Lecture 4

Question 1

What does it take to notice a choice option? And when does this fail?

Answer 1

Just giving something a bright colour or making it shiny is not enough in certain circumstances.

• E.g., a parrot wearing a red santa hat doesn’t stand out on a picture filled with red parrots wearing bright colours.

If everything is screaming for your attention, nothing actually catches your attention.

• E.g., times square

Question 2

What do we need to perceive?

Answer 2

We need our senses: touch, sight, taste, smell and sound.

You can argue that there are more senses, for example perception, where are you in space and the sensation on your lips.

Question 3

Sensation

Answer 3

The processing of the information that comes from our sensory system.

Senses just sense.

Question 4

Perception

Answer 4

The organisation, identification, and interpretation of sensory information in order to represent and understand the environment.

This is the brain process.

Question 5

What is our main sense?

Answer 5

Our visual sense

Question 6

Are perception and sensation interchangeable terms?

Answer 6

No

Question 7

Principles of perception

Answer 7

• Constancy (standvastigheid)
• Grouping
• Contrast effect

Question 8

Constancy principle

Answer 8

The tendency to perceive an object you are familiar with as having a constant shape, size, and brightness despite the stimuli changes that occur.

• Related to the status quo bias; we like things the way they are.
• E.g., a door looks like the same door from different angles.

The principle of things being constant works in two ways (the sensory information is the same):

• If the input is different we still perceive it as one object (this happens most of the time).
• It creates an illusion. This is because we know how certain things work (e.g., shadows) and we overcorrect.

Question 9

Grouping

Answer 9

From gestalt psychology

The tendency to perceive patterns in and between objects based on certain rules (regular, orderly, simple etc). We like to group things together.

• In heuristics this is called a cluster illusion.

Proximity, similarity and enclosure.

Question 10

Proximity

Answer 10

Grouping

We tend to see things that are in close proximity of each other as a bigger whole.

Question 11

Similarity

Answer 11

Grouping

We tend to see things that are similar as one thing

• E.g., in the example you tend to see four rows and not four columns.

Question 12

Enclosure

Answer 12

Grouping

Focuses specifically on the use of borders or containing shapes. It focuses on how we perceive objects enclosed in a common area.

Elements enclosed within a boundary tend to be perceived as a figure against the surrounding ground.

Question 13

Contrast effect

Answer 13

Object are not perceived alone.

In the context of other objects and their features the perception changes.

Question 14

Salience

Answer 14

The level at which an object stands out from other objects based on one or more features.

Question 15

Visibility

Answer 15

The state of on object being able to be perceived per se.

Question 16

Are salience and visibility interchangeable terms?

Answer 16

No.

Question 17

What do models of attention concern themselves with?

Answer 17

Salience

Question 18

How can saliency differ?

Answer 18

Saliency can be big and small.

When you are searching for a particular object or a person, the saliency is very small.

If you are searching for a particular person with a santa suit on in a street filled with people wearing santa suits that person’s salience is very small.

Question 19

Visual search research

Answer 19

If you get a single visual search task, it doesn’t matter how many distractors there are, the green letter T stands out, it’s quite salient.

But as soon as the features of the distractors are played with, e.g., by adding green X’s, it becomes a harder task to find the green letter T. This is because the green T doesn’t stand out as clearly, it is less salient.

This is where the focus of attention comes in.

Question 20

Models of attention

Answer 20

• Feature Integration Theory
• Guided Search Theory

Question 21

What do models of attention deal with?

Answer 21

They deal with salience.

They answer questions like:

• How does salience arise when it’s small?
• How do specific combinations of features of an object get made salient and get selected for further processing?

Question 22

Anne Treisman’s Feature Integration Theory

Answer 22

At some point attention grabs into perception. Typically you first perceive separate features (e.g., colour, orientation).

If a feature in the visual field is already salient enough, then there is no attentional switching needed. But if the unique thing that you’re searching for is in a combination map (a feature integration map), then you need your attentional process.

Attention = A top-down active search light moving over a ‘combined features’ map.

Question 23

Wolfe’s Guided Search Theory

Answer 23

Similar to the theory of Anne Treisman, but more parallel.

The image you get in your visual field is split up into multiple components. He also talks about a combination feature map,. He says that every feature gives some activation on the location in the vision field, and at some point there is a net activation, which is the highest level of saliency if you had to pick out certain objects. In some cases, there is not a clear peak, he argues that in those cases attention sets the gaze for different features differently (either colour or orientation etc.). He argues that the attention is somewhere on a lower level.

Attention = An amplifier of important feature maps that lead to a clear salient combination over others.

Question 24

What do Treisman and Wolfe have in common?

Answer 24

In both cases they describe the attentional process as something where your brain decides to search for something. This is a top-down process, whereas something that pops up automatically is harder to perceive.

Question 25

Treisman (Feature Integration Theory) vs Wolfe (Guided Search Theory) on selection of salient objects

Answer 25

Treisman: attentional selection happens at the level of a map of combined features.

Wolfe: attentional selection happens by prioritizing certain feature maps and thus changing the map of combined features.

Question 26

Treisman (Feature Integration Theory) vs Wolfe (Guided Search Theory) on attention

Answer 26

Treisman: a top-down active search light moving over a ‘combined features’ map’.

Wolfe: an amplifier of important feature maps that lead to a clear salient combination over others.

Question 27

What are top-down and bottom-up processes similar to?

Answer 27

System 2 and system 1.

Question 28

How automatic is attentional selection?

Answer 28

Task performance can be disrupted by automatic processes in attentional selection (e.g., attentional capture).

Question 29

Attentional capture

Answer 29

= Task performance being changed by bottom-up grabbing of attention.

= It is when something that is very salient, but task irrelevant, can break your attention and make you a bit slower.

• E.g., if you need to say whether a green candy cane is up or down, and all of a sudden there is also a red candy cane, this will delay your reaction because it disrupts the automatic processes.

Attentional capture can also be measured with eye movements.

The stronger the distractor the stronger the diversion.

Question 30

Article by Wang et al. 2013 on attentional capture

Answer 30

The salience of a distractor in attentional capture is not only determined by visual properties, but also by perceived value.

Take home message: the perceived positive or negative value of a stimulus can act as a distractor in attentional capture just as any other salient feature.

If you first train someone on a red colour, meaning that they get either a monetary reward (positive value) or a shock (negative value), then red becomes quite important. The colour red then also results attentional capture.

So it’s not just visual things that capture your attention, but also something that is perceived to be salient. This is because you’ve learned to get money or to pay. Having to pay works better/is more salient than getting money because paying is a more innate human fear than money. It is also related to loss aversion, you tend to stay away from losing money; negative sums, and shocks.

Question 31

Mind-set in attention

Answer 31

Not only bottom-up or value driven salience, but also mind-set / task focussing determines standing out.

Based on perceptual set factors such as context your perception of a stimulus can be different.

Question 32

Example of rabbit or duck

Answer 32

Do you see a duck or a rabbit? Probably, your brain will want you to see the image of the animal you first heard or whatever image is more familiar to you. By asking a guided question (Do you see a mammal? Do you see a bird?) you can influence someone’s expectations and you see what the person wants you to see.

Question 33

Perceptual set theory

Answer 33

The psychological fact is that you determine how you perceive your environment.

Sometimes seeing is believing, but the perceptual set theory teaches us that believing is also seeing.

Expectations are a factor in your perceptual set. If you expect to see a rabbit, you’ll see a rabbit, and not the duck.

Context is another factor in your perceptual set, if the duck/rabbit was surrounded with easter eggs you would think rabbit right away.

Saliency can be something you decide, or is caused by sensory input.

Question 34

Example of healthy snack car

Answer 34

They did an experiment where they offered people a healthy snack option at Utrecht Central, they tested and designed the whole thing. They put a cart on Central station and watched if people would go to their snack cart rather than a rivals snack cart. They sold 5,5 snack on average from 2-7 pm on a random afternoon. It has to do with the context. They were at the stairs outside of the hallway of the station. People make their food decision ín the hallway. So, they offered something that was quite attention grabbing but in the context of people already having made a food choice and having a snack already, people’s mind sets were not on snacking more. They missed their opportunity.

This is an example of the effects of context.

Question 35

What if attention is too strong?

Answer 35

Based on the perceptual set theory your perception of a stimulus can become different.

What about the effect of focussing on a task? => Attentional selection can also be too strong.

This is called inattentional blindness (sometimes attentional blindness or change blindness) .

Question 36

Inattentional blindness

Answer 36

When you are focussing so much on one task that you don’t notice anything else.

Question 37

Example of a two choice nudge where one option is a recipe for a healthy but not so tasty dish, and the other option is a recipe for an unhealthy but tasty dish. They manipulated how many times the recipe was downloaded (social proof). The healthy option was downloaded quit more often.

Would this work from an attention and perception perspective?

Answer 37

No, because the amount of downloads is not salient enough, it doesn’t stand out at all. They confirmed this with eye tracking.

Question 38

An example is an experiment they did during covid. They did a social distancing study where they tried to maintain the social distance between young people on campus. Why did young people not keep their distance? Because they didn’t feel that at risk. So, they tried to elicit more empathy for people who are unrelated to them. So to keep their distance from others, not for themselves but for others. They had a campaign made with a movie clip of 30s that was showing a movie all day long for a whole week. The screen was salient, playing audio, not too long. Then they would turn the screen off for a control week. They placed cameras to calculate the distance between people.

The effect was only around 20 cm.

What went wrong?

Answer 38

Students didn’t pay attention because their mindset was somewhere else, people were busy going to their lecture hall or meeting. A completely different mindset.

Question 39

What should you be aware of when designing a nudge?

Answer 39

Be aware not only of dual systems and heuristics.

Also be aware of:

• Perception and its principles
• Attention and how this can lead to both ‘blind perception’ or ‘attention grabbing’.

In other words: don’t be nudge experts, be nudge magicians!