Visual Perception

Question 1

Gestalt Perception

Answer 1

• Human vision is biased to perceive structure
• Whole shapes, figures and objects

Gestalt
* German for “unified whole”
* Essence or shape of an entity’s complete form
* Pattern, configuration

Question 2

Gestalt Principles

Answer 2

• Gestalt principles are laws of human perception
• How we find order in what we see
• How we recognize groups, relationships and patterns
• How we see individual elements as a whole
• How we simplify complex images when we perceive objects

Question 3

Perception of Objects: Emergence

Answer 3

• “Seeing the big picture”
• Perceiving the whole
  without having to analyse
  the individual part

Question 4

Perception of Objects: Closure

Answer 4

• Seeing the complete shape even when only parts are visible
• The mind fills in the gaps

Question 5

Perception of Objects: Continuity

Answer 5

• Grouping elements that
  follow the same path
• Seeing a continuous shape even if partly occluded

Question 6

Perception of Groups: Proximity

Answer 6

• Objects that are closer
  together are perceived as a group

Question 7

Perception of Groups: Similarity

Answer 7

Objects that share visual
characteristics are
perceived as grouped

Question 8

Perception of Groups: Common Region

Answer 8

Objects that are within the same region are perceived as one group

• In many guidelines, this
  principle is called
  “Enclosure”

Question 9

Perception of Image Structure:
Figure/Ground

Answer 9

• To simplify an image, the brain separates foreground (“figure”)
  from background (“ground”)
• Important, as more attention is
  given to the foreground

Question 10

preattentive processing

Answer 10

Preattentive processing of visual information is performed
automatically on the entire visual field
* quickly, effortlessly and in parallel
* without focussing visual attention

Question 11

Pop-out features

Answer 11

• Pop-out features (also called out preattentive features) are visual properties that
  can be perceived without focussed attention

Question 12

Pop-out features for data visualisation

Answer 12

• Pop-out features help communicate
  information efficiently
• Some features pop out more than others
• Colour is stronger than shape
• Motion is effective
  (but can be annoying)

Question 13

Visualisation: Basics

Answer 13

In visualisation, we represent different types of data:

Categorical: Named labels (e.g., colors, types).

Ordinal: Ordered values (e.g., rankings).

Quantitative: Numeric values with measurable magnitude.

We use perceptual channels like position, size, color, brightness, and shape to visually represent this data.

Question 14

Visual Encoding: Colour Hue and Value

Answer 14

Value (lightness) is good for showing order, so it’s useful for ordinal data, but less effective for continuous variables. We perceive contrast better than exact values.

Colour (hue) is unordered, making it suitable for categorical (nominal) data.

Rainbow color scales are common but not ideal, as they can mislead or confuse interpretation.