The role of implicit perceptual-motor costs in the integration of information across graph and text.

Strategies used to gather visual information are typically viewed as depending solely on the value of information gained from each action. A different approach may be required when actions entail cognitive effort or deliberate control. Integration of information across a graph and text is a resource-intensive task in which decisions to switch between graph and text may take into account the resources required to plan or execute the switches. Participants viewed a graph and text depicting attributes of two fictitious products and were asked to select the preferred product. Graph and text were presented: (1) simultaneously, side by side; (2) sequentially, where the appearance of graph or text was triggered by a button press, or (3) sequentially, where the appearance of graph or text was triggered by a saccade, thus requiring cognitive effort, memory, or controlled processing to access regions out of immediate view. Switches between graph and text were rare during initial readings, consistent with prior observations of perceptual "switch costs." Switches became more frequent during re-inspections (80% of time). Switches were twice as frequent in the simultaneous condition than in either sequential condition (button press or saccade-contingent), showing the importance of perceptual availability. These results show that strategies used to gather information while reading a graph and text are not based solely on information value, but also on implicit costs of switching, such as effort level, working memory load, or demand on controlled processing. Taking implicit costs into account is important for a complete understanding of strategies used to gather visual information.