Age-related resistance to speed pressure in lexical decision: high error costs and a conservative response gating

Age-related slowing in choice reaction time tasks is traditionally interpreted as either a consequence of cognitive decline or a strategic shift toward conservative decision policies. The present experiment investigated this phenomenon by combining a lexical decision task with a speed-accuracy trade-off (SAT) manipulation and electromyographic (EMG) recordings of response-related muscle activity. Beyond the classic global slowing, the performance of older adults was characterized by a marked resistance to speed pressure. Even when explicitly instructed to prioritize speed over accuracy, older participants maintained more conservative operating criteria compared to younger controls, avoiding the more error-prone regions of the performance space. This error-aversion was observed together with maladaptive post-error processing under speed pressure, higher temporal costs for the online correction of covert (partial) errors, and an enhanced baseline susceptibility to provisional incorrect response activations. These findings suggest that age-related slowing, and the resistance to speed pressure in particular, reflects a functional adaptation to a dual constraint: disproportionately high costs for both overt and covert errors, particularly when performing under speed pressure, and a noisier decision-to-motor transition.