Table 1 Mechanical Turk user study analysis

Training

1

1

Is the highlighted cluster mostly positive or mostly negative?

Clusters

N/A

Training

1

2

What is the height of the tree?

N/A

N/A

Timed

1

3

Which of the highlighted elements has the highest value?

Leaves

Score

0.380

4.578

5

4.695

E-01

Timed

1

4

Is the highlighted cluster mostly positive or mostly negative?

Clusters

Score

0.661

14.650

5

1.197

E-02

∗

Timed

1

5

What is the height of the tree?

N/A

Error

3.083

23.278

5

2.987

E-04

∗∗∗

Training

2

6

Which of the highlighted elements is furthest away from the root?

Leaves

N/A

Training

2

7

Which of the highlighted elements are siblings?

Leaves

N/A

Timed

2

8

Which of the highlighted elements is furthest away from the root?

Leaves

Score

0.605

63.540

5

2.250

E-12

∗∗∗

Timed

2

9

Which of the highlighted elements is furthest away from the root?

Clusters

Score

0.732

14.705

5

1.170

E-02

∗

Timed

2

10

Which of the highlighted elements are siblings?

Clusters

Score

0.864

21.662

5

6.070

E-04

∗∗∗

Training

3

11

Which two of the highlighted elements are more closely clustered?

Clusters

N/A

Training

3

12

How many visually distinct clusters do you see in this visualization?

N/A

N/A

Timed

3

13

Which two of the highlighted elements are more closely clustered?

Siblings

Score

0.738

29.499

5

1.850

E-05

∗∗∗

Timed

3

14

Which two of the highlighted elements are more closely clustered?

Leaves

Score

0.275

12.775

5

2.558

E-02

∗

Timed

3

15

Which two of the highlighted elements are more closely clustered?

Clusters

Score

0.352

9.539

5

8.941

E-02

·

Timed

3

16

Which of the highlighted elements is least similar to its neighbors?

Clusters

Score

0.283

13.726

5

1.745

E-02

∗

Timed

3

17

How many visually distinct clusters do you see in this visualization?

N/A

Value

8.794

31.138

5

8.796

E-06

∗∗∗