Aging and Sequential Strategy Interference: A Magnetoencephalography Study in Arithmetic Problem Solving

Abstract

This study investigated age-related changes in the neural bases of sequential strategy interference. Sequential strategy interference refers to decreased strategy interference (i.e., poorer performance when the cued strategy is not the best) after executing a poorer strategy relative to after a better strategy. Young and older adults performed a computational estimation task (e.g., providing approximate products to two-digit multiplication problems, like 38 × 74) and were matched on behavioral sequential strategy interference effects. Analyses of magnetoencephalography (MEG) data revealed differences between young and older adults in brain activities underlying sequential strategy interference. More specifically, relative to young adults, older adults showed additional recruitments in frontal, temporal, and parietal regions. Also, age-related differences were found in the temporal dynamics of brain activations, with modulations occurring both earlier and later in older than young adults. These results suggest that highly functioning older adults rely on additional mechanisms to process sequential strategy interference as efficiently as young adults. Our findings inform mechanisms by which highly functioning older adults obtain as good performance as young adults, and suggest that these older adults may compensate deleterious effects of aging to efficiently execute arithmetic strategies.

Keywords: aging; arithmetic; cognitive control; magnetoencephalography; strategy execution.

Figure 1

Events within a sequence. The letters “BH” (i.e., standing for “down-up” in French) cued participants to use the mixed-rounding down-up strategy, and the letters “HB” (i.e., standing for “up-down” in French) prompted participants to use the mixed-rounding up-down strategy.

Figure 2

Mean solution times for current better strategy and poorer strategy problems following better strategy or poorer strategy problems in young and older adults. Error bars represent S.E.M. **p < .01, ns, non-significant.

Figure 3

Differences in z-scored amplitudes, on current poorer strategy problems, between previous better strategy problems and following previous poorer strategy problems in older adults comparatively in young adults (Hinault et al., 2017). In older adults, when the second problems were preceded by the execution of the poorer strategy, significant brain activations were found in ACC (Anterior Cingulate Cortex), LIFJ (Left Inferior Frontal Junction), RIFJ (Right Inferior Frontal Junction), RPFC (Right Prefrontal Cortex), LMFG (Left Median Frontal Gyrus), RSFG (Right Superior Frontal Gyrus), LSFG (Left Superior Frontal Gyrus), and RSTG (Right Superior Temporal Gyrus) between −400 and −200 ms before the second problems display and between 500 and 650 ms following the onset of the second problems. When the second problems were preceded by the execution of the better strategy, activations were found in LMFG (Left Middle Frontal Gyrus), LPreCG (Left Precentral Gyrus), LOFC (Left Orbitofrontal Cortex), and LIPL (Left Inferior Parietal Lobule) between 100 and 350 ms and between 850 and 1,250 ms.