Memory evolved to supply useful, timely information to the organism's decision-making systems. Therefore, decision rules, multiple memory systems, and the search engines that link them should have coevolved to mesh in a coadapted, functionally interlocking way. This adaptationist perspective suggested the scope hypothesis: When a generalization is retrieved from semantic memory, episodic memories that are inconsistent with it should be retrieved in tandem to place boundary conditions on the scope of the generalization. Using a priming paradigm and a decision task involving person memory, the authors tested and confirmed this hypothesis. The results support the view that priming is an evolved adaptation. They further show that dissociations between memory systems are not-and should not be-absolute: Independence exists for some tasks but not others.Memory is a gift of nature, the ability of living organisms to retain and to utilize acquired information or knowledge. . . . Owners of biological memory systems are capable of behaving more appropriately at a later time because of their experiences at an earlier time, a feat not possible for organisms without memory. (Tulving, 1995a, p. 751) If there is one proposition on which all psychologists seem to agree, it is that memory is useful. Memory allows organisms to adjust their behavior on the basis of information they acquire ontogenetically, through their experiences with the world.This connection between personal experience, memory, and behavior implies a close relationship between learning and memory: "Memory in biological systems always entails learning (the acquisition of information) and . . . learning implies retention (memory) of such information" (Tulving, 1995a, p. 751). Recognizing this, psychologists have long exploited learning paradigms to study the properties of memory (e.g., by list learning to probe free recall, cued recall, and recognition).The same connection also implies a close relationship between decision rules 1 and memory. An organism cannot behave "more appropriately"-that is, more adaptively-at a later time because of experiences at an earlier time unless it is equipped with rules that use ontogenetically acquired information to make decisions. Indeed, memory systems must have evolved their structure in response to the informational needs of the decision rules guiding behavior. This is because memory properties that have no impact on an organism's decisions will not be visible to-and hence will not be shaped by-selection. Moreover, because decision rules often differ in what information they require, different sets of decision rules may activate different retrieval processes or search engines and may access different memory systems or sets of memory systems. Without engines that can search for and retrieve the right information, supplying it to the right decision rule at the right time, an organ designed to store ontogenetically acquired information-that is, a memory system-would be a pointless appendage. Hence, adaptive behavior over tim...