Central to a cognitive perspective is the idea that individuals are active information processors, not passive recipients of environmental input. Cognitive theorists emphasize this type of active, top-down processing, meaning that prior expectations and cognitions play an important role in how incoming information is organized and handled. According to a cognitive view, the world of information that is available to a perceiver is not constrained by the stimuli available to the senses but rather by the abilities to process and deal with information from that world. The ways in which people process information can make order from disorder and sense from nonsense. The same processes, however, also can lead to losses of information and to distortions in memory. For this reason, cognitive theorists often gain insights into the nature of information processing by assessing misperceptions, inaccurate memories, use of heuristics, and selective attention and memory, because in those instances there may be incongruence between the environmental input and one’s concepts.