Table 5: Mixed model results of four longitudinal studies.

OCTO-TwinLBLSSLSVLS
bSE 𝑃 bSE 𝑃 bSE 𝑃 bSE 𝑃

Reasoning

Intercept10.890.55<.0121.430.53<.0114.650.17<.019.520.59<.01
 Age−0.330.12.01−0.620.04<.01−0.350.01<.01−0.260.02<.01
 Female0.680.67.311.860.77.021.57 0.24<.01−0.150.31.62
 Education0.560.13<.011.300.13<.010.520.04<.010.320.05<.01
 Social activity 1.010.28<.010.080.25.740.110.08.140.050.02.03
 Age × social activity−0.020.11.830.080.03<.010.010.01.150.000.00.40
 Education × social activity0.040.11.71−0.040.08.67−0.030.03.26−0.010.01.69
Slope−0.440.08<.01−0.500.08<.01−0.250.02<.01−0.250.03<.01
 Age−0.020.02.28−0.030.01<.01−0.010.00<.01 −0.010.00<.01
 Female0.080.09.420.080.11.480.010.02.510.010.03.76
 Education0.010.02.56−0.050.02<.01−0.01 0.00.11−0.010.00.08
 Social activity0.060.05.240.040.04.300.020.01.020.000.00.44
Social activity change0.650.15<.010.040.17.830.130.06.040.030.00.02

Fluency

Intercept31.010.61<.0136.110.44<.0111.50.56<.01
 Age−0.300.05<.01−0.340.04<.01−0.100.03<.01
 Female3.390.88<.013.360.60<.010.510.36.16
 Education1.050.15<.011.310.11<.010.630.05<.01
 Social activity 0.990.29<.010.240.19.200.040.03.12
 Age × social activity0.030.03.400.000.02.89−0.010.01.29
 Education × social activity−0.110.10.240.040.07.59−0.010.01.07
Slope−0.240.11.02−0.430.04<.01−0.120.03<.01
 Age−0.030.01<.01−0.020.00<.01−0.010.01<.01
 Female−0.200.15.180.110.05.020.060.04.16
 Education−0.010.03.65−0.010.01.15−0.010.01 .74
 Social activity0.070.05.150.020.02.260.010.01.83
Social activity change0.730.25<.010.180.15.210.06 0.02<.01

Memory

Intercept8.700.32<.0110.800.20<.0111.560.13<.0117.280.41<.01
 Age−0.200.06<.01−0.190.02<.01−0.180.01<.01−0.190.02<.01
 Female0.990.39.011.500.28<.011.590.17<.011.450.27<.01
 Education0.340.07<.010.290.05<.01 0.320.03<.010.310.04<.01
 Social activity 0.340.07<.010.000.09.980.140.06.010.060.02<.01
 Age × social activity−0.090.06.100.010.0.610.000.01.51−0.010.01.95
 Education × social activity0.010.06.91−0.020.03.57−0.020.02.18−0.010.01.19
Slope−0.260.07<.01−0.180.05<.01−0.170.01<.01−0.270.03<.01
 Age0.000.02.970.000.01.46−0.010.00<.01−0.010.01<.01
 Female0.050.08.55−0.030.07.640.020.02.15−0.02 0.03.56
 Education−0.010.02.730.010.01.400.000.00.58−0.010.01.15
 Social activity0.070.04.070.030.02.150.010.01.370.010.01.25
Social activity change0.470.11<.010.110.10.300.120.06.030.060.01<.01

Semantic knowledge

Intercept30.490.86<.0138.190.54<.0124.080.22<.0143.770.71<.01
 Age−0.550.17<.01−0.280.04<.010.02 0.02.350.080.03.02
 Female−4.201.05<.011.190.78.130.700.30.02−0.010.46.99
 Education1.430.19<.011.030.14<.011.120.05<.010.770.07<.01
 Social activity 0.870.40.030.100.25.70−0.220.10.020.020.03.63
 Age × social activity−0.100.15.470.080.03<.01−0.010.01.610.010.01.77
 Education × social activity0.030.17.84−0.060.09.50−0.050.03.150.010.01.61
Slope−0.850.11<.01−0.460.08<.01−0.120.01<.01−0.160.03 <.01
 Age−0.050.02.03−0.040.01<.01−0.010.00<.01−0.010.01<.01
 Female0.190.13.150.120.12.300.060.02<.01 0.030.04 .42
 Education0.030.03.29−0.020.02.320.000.00.78−0.010.01 .18
 Social activity0.110.07.120.010.04.950.010.01.01−0.010.01 .40
Social activity change0.860.19<.010.170.17.330.080.06.13−0.010.01.93

Values represent model coefficients and their standard error. Across all studies, time was measured in years since baseline visit and activity change was entered as a time-varying covariate. All other variables represent baseline measurements alone, in interaction with one another, or in interaction with time.