Six experiments addressed the combinatorial influence of multiple related primes in naming, lexical decision and relatedness judgment performance. Primes either converged on a single semantic representation (e.g., LION-STRIPES-TIGER) or diverged onto distinct semantic representations (e.g., KIDNEY-PIANO-ORGAN). The facilitatory influence of 2 related primes was well predicted by the sum of the influences from the single-related-prime conditions (a) for both convergent and divergent primes, (b) in lexical-decision and naming, (c) across varying prime-target stimulus onset asynchronies, and (d) under target-degradation conditions that increased the priming effects. The relatedness-judgment task yielded an additive pattern of priming for convergent prime conditions; however, an underadditive pattern of priming was found for divergent prime conditions. Discussion focuses on the role of attentional systems that modulate the type of information used to perform a given task.