In two experiments, subjects learned an unfamiliar campus environment, either by studying a map or by navigating. During acquisition, the subjects had one of two spatial goals: to learn the layout of the building (survey goal) or to learn the fastest routes between locations (route goal). Spatial memory was tested with several tasks, some assessing survey perspective processing and some assessing route perspective processing. Results indicate multiple influences on the representation of spatial perspective. Learning condition influenced performance. Individuals studying maps gave more accurate responses to some survey perspective tasks, whereas individuals navigating gave more accurate responses to some route perspective tasks. Spatial goals also influenced performance. Having a route goal enhanced performance on route perspective tasks; having a survey goal enhanced performance on survey perspective tasks. These findings are discussed in the context of research indicating flexibility when processing spatial perspective. Individuals can use spatial information from different perspectives, often doing so in a goal-directed manner.Negotiations ofour environment, such as walking across campus, riding a bike home, or driving to a new destination, require complex spatial information. This information can come from different sources-including exploration, maps, and verbal descriptions-and can be isomorphic, but the sources differ in ways that may impact how we mentally represent the information. Primary differences between spatial information sources fall into two categories: the symbolic nature of the information and the spatial perspective imparted, either route or survey. We will concentrate on the latter. The purpose of the present research is to examine the influence of perspective-based goals (survey and route) on spatial memory from different information sources (maps and navigation). These effects will be examined, using a number of different spatial tasks.Maps and navigation impart different types of spatial information, most notably the spatial perspective. Perspective generally reflects the viewpoint taken on the environment, either within (route perspective) or above (survey perspective). Other types of knowledge gained through maps and navigation contribute to the overall sense of each perspective, including the reference system for locating new landmarks, whether the orientation is stable or changing, and the amount of information available at a given time. Exploration of an environment provides route information, the characteristics of which include a within-environment viewpoint, a viewer-centered

Generative encoding contexts promote activation of multiple retrieval routes and have been shown to enhance free-recall rates of individuals without mental retardation. The present extension to individuals with mental retardation involved a comparison of two encoding conditions: (a) fade-in, initially presenting pictures out of focus then slowly fading them into focus, and (b) fade-out, presenting pictures clearly then slowly blurring them. Results indicated that free-recall rates were greater for the fade-in items for the individuals with mental retardation and CA-matched comparisons, but not for the MA-matched group. These findings demonstrate the utility of a generative encoding context that does not involve verbal instruction for individuals with and without mental retardation.

The ability of individuals with mental retardation to focus on task-relevant elements of complex visual arrays and increase visual-search efficiency was investigated. Initial assessments of visual-search efficiency were conducted to identify pairs of features for the form and size dimensions for which each participant demonstrated serial search. Subsequently, color was added as a defining feature that could guide search to a subset of the elements in the array. Results indicated that all of the individuals with mental retardation were able to limit attention to the task-relevant items on the guided search task, thus greatly reducing overall target identification times. Results show that individuals with mental retardation can demonstrate sophisticated visual selective attention skills when visual arrays are structured appropriately.

Abilities of individuals with and without mental retardation to search for and detect salient changes to naturalistic scenes were investigated using the flicker paradigm. Located in areas of central or marginal interest, changes involved an object's color, shape, or presence. Individuals with mental retardation required more time to detect changes of all types, and the magnitude of the group difference was more pronounced for marginal-interest changes. Supplemental eye-tracking data from 6 participants suggested that the basis of this effect was that individuals with mental retardation tended to maintain gaze in the region of central interest for longer periods of time prior to sampling the other areas of the scene. Implications for intelligence-related differences in visual attention are discussed.