Article Figures & Data
Figures
- Figure 1.
Task-switching paradigm. Tasks were indicated via cue words. In shape blocks, participants decided if a stimulus was a circle or square. In color blocks, participants decided if a stimulus was red or blue. In switch blocks, participants alternated between shape and color decisions.
- Figure 2.
Behavioral results from Experiment 2. Mean performance data and switch costs according to age group and language group. For proportional RT switch costs, the long horizontal bar indicates an effect of age group, and the short horizontal bar indicates an age group by language group interaction. *p = 0.056, **p < 0.01, ***p < 0.001.
- Figure 3.
fMRI results. A, Voxelwise conjunction activation map of the switch–nonswitch contrast across groups. B, Mean BOLD switch costs for each group in each of the seven ROIs identified in the conjunction results. The long horizontal bars indicate effects of age group, and the short horizontal bars indicate age by language interactions. *p < 0.007, **p < 0.001.
- Figure 4.
Relationship between neural and behavioral switch costs in older adults. Regression plots show the significant correlations between neural switch costs and proportional RT switch costs or error switch costs in the three regions showing age by language group interactions in Figure 3B. Each circle represents one of the 20 participants in each older adult (monolingual or bilingual) group.
- Figure 5.
Effect of language group on switching activation. Voxelwise contrast indicated increased activation in lifelong bilinguals compared with monolinguals in left MTG. Regression plots show the nonsignificant correlations between neural switch costs and proportional RT switch costs or error switch costs in the left MTG. Each circle represents one of the 20 participants in each older adult (monolingual or bilingual) group.
Tables
- Table 1.
Group means, SDs (in parentheses), and p values for demographic and neuropsychological scores for Experiment 2
Younger Older p Values Monolingual Bilingual Monolingual Bilingual Age group Language group Age × language Age 32.2 (3.3) 31.6 (4.3) 64.4 (5.1) 63.9 (4.0) <0.001 0.92 0.74 Education 17.1 (2.6) 18.3 (2.5) 17.5 (2.6) 17.4 (2.2) 0.37 0.38 0.23 ISP 26.1 (5.3) 21.7 (10.1) 21.6 (7.0) 19.7 (8.7) 0.12 0.19 0.58 PPVT 107.2 (11.8) 101 (10.7) 110.1 (13.9) 105.3 (18.5) 0.28 0.13 0.85 IQ 126.6 (23.3) 121.3 (15.6) 124.6 (20.2) 127.6 (22.5) 0.64 0.80 0.38 DF 10.7 (2.5) 10.8 (2.4) 10.6 (2.0) 9.7 (2.1) 0.22 0.50 0.38 DB 10.4 (2.8) 10.3 (3.1) 10.5 (2.1) 10.5 (3.2) 0.83 0.96 0.93 DB, Digits backward; DF, digits forward; IQ, Cattell Culture Fair Intelligence Test; ISP, Index of Social Position; PPVT, Peabody Picture Vocabulary Test. Values for the PPVT, IQ, and DB are age-scaled scores.
Monolingual Bilingual Younger Languages spoken English English + African language (Luo, Swahili), French, German, Indian language (Gujarati, Hindi), Greek, Spanish, Turkish, Mandarin Percentage born in United States 95% 25% Older Languages spoken English English + African language (Igbo, Swahili), Filipino, French, German, Indian language (Gujarati, Hindi, Konkani), Spanish Percentage born in United States 85% 25% Region X Y Z BA z-score Left DLPFC −46 26 28 46/9 5.82 Right DLPFC 44 24 26 46/9 4.84 Left VLPFC −48 22 6 44/45 4.62 Right VLPFC 45 20 0 45/47 5.23 ACC −2 38 12 24/32 5.22 Left SMG −40 −60 42 40 4.44 Right SMG 42 −56 38 40 4.64 ACC, Anterior cingulate cortex; BA, Brodmann area; DLPFC, dorsolateral prefrontal cortex; SMG, supramarginal gyrus; VLPFC, ventrolateral prefrontal cortex.
- Table 4.
Task-switching activation means, SDs (in parentheses), and p values for primary common regions
Younger Older p values Monolingual Bilingual Monolingual Bilingual Age group Language group Age × language Left DLPFC 0.33 (0.29) 0.38 (0.15) 0.64 (0.24) 0.44 (0.16) <0.007 0.12 <0.007 Left VLPFC 0.19 (0.18) 0.24 (0.12) 0.45 (0.19) 0.26 (0.14) <0.007 0.09 <0.007 Right DLPFC 0.18 (0.14) 0.25 (0.17) 0.39 (0.20) 0.36 (0.12) <0.007 0.84 0.17 Right VLPFC 0.23 (0.17) 0.20 (0.15) 0.41 (0.18) 0.32 (0.14) <0.007 0.10 0.48 ACC 0.22 (0.22) 0.28 (0.20) 0.53 (0.23) 0.31 (0.19) <0.007 0.08 <0.007 Left SMG 0.23 (0.20) 0.26 (0.22) 0.32 (0.21) 0.25 (0.18) 0.46 0.61 0.24 Right SMG 0.35 (0.18) 0.37 (0.24) 0.39 (0.24) 0.40 (0.16) 0.45 0.72 0.76 L, Left; R, right; ACC, anterior cingulate cortex; DLPFC, dorsolateral prefrontal cortex; SMG, supramarginal gyrus; VLPFC, ventrolateral prefrontal cortex.
