Visual Perception Basics

Using knowledge of human perception

to design effective visuals

Zachary del Rosario (zdelrosario@olin.edu)

1

Warmup!

2

Same Data, Two Visualizations

Which of the two graphs on the next slide best helps you answer the question:

​

“What trends are there in the data?”

3

Q: Which Best Shows Trends in the Data?

A

B

4

Same Data, Two Visualizations

Which of the two graphs on the next slide best helps you answer the question:

​

“Due to budget cuts, data collection halted---when?”

5

Q: Which Best Shows Missing Data?

A

B

6

Goals for Today

1. Learn the visual hierarchy
2. Practice identifying rungs on the visual hierarchy
3. Use the visual hierarchy for productive criticism

7

The Visual Hierarchy

8

The Visual Hierarchy

Idea: Different methods for showing data give people a more or less accurate impression of value

9

The Visual Hierarchy

(Most accurate)

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

(Least accurate)

10

The Visual Hierarchy

Example: The same data and variables,

six different views

11

1. Common Scale

12

2. Non-aligned Scale

13

3. Length

14

4. Angle

15

5. Area

16

6. Color Saturation

17

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

18

Q: What Rung Is Used for CO2 Concentration?

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

19

Q: What Rung Is Used for CO2 Concentration?

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

20

Q: What Rung Is Used for CO2 Concentration?

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

21

Q: What Rung Is Used for CO2 Concentration?

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

22

Q: Which Best Shows Trends in CO2 Concentration? Why?

A

B

23

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

​

Should we always follow this principle?

24

Q: Which Best Shows Missing Data?

A

B

25

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

​

Should we always follow this principle?

​

No, but it’s a useful guideline

26

Practice

Let’s talk about some graphs

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Name That Rung!

Describe which rung on the Visual Hierarchy is used to show each variable

28

Which Rung?

GDP/Capita: ?

Continent: ?

Life Exp: ?

Population: ?

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

29

Which Rung?

GDP/Capita: Common scale

Continent: Common scale*

Life Exp: Color saturation

Population: Area

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

30

Which Rung?

GDP/Capita: ?

Continent: ?

Life Exp: ?

Population: ?

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

31

Which Rung?

GDP/Capita: Common scale

Continent: Color hue*

Life Exp: Common scale

Population: Area

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

32

Q: Which Better Shows Trends in the Data?

A

B

33

Name That Rung!

One more pair

34

Which Rung?

GDP/Capita: ?

Country: ?

Life Exp: ?

Year: ?

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

35

Which Rung?

GDP/Capita: Common scale

Country: Color hue

Life Exp: Color saturation

Year: Common scale

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

36

Which Rung?

GDP/Capita: ?

Country: ?

Life Exp: ?

Year: ?

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

37

Which Rung?

GDP/Capita: Color saturation

Country: Color hue

Life Exp: Common scale

Year: Common scale

Remember:

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

38

Q: Which Better Shows Trends in the Data?

A

B

39

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your “most important variables”

​

You have to decide which are most important

​

E.g. What’s your punchline?

40

Closing

41

The Visual Hierarchy

(Most accurate)

• Position along a common scale
• Position along non-aligned scales
• Length
• Angle; Slope
• Area
• Volume; Density; Color saturation
• Color hue

(Least accurate)

42

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

• Guideline, not a law!
• Need to decide which are most important

43