CSCD 487/587 Human Computer Interface Winter 2013 Lecture 4 Human 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, d

4www.id-book.com 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

5www.id-book.com 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

6www.id-book.com Attention Selecting things to concentrate on at a point in time from 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?

7www.id-book.com Attention Information at the interface should be structured to capture users’ attention, Use perceptual boundaries (windows), Colour, reverse video, sound and flashing lights

8www.id-book.com Attention Information at the interface can be used to help or hinder our attention See next slides for examples ….

9www.id-book.com Activity: Find the price of a double room at the Holiday Inn in Bradley

10www.id-book.com Activity: Find the price for a double room at the Quality Inn in Columbia

11www.id-book.com Activity Tullis (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

12www.id-book.com 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 , 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 Attention 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 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 Attention 4. 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

17www.id-book.com Design Implications for Attention Make information prominant when it needs attending to Use techniques that make things stand out Color, Ordering, Spacing, underlining, Sequencing and animation Avoid cluttering interface with too much information Avoid using too much because the software allows it

18www.id-book.com An Example of Over-use of graphics

Describe this picture … What do you notice?

Another example

21www.id-book.com 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

22www.id-book.com Is color contrast good? Find Italian

23www.id-book.com Are borders and white space better? Find french

24www.id-book.com 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?

25www.id-book.com Which is Easiest to Read and Why? What is the time?

26www.id-book.com 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 !!!