible for modulating the ambiguity eect in both groups with respect to correct and
incorrect-goal fixations. They also suggest that the discrepancies between monolinguals and bilinguals
in the main analysis were due to dierences in the recruitment of task disengagement processes, and
not necessarily due to dierences in conflict monitoring abilities.
3.3. Individual Dierences in Working Memory
Although it is reasonable to assume that L1 and L2 comprehension make use of the same cognitive
resources, the incorrect-goal results suggest that dierences might arise in the way those resources are
recruited. One way to further explore this idea is by examining whether (and how) working memory
ability mediates online comprehension, especially since working memory is often found to modulate
syntactic ambiguity in both L1 and L2 speakers [
84
,
85
]. To do this, we conducted exploratory mixed
Brain Sci. 2019,9, 95 14 of 23
model analyses for correct and incorrect goal fixations, adding O-span recall scores as a predictor, and
allowing it to interact with the fixed eects included in previous models.
Although no eects of working memory were found for correct-goal fixations, a strong pattern of
association between O-span and incorrect-goal fixations emerged for both groups (Table S5). There
was a significant interaction between group and O-span (
β
=
0.09, SE =0.02, t=
3.60, p<0.001),
indicating that, for monolinguals, higher O-span recall scores were associated with a decrease in
incorrect-goal fixations (
β
=
0.06, SE =0.02, t=
2.88, p=0.004). For bilinguals, however, higher
O-span was associated with an increase in incorrect-goal fixations (
β
=0.02, SE =0.01, t=2.28,
p=0.024). A three-way interaction between group, O-span, and experimental half (Figure 7) indicated
that these associations emerged for the first half (monolinguals:
β
=
0.10, SE =0.03, t=
3.88, p<
0.001; bilinguals:
β
=0.04, SE =0.01, t=3.33, p<0.001) but not for the second half (monolinguals:
β
=
0.02, SE =0.03, t=
0.81, p=0.421; bilinguals:
β
=0.01, SE =0.01, t=0.38, p=0.703) of the
experiment. These patterns of associations indicate that working memory dierentially impacted each
group’s ability to disengage incorrect-goal fixations.
Brain Sci. 2019, 9, x FOR PEER REVIEW 15 of 24
fixation patterns was more global, whereas for bilinguals the effect was primarily driven by
ambiguous sentences.
Figure 7. Estimated effect of working memory on incorrect-goal fixations in the first (left) and second
(right) half of the experiment for bilinguals (n = 23) and monolinguals (n = 26). More positive values
on the x-axis indicate higher O-span recall scores. Shaded areas indicate standard error of the mean.
Figure 8. Estimated effect of working memory on incorrect-goal fixations for ambiguous sentences in
bilinguals (n = 23). More positive values on the x-axis indicate higher O-span recall scores. Shaded
areas indicate standard error of the mean.
4. Discussion
In an eye-tracking experiment examining cognitive control recruitment during sentence
comprehension, we found that Stroop-induced conflict facilitated recovery from syntactic ambiguity.
As a result, both monolinguals and bilinguals were better able to engage correct-goal interpretations
as they revised their initial misinterpretations in real time. This advantage in recovery was observed
only in the presence of a Stroop effect, which emerged during the first half of the experiment, but
disappeared afterwards. These findings directly replicate the results from Hsu and Novick [23].
Similarly, Stroop-related conflict modulated the ability to disengage incorrect-goal interpretations
Figure 7.
Estimated eect of working memory on incorrect-goal fixations in the first (left) and second
(right) half of the experiment for bilinguals (n=23) and monolinguals (n=26). More positive values
on the x-axis indicate higher O-span recall scores. Shaded areas indicate standard error of the mean.
Perhaps more interesting was the four-way interaction between sentence type, group, experimental
half, and O-span (
β
=0.16, SE =0.07, t=2.18, p=0.030), which yielded a three-way interaction between
sentence type, group, and O-span for the first experimental half (
β
=0.16, SE =0.07, t=2.18, p=0.030).
As shown in Figure 8, for bilinguals, the eect of O-span in the first experimental half was significant
for ambiguous sentences (
β
=0.07, SE =0.02, t=3.69, p<0.001) but not for unambiguous sentences
(
β
=0.02, SE =0.02, t=0.97, p=0.333). The pattern of association for monolinguals did not dier
across conditions, indicating that the eect of working memory on fixation patterns was more global,
whereas for bilinguals the eect was primarily driven by ambiguous sentences.
Brain Sci. 2019,9, 95 15 of 23
Brain Sci. 2019, 9, x FOR PEER REVIEW 15 of 24
fixation patterns was more global, whereas for bilinguals the effect was primarily driven by
ambiguous sentences.
Figure 7. Estimated effect of working memory on incorrect-goal fixations in the first (left) and second
(right) half of the experiment for bilinguals (n = 23) and monolinguals (n = 26). More positive values
on the x-axis indicate higher O-span recall scores. Shaded areas indicate standard error of the mean.
Figure 8. Estimated effect of working memory on incorrect-goal fixations for ambiguous sentences in
bilinguals (n = 23). More positive values on the x-axis indicate higher O-span recall scores. Shaded
areas indicate standard error of the mean.
4. Discussion
In an eye-tracking experiment examining cognitive control recruitment during sentence
comprehension, we found that Stroop-induced conflict facilitated recovery from syntactic ambiguity.
As a result, both monolinguals and bilinguals were better able to engage correct-goal interpretations
as they revised their initial misinterpretations in real time. This advantage in recovery was observed
only in the presence of a Stroop effect, which emerged during the first half of the experiment, but
disappeared afterwards. These findings directly replicate the results from Hsu and Novick [23].
Similarly, Stroop-related conflict modulated the ability to disengage incorrect-goal interpretations
Figure 8. Estimated eect of working memory on incorrect-goal fixations for ambiguous sentences in
bilinguals (n=23). More positive values on the x-axis indicate higher O-span recall scores. Shaded
areas indicate standard error of the mean.
4. Discussion
In an eye-tracking experiment examining cognitive control recruitment during sentence
comprehension, we found that Stroop-induced conflict facilitated recovery from syntactic ambiguity.
As a result, both monolinguals and bilinguals were better able to engage correct-goal interpretations as
they revised their initial misinterpretations in real time. This advantage in recovery was observed
only in the presence of a Stroop eect, which emerged during the first half of the experiment, but
disappeared afterwards. These findings directly replicate the results from Hsu and Novick [
23
].
Similarly, Stroop-related conflict modulated the ability to disengage incorrect-goal interpretations
during recovery from syntactic ambiguity, but this process began earlier for bilinguals. In fact, the
eect was not statistically reliable for monolinguals in the initial analysis, which is at odds with the
results reported by Hsu and Novick [23].
What factors account for such discrepancies? One possibility is that, at least in the context of
this paradigm, cognitive control procedures are only modulating correct-goal fixations, and that
the incorrect-goal eects are not ‘true’ eects. At first glance, this may seem feasible, given that
the eects reported in Hsu and Novick also appeared more stable for correct-goal fixations than for
incorrect goal-fixations. In fact, such a conclusion would seem tempting if one were to only examine
monolingual performance. However, the bilinguals in our study clearly showed a modulation of the
eects for incorrect-goal fixations, making this explanation unlikely. Regardless, the results in our
study do suggest that cognitive control (as manifested via Stroop-related conflict) dierentially aects
engagement and disengagement processes associated with sentence comprehension.
Another possibility is that the monolinguals were globally more skilled, as they had overall
higher correct-goal fixations and lower incorrect-goal fixations, as well as higher verbal fluency and
working memory than bilinguals (see Table 1). In fact, for monolinguals, working memory resources
mediated overall incorrect-goal fixations, such that those with higher working memory considered
the incorrect goal less during the revision phase. In previous research, both vocabulary size and
working memory have been associated with better linguistic abilities more generally [
84
,
86
,
87
]. In our
study, such skills may have reduced monolinguals’ susceptibility to experiencing ambiguity-related
conflict, thus reducing the need to engage cognitive control. This may also partially explain why in
Brain Sci. 2019,9, 95 16 of 23
the incorrect-goal analysis the dierence between ambiguous and unambiguous sentences remained
regardless of prior Stroop sequence (unlike bilinguals, who only showed an ambiguity eect for
sentences that were preceded by congruent Stroop sequences). In contrast to the monolingual sample
in our study, the sample in Hsu and Novick [
23
] may have been more heterogeneous with respect to
the linguistic and cognitive characteristics. However, it is not possible to directly assess this issue, as
no measures of general linguistic and non-linguistic ability (beyond the main task) were reported in
Hsu and Novick [
23
]. We therefore fully encourage future research to consider characterizing variation
in language processing in order to better understand the dynamics of conflict adaptation.
While the issue of improved global skills can partly account for the eects of ambiguity and
conflict adaptation that were observed in the incorrect-goal analysis, it does not explain why (and how)
the incorrect-goal results yielded dierences given that the same eects were similar for both groups in
the correct-goal analysis. Our position is that such discrepancies are more likely to primarily reflect
dierences in cognitive control recruitment strategies. For monolinguals, the process of disengaging
incorrect-goal interpretations following incongruent-Stroop sequences did not emerge until after the
disambiguating region (i.e., “onto the box”). For bilinguals, however, this process began earlier,
immediately after hearing the first prepositional phrase (i.e., “on the napkin”). This suggests that
both groups relied on dierent linguistic cues to initiate cognitive control recruitment. Monolinguals
may have used these resources more selectively and reactively, waiting for an explicit cue (i.e., the
disambiguating region) that would force a revision. Bilinguals, on the other hand, may have relied more
on a proactive strategy for the incorrect goal, utilizing cognitive control resources to not only recover
from ambiguity, but to also identify early linguistic cues (i.e., the omission of the complementizer
“that’s” during ambiguous trials) as quickly and eciently as possible.
Another important group discrepancy in the incorrect-goal analysis was observed in how working
memory modulated fixation patterns. Recall that for monolinguals, better working memory resulted
in reduced incorrect-goal fixations more generally, suggesting that these resources enabled those with
high working memory ability to be more ecient at disregarding incorrect-goal interpretations. This
is consistent with previous psycholinguistic research suggesting that working memory measures
reflect linguistic processing skills, rather than a separate domain-general construct [
88
90
]. Under this
experience-based view, better working memory results from increased exposure to the distributional
patterns that shape language use and comprehension, which positively aects the quality of linguistic
representations, thus leading to more ecient processing.
Despite the monolingual results, the eect of working memory for bilinguals was the exact
opposite: those with better working memory abilities considered incorrect-goal interpretations more,
and this was especially true for ambiguous sentences. This is consistent with studies showing that
individuals with greater working memory abilities become slower to process complex sentences
involving ambiguity [
89
,
91
]. Following the experience-based view, it has been argued that increased
linguistic experience strengthens the processing of frequently occurring linguistic patterns found in
the input, which can lead to greater processing costs when dealing with less frequent patterns [
92
].
However, such an explanation seems unlikely to fully account for the working memory results
reported here, since this would imply that the bilinguals in our study had greater cumulative linguistic
experience with their L2 than the monolinguals with their L1. Despite experiencing increased English
exposure due to L2 immersion, relative to monolinguals, bilinguals had overall reduced fixations on
the correct goal, as well as overall increased fixations on the incorrect goal. Bilinguals also showed
higher verbal fluency in their L1 relative to their L2, indicating that these individuals had, for the most
part, maintained L1 dominance. All of these results suggest that bilinguals were less experienced in
the L2 relative to monolinguals.
Therefore, it is dicult to attribute the group dierences of working memory primarily to
language experience and/or proficiency, since such an account would have predicted the same pattern
of association for both monolinguals and bilinguals. Instead, the bilingual results are consistent with
the idea that greater working memory resources increase susceptibility to interference stemming from
Brain Sci. 2019,9, 95 17 of 23
incompatible interpretations [
91
]. This interpretation is further supported by the finding that the eect
of working memory for bilinguals was primarily related to performance while listening to ambiguous
instructions. Therefore, we consider the possibility that working memory measures such as the O-span
reflect a combination of factors that include language-specific, as well as domain-general cognitive
control resources [
93
]. More importantly, these results suggest that the way in which those resources
are utilized will depend on experience as a proficient L2 speaker.
Unlike monolinguals, and unlike the results reported by Hsu and Novick [
23
], we found evidence
suggesting that incongruent-Stroop sequences were negatively aecting bilingual performance while
listening to unambiguous sentences. This pattern of results is consistent with previous research
suggesting that bilinguals may recruit and depend on cognitive resources more globally (i.e., in contexts
or in ways in which monolinguals would not recruit such resources). To illustrate, Blumenfeld and
Marian [
66
] found that for bilinguals, and not monolinguals, the magnitude of the Stroop eect (as
measured by a non-linguistic version of the Stroop task) was associated with the ability to resolve
within-language interference in a separate visual-world task. In another study by Ram
í
rez and
colleagues [
94
], bilingual, but not monolingual, infants engaged brain regions that are associated with
executive functions in order to successfully discriminate syllables from their two languages. Arguably,
this is because for bilinguals the act of learning and using a language is inherently a competitive
process [
61
]. In our study, the strategies observed in bilinguals may have further stemmed from the
fact that they were performing a highly demanding task in their less experienced (although highly
proficient) L2. In this sense, the group dierences observed with incorrect-goal fixation patterns should
not be taken as indicative of an advantage. If anything, monolinguals were more advantaged in terms
of characteristics and overall performance in the main task. Instead, such dierences likely reflect
adaptive changes that seek to maximize the eciency of goal-directed behavior.
More generally, the incorrect-goal results for bilinguals also revealed a dissociation in the
recruitment of engagement and disengagement processes, suggesting that it was the disengagement
portion that was most eortful, therefore requiring a greater need for cognitive control. This is
consistent with recent studies highlighting the role of disengagement for bilinguals in linguistic and
non-linguistic contexts. For example, Blanco-Elorrieta and colleagues [
95
] recorded brain activity of a
group of bimodal bilinguals (who could sign and speak at the same time) while performing a language
switching task. The results showed an engagement of (and stronger connectivity between) brain regions
associated with domain-general cognitive/attentional control when switching from a ‘simultaneous’
language-context (i.e., a context where both languages were used simultaneously) to a single-language
context, but not when switching contexts in the opposite direction (i.e., from a single-language context
to a simultaneous context). Similar to this pattern was the result in the present study showing increased
incorrect-goal fixations for bilinguals in the incongruent-unambiguous condition (where participants
transitioned from a conflict-prone condition to a less demanding condition). Although one must be
careful in drawing comparisons between studies with dierent methodologies (language vs. task
switching) and between dierent bilingual populations (unimodal vs. bimodal bilinguals), the overall
pattern of results from Blanco-Elorrieta and colleagues [
95
], as well as ours, seem to suggest that the
process of ‘moving away’ from conflict is critical for understanding the consequences of using more
than one language.
The idea that bilingualism impacts disengagement has been expressed in recent work investigating
dierences in attentional control between bilinguals and monolinguals. In another recent study by
Grundy and Bialystok [
68
], monolinguals and unimodal bilinguals performed a non-linguistic switching
task containing univalent sequences (where each task had its unique set of features) and bivalent
sequences (where a given trial had a feature that overlapped with a previous trial from one of the other
tasks). Electrophysiological results indicated that, after experiencing conflict in the bivalent sequences,
bilinguals resolved the post-conflict costs more quickly and more eciently. This finding is similar to
the main results reported by Blumenfeld and Marian [
66
]. In this study, monolinguals and bilinguals’
eye-movements were tracked using a visual world paradigm. Participants viewed a display that
Brain Sci. 2019,9, 95 18 of 23
contained within-language phonological competitors, which were followed by priming probe trials that
measured the degree of residual phonological interference. On picture-display trials, eye-movements
results showed that both groups were similarly aected by the phonological competitors. However, on
subsequent priming probe trials, bilinguals’ behavioral performance was less aected by the residual
interference that had emerged from the phonological competitors, suggesting that bilinguals were able
to resolve prior linguistic conflict more quickly in order to engage in new task-relevant information.
This is perhaps the study that aligns the closest with the results from our study, both suggesting
dierences in the timing of cognitive control involvement. Taken together, these studies indicate that
there are circumstances in which bilinguals are able (or required) to use cognitive control procedures
to disengage attention more eciently, be it faster conflict resolution or reduced interference costs.
A final important issue to consider in the current set of results is the role of language immersion
status. The bilinguals tested in the present study all came from a non-English speaking country, but
became immersed in an English context later in their lives as part of their college education, while still
maintaining dominance in their L1 (despite having restricted L1 exposure and use, as Table 1suggests).
A group of bilinguals with similar characteristics was examined in Zirnstein and colleagues [
14
],
who found that, for L2 immersed bilinguals (who were also L1 dominant), the ability to generate
(and recover from) prediction errors in the L2 was mediated by a combination of cognitive control
and language regulatory abilities. As such, the results by Zirnstein and colleagues [
14
] suggested
that the experiences associated with becoming immersed in an L2 environment seems to impose
unique demands on the language and cognitive system. Although preliminary, the findings reported
here converge with this idea, and tentatively suggest that immersion status may at least be partially
responsible for the group dierences in cognitive control recruitment strategies.
5. Conclusions
The present study provides support for the notion of adaptive changes in cognitive control as a
function of language experience, but in a dierent form. Namely, our findings tentatively suggest that
there may be a dynamic interplay between the long-term consequences of using a second language
and the short-term recruitment of domain general resources that mediate processing in that same
language. However, we note that the way in which this interplay plays out may vary across dierent
bilingual populations.
It is also worth noting that the bilinguals in our study spoke dierent L1s, making it dicult to
examine whether there were aspects of the L1 that influenced conflict adaptation in the L2. For example,
it is possible that bilinguals whose languages are more likely to create conditions of cross-language
conflict are also more likely to create a greater need for cognitive control recruitment. Likewise, we
acknowledge the limitations that may come from comparing monolinguals and bilinguals [
96
], as
more recent research suggests that dierent bilingual language experiences can come to have dierent
consequences for both cognitive [
97
100
] and language [
101
] processes. However, it is also worth
pointing out that there are situations in which such comparisons reveal important aspects of language
and cognitive functioning that may be harder to interpret otherwise, at least initially.
As such, our goal in this paper was not to identify advantages or to single out individual cognitive
mechanisms. Rather, our aim was to exploit how multiple cognitive processes coordinate with one
another to support language processing in real time, using a dierent framework from what many
of the previous bilingual studies have used. We believe that future research will need to adopt a
similar approach in order to develop a causal theory of bilingualism and its consequences for language
and cognition.
Supplementary Materials:
The following are available online at http://www.mdpi.com/2076-3425/9/5/95/s1, Figure
S1: Mean proportion of fixations on the correct goal over time as a function of ambiguity for monolinguals (top)
and bilinguals (bottom). Higher values on the y-axis indicate more looks to the correct goal. Colored error bars
indicate 95% confidence intervals, Figure S2: Mean proportion of fixations on the correct goal over time as a
function of ambiguity and preceding Stroop trial type for monolinguals (top row) and bilinguals (bottom row).
Colored error bars indicate 95% confidence intervals, Figure S3: Mean proportion of fixations on the incorrect
Brain Sci. 2019,9, 95 19 of 23
goal over time as a function of ambiguity. Higher values on the y-axis indicate more looks to the incorrect goal.
Colored error bars indicate 95% confidence intervals, Figure S4: Mean proportion of fixations on the incorrect goal
over time as a function of ambiguity and preceding Stroop trial type. Colored error bars indicate 95% confidence
intervals, Table S1: Summary of mixed model analysis for correct goal fixations, Table S2: Summary of mixed
model analysis for incorrect goal fixations, Table S3: Summary of mixed model analysis for correct goal fixations
by experimental half, Table S4: Summary of mixed model analysis for incorrect goal fixations by experimental half,
Table S5: Summary of mixed model analysis examining the eect of working memory on incorrect goal fixations.
The stimuli materials have been made publicly available by Hsu and Novick [23].
Author Contributions:
Conceptualization, C.A.N.-T. and J.F.K.; Methodology, C.A.N.-T.; Formal Analysis,
C.A.N.-T.; Investigation, C.A.N.-T. and D.L.G.; Resources, J.F.K.; Writing—Original Draft Preparation, C.A.N.-T.
and D.L.G.; Writing—Review & Editing, C.A.N.-T., D.L.G., V.C., and J.F.K.; Visualization, C.A.N.-T. and D.L.G.;
Supervision, V.C. and J.F.K.; Project administration, C.A.N.-T., V.C., and J.F.K.; Funding acquisition, C.A.N.-T. and
J.F.K.
Funding:
The writing of this paper was supported in part by the following grants: NSF Grants BCS-1535124,
OISE-1545900, and an NIH Grant HD082796 to J.F.K.; NSF BCS-1824072 and NSF GRFP DGE-1255832 to C.A.N.-T.
Acknowledgments: This work was not supported by any other funding.
Conflicts of Interest: The authors declare no conflict of interest.
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... We then define the Traits and States approaches before turning to some methodological limitations of approaches that examine cognitive abilities as relatively fixed traits to be compared across groups. To address these limitations, we describe a complementary approach in which researchers manipulate either the linguistic context to observe the consequence of these manipulations on cognitive performance (e.g., Adler et al., 2020;Wu & Thierry, 2013) or an individual's cognitive state to observe its influence on language processing (e.g., Navarro-Torres et al., 2019). By employing a States approach, language scientists can ask questions about how the dynamics of language processing impact other cognitive abilities (and vice versa) on a moment-to-moment basis. ...
... The conflict-adaptation approach has also been implemented to observe whether the relative engagement status of a bilingual's cognitive-control state influences their real-time language processing, in particular, their ability to recover from temporary misinterpretations (Navarro-Torres et al., 2019). To manipulate cognitive control, one study interleaved congruent and incongruent Stroop trials with a language task in which participants had to follow instructions that were either unambiguous or temporarily ambiguous and ripe for misanalysis (e.g., "Put the frog on the napkin onto the box," where "on the napkin" is initially interpreted as a destination but must be revised once "onto the box" unfolds, conflicting with that interpretation). ...
... This replicates findings in monolinguals (e.g., Hsu & Novick, 2016;Hsu et al., 2021;Thothathiri et al., 2018) and demonstrates how parsing and interpretation can be rapidly affected by different states of cognitive engagement. Moreover, when comparing the effect of variable states in bilinguals to monolinguals, the data revealed that bilingual listeners began disambiguating the ambiguous sentences earlier than monolingual listeners, suggesting group differences in the timing of cognitive-control engagement (Navarro-Torres et al., 2019). This study exemplifies the value that a combined States and Traits approach can have, especially to consider the effects of both immediate state-based effects and lifetime experience. ...
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The study of how bilingualism is linked to cognitive processing, including executive functioning, has historically focused on comparing bilinguals to monolinguals across a range of tasks. These group comparisons presume to capture relatively stable cognitive traits and have revealed important insights about the architecture of the language processing system that could not have been gleaned from studying monolinguals alone. However, there are drawbacks to using a groupcomparison, or Traits, approach. In this theoretical review, we outline some limitations of treating executive functions as stable traits and of treating bilinguals as a uniform group when comparing to monolinguals. To build on what we have learned from group comparisons, we advocate for an emerging complementary approach to the question of cognition and bilingualism. Using an approach that compares bilinguals to themselves under different linguistic or cognitive contexts allows researchers to ask questions about how language and cognitive processes interact based on dynamically fluctuating cognitive and neural states. A States approach, which has already been used by bilingualism researchers, allows for cause-and-effect hypotheses and shifts our focus from questions of group differences to questions of how varied linguistic environments influence cognitive operations in the moment and how fluctuations in cognitive engagement impact language processing.
... The O-span is a complex working memory task thought to recruit procedures associated with the control of attention (Engle & Kane, 2004;Linck et al., 2013;Shipstead et al., 2015Shipstead et al., , 2016 and has shown to account for variability in language processing (e.g. Bice & Kroll, 2021;Navarro-Torres et al., 2019;Tanner & Van Hell, 2014; see Linck et al., 2013 for a meta-analytic review). Verbal fluency tasks, on the other hand, are unique in that they may reflect a combination of linguistic and domain-general control processes by imposing lexical-semantic constraints on how speakers self-generate words. ...
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... Although some studies (e.g., Bultena et al., 2015;Wang, 2015) argued that differences in cognitive control paradigms (top-down control vs bottom-up control) might be employed in codeswitching production and comprehension, the involvement of cognitive control beyond language domain in bilingual language comprehension has been broadly examined and supported. Specifically, studies on both syntactic complex or ambiguous sentences (e.g., Hsu & Novick, 2016;Navarro-Torres et al., 2019;Teubner-Rhodes et al., 2019) and bilingual sentences with codeswitches (e.g., Adler et al., 2020;Bosma & Pablos, 2020;Wang, 2015) indicated the role of cognitive control in facilitating successful comprehension. ...
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The Adaptive Control Hypothesis (ACH, Green & Abutalebi, 2013) proposed that different interactional contexts place different demands on cognitive processes for bilinguals. However, how cognitive control processes dynamically adapt to comprehending and producing languages in different interactional contexts is still poorly understood. This study investigated how different language interactional contexts (i.e., single-language, dual-language and dense code-switching) modulate cognitive control in bilingual language comprehension. Inhibitory control in 36 Chinese-English bilinguals was examined through flanker tasks. Participants’ language and cognitive control statuses in the three interactional contexts were manipulated through three different types of dialogue-listening. After they listened to each type of dialogue, they were instructed to complete the flanker task and answer ten comprehension questions related to the dialogue. Repeated-measures ANOVA compared participants’ reaction times and response accuracy in flanker tasks across the three interactional contexts. Similarly, their language comprehension performance across different interactional contexts were also compared. Both the dual-language and Chinese single-language contexts showed significant facilitatory effects on participants’ inhibitory control efficiency. Furthermore, participants performed more accurately on answering comprehension questions in the Chinese single-language context, indicating the dominant language effects on modulating bilinguals’ language comprehension performance. Such effects were not found in the dense code-switching and dual-language contexts. This study provided empirical evidence for confirming the Adaptive Control Hypothesis by revealing the facilitatory effects of dual-language context on cognitive control in bilingual language comprehension process. In general, it is an attempt to explore the associations between interactional contexts and cognitive control through bilingual language and cognitive processing manipulations.
... Specifically, increased cognitive control ability related to reduced prediction error costs but only for bilinguals with better L1 regulation. Moreover, a visual world study by Navarro-Torres et al. (2019) found that L2-immersed bilinguals living in Edinburgh proactively disengaged from incorrect interpretations of syntactically ambiguous sentences by relying on early linguistic cues to preempt potential ambiguity. Similar associations have been observed in language production. ...
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... Recent studies suggest that individuals engage a combination of languagerelated and domain-general resources to achieve language processing. For example, Navarro-Torres, Garcia, Chidambaram, & Kroll (2019) conducted an eye-tracking experiment with English monolinguals and bilinguals who spoke L2 English to examine syntactic ambiguity in comprehension (e.g. by listening to goal-directed sentences such as "Put the frog on the napkin onto the box" while dragging the corresponding objects on a computer screen). The authors used a cross-task adaptation paradigm that interleaved Stroop sequences with the sentence comprehension task, allowing them to measure how Stroop-related conflict affected recovery from syntactic ambiguity on a trial-by-trial basis. ...
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... It is possible that the lack of elicited negative affect in that design is behind the lack of evidence for the congruency sequence effect in Experiment 2. Here, it is relevant to note that our results should not be generalized to other experimental arrangements. It is possible that different designs can be more sensitive to detect the cross-task congruency sequence effect [37,[39][40][41]. Future research should consider applying cross-task designs to test the predictions of the Affective Signaling Hypothesis. ...
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Exploring the mechanisms of cognitive control is central to understanding how we control our behaviour. These mechanisms can be studied in conflict paradigms, which require the inhibition of irrelevant responses to perform the task. It has been suggested that in these tasks, the detection of conflict enhances cognitive control resulting in improved conflict resolution of subsequent trials. If this is the case, then this so-called congruency sequence effect can be expected to occur in cross-domain tasks. Previous research on the domain-generality of the effect presented inconsistent results. In this study, we provide a multi-site replication of three previous experiments of Kan et al . (Kan IP, Teubner-Rhodes S, Drummey AB, Nutile L, Krupa L, Novick JM 2013 Cognition 129 , 637–651) which test congruency sequence effect between very different domains: from a syntactic to a non-syntactic domain (Experiment 1), and from a perceptual to a verbal domain (Experiments 2 and 3). Despite all our efforts, we found only partial support for the claims of the original study. With a single exception, we could not replicate the original findings; the data remained inconclusive or went against the theoretical hypothesis. We discuss the compatibility of the results with alternative theoretical frameworks.
... While a number of wellknown measures of cognitive skill have been investigated, their predictive power in what concerns online processing appears to be limited. For example, greater engagement of executive control has been found to be associated with efficiency in recovery from initial misinterpretations, both in the L1 (Novick et al., 2013;Hsu and Novick, 2016) and in the L2 (Navarro-Torres et al., 2019). However, the role of executive control in such studies is most theoretically relevant in cases in which conflicting representations require controlled selection, specifically, rather than in processing across the board. ...
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