# Presentation: 037071

## How does the spatial structure of  

- How does the spatial structure of
- visualizations affect reasoning?

## Spatial structure of visualizations

- Relations
- Proximity
- Direction
- Elements
- Iconic: resemblance
- Figurative: “White House,” scales of justice
- Abstract: lines, arrows, boxes, blobs

## Interpreting graphs

- Bars: contain & separate

- Lines: connect

- Zacks & Tversky

## Interpreting and producing graphs

- Bars: discrete comparisons

- Lines: trends

## Arrows (asymmetric lines)

- Heiser & Tversky

## Arrows convert structural to causal reasoning 

- Arrows convert structural to causal reasoning

## Arrows have many meanings

- How to pass a law

- Labeling
- Movement
- Temporal sequence
- Causal sequence

## Representing space, time, & agents

*Production*, *preference*,and *performance *reveal
- Mental representations
- Graphic devices
- Cognitive design principles
- Space/time/agent displays have many uses

- Kessell & Tversky

## Design visualization: track friends during day

-  74% make tables
- Time horizontal
-  Agents entries

**Notes:**
Students were asked to produce a visualization to keep track of where 4 friends are at different times of day.  Most produced tables that regarded time and space categorically, not dimensionally.  Most put time and space as axes and agents as entries.

## Different tables for different queries or inferences?

- Dots vs. lines (agents)
- Inferences, preferences, and queries
- Predictions:
- Comparisons: Dots
- Sequences: Lines

**Notes:**
We designed two interfaces, one a pure table with agents as entries, one where agents’ movements were connected by paths
We developed a dozen kinds of questions that participants answered from the interfaces

## Participants used either line or dot interface

- Inferences
- Preferences
- Query times

**Notes:**
These are the two interfaces.  Each agent has a different color.  Participants used one interface on half the trials and the other on the other half.  At the end we ask about preferences for one interface or the other.  The lines may facilitate some questions, but they add clutter, perhaps making other questions harder to answer

## Drawing inferences

**Notes:**
Information is often visualized for exploration, to find patterns.  Do the interfaces with lines make salient different patterns from the interface without lines?  To assess this, we ask two more group of students to make as many inferences as they can see from each interface.  We will score code the inferences as we coded the queries, by focus.  We will analyze both the order of making inferences and the number of kinds of inferences from each interface.

## People
Place 
Time
Place & time
People, place, and time
Sequence
Intersections
Miscellaneous

- Place
- Time
- Place & time
- People, place, and time
- Sequence
- Intersections
- Miscellaneous

- Queries: retrieval times

**Notes:**
We asked 8 kinds of questions, varying whether the focus of the question was agent, place, or time, or combinations of these.  We measure the time to answer as well as whether the response is correct or not.  Some examples of questions follow.  We expect that some of the questions will be easier to answer with the lines and some harder (take longer and lead to more errors)

## Dots vs. Lines

- Dots: for comparisons
- More inferences
- Preferred
- Faster retrieval times
- Lines: for sequences
- More inferences
- Preferred
- No advantage in retrieval times

## Next steps

Scaling up
3-D layering
Other lines, blobs, & arrows
Narratives
Explanations

- Scaling up
- 3-D layering
- Other lines, blobs, & arrows
- Narratives
- Explanations

## Story about a line

## People: “Sammy was alone all the time”
Place: “Only 3 people visited dorm”
Time: “People were in 2 places in the evening”
Place & Time: “The dorm had 1 person at noon” 
People, Place, & Time: “In the morning, Sammy was at the gym
Sequence: “David went from gym to bookstore to library”
Intersection: “At some point, Alex and Justin were together

- Place: “Only 3 people visited dorm”
- Time: “People were in 2 places in the evening”
- Place & Time: “The dorm had 1 person at noon”
- People, Place, & Time: “In the morning, Sammy was at the gym
- Sequence: “David went from gym to bookstore to library”
- Intersection: “At some point, Alex and Justin were together

- Examples of Queries

**Notes:**
On each trial, students see the interface and one question.  They answer the question “true” or “false” as quickly as possible by pressing one of two keys.  We are still collecting data so we do not yet have clear answers.  Early analyses indicate that that the lines facilitate some questions but not others.