Bialystok et al. (2004)
Authors: Philippa Rai (prai@ucsd.edu) and Kelli Star (kestarr@ucsd.edu)
Publication Date: May 13th 2014
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Cognitive Aging

Cognitive aging research has been one of the most researched elements in the neuroscience world. What exactly is cognitive aging though? Cognitive aging is age-related declines in our cognitive abilities. Cognitive aging does not effect all of our mental abilities, for example our habitual procedures or general world knowledge. Cognitive aging does effect the following:
  • Executive Control Functions
  • Perceptual Processing
  • Selective Attention
  • Inhibition

To read more information on Cognitive Aging go to this link.

Current Research

An important question research has been asking "How do we stop or slow down cognitive aging as we age?" To answer this question, researchers have began to investigate bilingualism. Previous research has reported that bilinguals have been show to have cognitive advantages in effective controlled processing. This is due to the fact that bilinguals have two languages competing with one another, this requires bilinguals to have a high inhibitory control mechanism. Bilinguals have to be able to suppress the non-relevant language in order to use the relevant language fluently. This gives bilinguals practice in exercising inhibiton, which can then be generalized across other cognitive domains.


Here is a video explaining some benefits of bilingualism.

Research Question
Does bilingualism reduce the negative effects of aging on cognitive control in older adults?

Simon Task
Bialystok decided to test executive controls processes with the Simon task. The Simon task could allow for all ages to be tested with it because it is there is rarely any content used but still task requires the use of cognitive processes. Colored stimuli was shown on either the right or the left side of the computer screen. Each of the two colored stimulus was paired with a response key that would be on one of the two sides of the keyboard.
Congruent trials vs Incongruent Trials
  • Congruent trials: The response key was located on the same side as the colored stimuli
  • Incongruent trials: The response key was located on the opposite side of the colored stimuli

"Simon Effect"- An increased reaction time (RT) to respond in the incongruent trial. Can be an indication of inhibitory processing and working memory.

Study 1

Researchers wanted to replicate the original simon task study, this time with younger and older adults monolingual and bilinguals.

Participants
40 participants in two different groups, language and age. The younger age group (N=20) was from 30-54 years of age (M=43) while the older age group (N=20) ages ranged from 60-88 years of age (M=71.9). Monolingual English speakers from Canada had no other previous exposure to language. Bilingual Tami-English speakers lived in India, at the age of 6 started to speak English and spoke bilingually from there on out.

Task and Procedure
Simon Task- Participants were instructed when seeing a blue box the should press the left shift key and when seeing a red square they should press the right shift key. Participants started with eight practice trials until they achieved an error free performance. Then the participants had 28 experimental trials, where 1/2 of the trials were incongruent trials and the other 1/2 was incongruent trails (in a randomized order.)

Results
Background tests showed participants were consistent on measures of spatial and verbal intelligence.

Simon Task- Three-Way analysis for language (monolingual, bilingual),
age group (older, younger) and congruency (congruent, incongruent) showed:
  • Accuracy- More accuracy on congruent trials (p<.01) ;the differences was smaller for the younger adults.
  • Age group- Younger adults were faster than monolinguals (p<.01)
  • Language group- Bilinguals were faster than monolinguals (p<.01)
  • Simon Effect- was greater for monolingual participants and the older group
This results are summarized in Table 2 below:
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Discussion
However the Simon Task showed that bilinguals were consistently faster in their RT compared to the monolinguals and showed less of a Simon effect. For the older bilinguals participants, they were able to avoid the increase in errors that was predicted for an increase in age while monolinguals did not. This showed older adults and monolinguals were less able to inhibit the influence on the incongruent trials.

Study 2

Researchers wanted to change methodology to search for what could be the bilingual advantage.

Participants
There was 94 participants, split into an age group and a language group. First group of younger adults (N=64) ranged from 30-58 (M=42.6) years of age and were divided equally into English monolinguals (N=34) and Tamil-English Bilinguals (N=20) or English-Cantonese Bilinguals (N=12) l. The second group (N=30) of older adults ranged from 60-80 (M=70.3) years of age and were divided equally into English monolinguals (N=15) and Tamil-English bilinguals (N=9) or English-French Bilinguals (N=6).

Task and Instruments
.Simon tasks- Four conditions
  • Condition A- two colors-center (control)
  • Condition B-two colors-side
  • Condition C-Four colors-center, each color appeared in center- placed greater demand on working memory
  • Condition D- Side 4 :Four colors, each color appear on side

Results


Simon Task Conditions
The results are summarized in the Figures below:
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  • Central Positioning and the condition with two colors was faster
  • Age- Younger adults were faster overall
  • Language- Results were similar in Center-2 condition, however overall in the other three condition bilinguals preformed faster than the monolinguals
  • Simon Effects- higher in older adults and monolinguals

Discussion
Major Finding: Monolingual and Bilingual performed identical in control condition, then bilinguals achieved faster response times in all other conditions. Bilinguals with more stimuli was able to successful hold in it in their working memory.

Decade Analysis
  • Monolinguals- Their performance on the task remained consistent until age 60 than their RTs increased
  • Bilinguals- Their Performance on the task remained consistent until age 70 than their RTs increased

Study 3

Purpose was to the determine whether the monolingual and bilingual group would converge in performance on the task after enough practice

Participants
20 adults participants raging from 30-55 (M=40.6) years of age. Half of the participants were French-English bilinguals and the other half was English monolinguals (38.8) leaving in same Canadian community.

Tasks and procedure
Same five tasks for study 2.
Two conditions for simon tasks for study 2 was administrated. These represented in 10 consecutive blocks of 24 trials with a short break.

Results
The results are summarized in the Figure below:
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Bilinguals maintained faster RT in the beginning of the blocks, then the two groups converged towards the last two blocks of trials.
Simon Effect- Bilinguals had an advantage in the beginning but then both groups leveled out.

Discussion
Monolinguals gradually improved, by the end they demonstrated what the bilinguals demonstrated in the beginning after practicing.

General Discussion

In the studies, it was shown that bilinguals produced less of a smaller Simon effect, showing that their experience managing dual languages can reduce age-related declines in their inhibitory process. Overall in all three studies bilinguals' performance was greater compared to the monolinguals' performance, even on the incongruent trials, which indicates a broader effect.
What can this conclude?
  • Bilinguals may have greater executive processes- in attention, selection, inhibition, which can help reduce cognitive aging
  • Bilingualism effects may be more general than previously thought, further research in this topic should be done

Discussion Questions

1. Do you think the Simon task was an effective measure for cognitive control? How could it have been improved?
2. Do you feel that changing the amount of colors done in the Simon task helped the study in telling the difference between monolinguals and biliniguals?
3. Do you feel confident in the results of the study? Do you believe that bilingualism can actually be a protective measure again cognitive aging?

References

Bialystok, E., & et al. (2004). Bilingualism, Aging, and Cognitive Control: Evidence From the Simon Task .Psychology and Aging, 19(2), 290-303.