CSCD 487/587Human Computer Interface

Winter 2013

Lecture 4Human Cognition

Overview Move on to discussing HUMANS and how they

process information How they see, hear and touch their surroundings

We consider what humans are good and bad at and show how this knowledge can be used to assist design of technologies

– That both extend human capabilities and compensate for their weaknesses

We also look at some influential cognitive-based conceptual frameworks that have been developed for explaining the way humans interact with computers

Cognition Cognitive

What does it mean?

1. The mental act or process by which knowledge is acquired, including perception, intuition, and reasoning

2. The knowledge that results from such an act or process

Collins English Dictionary,

http://dictionary.reference.com/cite.html?qh=cognition&ia=ced

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Understanding Human Abilities

Interacting with technology is cognitive Need to take into account cognitive processes

involved and cognitive limitations of human users

Knowledge about what users can and cannot be expected to do with regards to technology

Identifies and explains the nature and causes of problems users encounter

Know theories, modeling tools that can lead to design of better interactive products

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Cognitive processes

So, what are the main cognitive processes? Attention

Perception and recognition

Memory

Learning

Reading, speaking and listening

Problem-solving, planning, reasoning/decision-making

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Attention Selecting things to concentrate on at a point

in timefrom the mass of stimuli around us Allows us to to focus on information that is

relevant to what we are doing Involves audio and/or visual senses Having clear goals helps us focus our

attention and enables us to be selective in terms of the mass of competing stimuli

Example: Long flight … what do you focus on when you land?

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Attention

Information at the interface should be structured to capture users’ attention,

Use perceptual boundaries (windows),

Colour,

reverse video,

sound and flashing lights

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Attention

Information at the interface can be used to help or hinder our attentionSee next slides for examples ….

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Activity: Find the price of a double room at the Holiday Inn in Bradley

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Activity: Find the price for a double room at the Quality Inn in Columbia

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ActivityTullis (1987) found that two screens produced quite different results

1st screen - took an average of 5.5 seconds to search

2nd screen - took 3.2 seconds to search Why, since both displays have the same density of information (31%)?Spacing

1st screen• Information is bunched up together,

making it hard to search

2nd screen• Characters are grouped into vertical

categories of information making it easier

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Multitasking and Attention

Is it possible to perform multiple tasks without one or more of them being detrimentally affected?

Think about how we all work these days. Constantly checking email, facebook and

watching videos …

Ophir et al (2009) compared heavy vs light multi-taskers

Heavy - more prone to being distracted than those who infrequently multitask

Heavy multi-taskers are easily distracted and find it difficult to filter irrelevant information

Laws of Attentionhttp://www.visualexpert.com/Resources/

lawsofattention.html

Human Factors expert, Dr. Green discusses some laws of Attention

Attention is a complex phenomenon that has been extensively studied for many years. In general there are six laws ...

1. People have a fixed amount that must be allocated according to need

Analogy, attention is like a bucket of water. People draw upon it as needed, but every dipper full

and every teaspoon full leaves less for other purposes.

2. Attention is selective People attend some things to the exclusion of others. This follows directly from Law #1, as there is too little

mental resource to attend everything.

Laws of Attention

3. Consciousness Requires Attention The cocktail party phenomenon illustrates that humans

have a single stream of conscious attention which is difficult or impossible to divide

Possible to be aware at different levels.

In the cocktail party, for example, people may be dimly aware of the vague background buzz or may not be aware at all

However, humans seem capable of consciously attending to only one information source at a time, at least meaning Consciousness is a unitary stream

Laws of Attention4. Attention does not require consciousness People are only partially conscious of their attention

Some attention may be allocated without awareness to a task This occurs in behaviors that have become automatic through overlearning, learning of a skill well past the point of mastery

Much of normal driving occurs automatically and outside of awareness

Drivers have little or no conscious awareness of steering, using the foot pedals, etc

This can go so far as the common phenomenon of "highway hypnosis," where a motorist travels for an extended period with no conscious awareness or memory of having driven the car

Laws of Attention

5. All tasks require some degree of attention, although the required amount may be small

It is not surprising that operating the in-car navigation device or reading a billboard can distract a driver and cause an accident

Research suggests that a task as apparently undemanding as listening to the radio can also cause distraction and increase accident likelihood

Even the most seemingly effortless tasks, like walking and maintaining an upright posture consume and require attention. For example, distraction is a major cause of accidents during staircase descent

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Design Implications for AttentionMake information prominant when it needs attending toUse techniques that make things stand out

Color,

Ordering,

Spacing, underlining,

Sequencing and animationAvoid cluttering interface with too much informationAvoid using too much because the software allows it

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An Example of Over-use of graphics

Our Situation

State the bad news

Be clear, don’t try to obscure thesituation

Describe this picture …What do you notice?

Another example

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Perception

How information is acquired from world and transformed into experiences .. via 5 senses

• Eyes, Nose, Ears, Mouth and Touch

Obvious implication is to design representations that are readily perceivable, e.g.

• Text should be legible• Icons should be easy to distinguish

and read

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Is color contrast good? Find Italian

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Are borders and white space better? Find french

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Activity

Weller (2004) found people took less time to locate items for information that was grouped

Using a border (2nd screen) compared with using color contrast (1st screen)

Some argue that too much white space on web pages is detrimental to search

Makes it hard to find information Do you agree?

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Which is Easiest to Read and Why?

What is the time?

What is the time?

What is the time?

What is the time?

What is the time?

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Perception Design Implications

Icons should enable users to readily distinguish their meaning Bordering and spacing are effective visual ways of grouping information Sounds should be audible and distinguishable Speech output should enable users to distinguish between the set of spoken words Text should be legible and distinguishable from the background Tactile feedback should allow users to recognize and distinguish different meanings

Summary

Human cognition is extremely important for designers of human technology

We need to know how people's brains operate on the physical level

– Seeing, hearing and overall functioning

Plus, how they make decisions and process information

This will help design fun, useful products

The End New assignment up !!!