The Value of Information Visualization - Information Visualization: Human-Centered Issues and Perspectives - page 6

the questions? In this case, already challenging questions become practically
impossible.
2.1 Cognitive Benefits
While the states example illustrates that visualizations can help people under-
stand data better, how do visuals facilitate this process? The core of the benefits
provided by visuals seems to hinge upon their acting as a frame of reference or
as a temporary storage area for human cognitive processes. Visuals augment hu-
man memory to provide a larger working set for thinking and analysis and thus
become external cognition aids. Consider the process of multiplying two long in-
tegers in your head versus then having a pencil and paper available. The visual
representations of the numbers on paper acts as a memory aid while performing
the series of multiplication operations.
Performing a multiplication requires the processing of symbolic data, which
is arguably different than the processing of visual features and shapes. In “Ab-
stract Planning and Perceptual Chunks: Elements of Expertise in Geometry” [8],
Koedinger and Anderson show that experts in geometry effectively use their vi-
sion to infer geometrical properties (parallelism, connectivity, relative positions)
on diagrams; they solve simple problems quickly and accurately, several of mag-
nitude faster than if they had to apply symbolic inference rules.
Larkin and Simon, in their landmark paper “Why a diagram is (sometimes)
worth 10,000 words” [10], discuss how graphical visualization can support more
ecient task performance by allowing substitution of rapid perceptual inferences
for dicult logical inferences and by reducing the search for information required
for task completion. They do note that text can be better than graphics for
certain tasks, however.
Don Norman provides many illustrative examples where visuals can greatly
assist task performance and eciency [15]. He argues that it is vital to match the
representation used in a visualization to the task it is addressing. The examples
he cites show how judicious visuals can aid information access and computation.
Earlier, we noted how the definition of visualization from Card, Mackinlay
and Shneiderman [2] focused on the use of visuals to “amplify cognition.” Fol-
lowing that definition, the authors listed a number of key ways that the visuals
can amplify cognition:
- Increasing memory and processing resources available
- Reducing search for information
- Enhancing the recognition of patterns
- Enabling perceptual inference operations
- Using perceptual attention mechanisms for monitoring
- Encoding info in a manipulable medium
2.2 Perceptual Support
Most lectures on Information Visualization argue about theoretical properties of
the visual system or more broadly to the perception abilities of humans. Rational
arguments rely on information theory [21] and psychological findings.