Global precedence in attention and decision.

This article examines the order in which people recognize and respond to different levels of structure within a visual display. Certain previous experiments have been interpreted as showing that information about global characteristics of an array is extracted by the visual system before information about local characteristics. Results from a task in which the observer must attend to both global and local information demonstrate that local information has a large influence on reaction time even when information at the global level is sufficient to determine the response. This finding implies that local information becomes available to decision processes with a time course similar to that of global information. Effects previously attributed to the order in which different levels of structure are recognized may result from differential ease of directing attention to these different levels and selecting responses based on them.