Attention in direct and indirect memory tasks with short- and long-term probes

In two experiments, college students verified the answers to addition problems as their primary task while simultaneously viewing a word or nonword. The degree of attention allocated to the verbal stimulus varied depending on the difficulty of the problem and the instructions given. After each problem, a test probe assessed either a direct test of recognition memory or an indirect test of repetition priming in lexical decision at lags of 0, 1, or 8 intervening trials. The degree of attention at encoding and lag strongly affected recognition sensitivity (d'), but only lag affected recognition latencies. The repetition-priming effect neither declined with lag nor varied with the degree of attention. The degree of attention at encoding thus affects direct and indirect test performance differentially, a finding consistent with the distinction between explicit and implicit systems of long-term memory.