CHAPTER5

toc =Chapter 5 and 15: Understanding Individual Users=

Important Elements of Cognitive Psychology • Memory (sensory, working and long-term) • Recall and recognition • Attention • Perception • Gestalt processing • Representation • Mental models • Action and persuasion
 * Cognitive Psychology** comprises those aspects of our mental life concerned with perception, reasoning memory, attention and language.

Memory
• Complex • Active • Contextual • Constructive/Additive

Human memory is described as having two components: Working memory and long term memory.

Working memory
>
 * Retention: hold material for up to 30 seconds.
 * Size: hold only 3 or 4 chunks of information.
 * Rehearsal: to mention the contents of working memory it needs to be rehearsed. Rehearsal involves mentally refreshing the contents of working memory.
 * Limited capacity: Working memory can store a small amount of visual information ( visuo-spatial sketchpad-minds eye) and a small amount of verbal information( in the articulatory loop-inner voice).
 * Chunking: It is a technique that we as humans use to group items in to more meaningful unit s.-helps memorizing
 * Manuals: writing down instructions is effective for extending our memories.

Long Term Memory

 * Its the opposite of working memory.
 * Unlimited capacity: the storage space is endless.
 * Filtered: Most working memory is dumped i.e. we only remember the important or significant stuff.
 * Relational: We remember things in context and connection-whether the connections make sense or not.
 * Multi modal and complex: Trying to remember the smell of a flower, voice of a friend etc.

Recall and Recognition
>
 * Recall is the process whereby individuals actively search their memories to retrieve a particular piece of information.
 * Recognition involves searching your memory and then deciding whether the piece of information matches what you have in your memory store.
 * From chap 15: it's much easier to recognize something than recalling it. Good recognition design tips are picklist, thumbnailas

Forgetting
> > > > > > > > >
 * From chap 15
 * Accessbility vs. availability: sometimes we forget because we aren't able to retrieve infomation that's stored or sometimes we forget simply because the information was not stored in the first place.
 * For working memory:
 * //Decay theory//: memory simply fades with time. If the working memory is not refreshed within 30 seconds, it will decay and be lost.
 * //Displacement theory//: also due to limited storage, contents in working memory can be easily overwritten by new materials.
 * Long Term Memory: retroactive, proactive and compromised networks.
 * Interference theory: forgeting is strongly influenced by what we have done before or after learning.
 * Retroactive Interference (RI): new learning interferes with earlier learning.
 * Proactive Interference (PI): earlier learning interferes with new learning. e.g. it's hard to learn functions in newer versions of the same system.
 * Retrieval Failure Theory: memory can't be retrieved because we haven't used the correct retrieval cues. e.g. tip of the tongue phenomenon.

MAC Formating Palette Example:
> > >
 * Figure 5-4 on p. 106
 * The palette has been designed to use recognition than recall.
 * Direct manipulation: clicking on items rather than having to memorize the name of fonts
 * Extensive use of chunking: The palette has been organized in to four chunks (font, alignment and spacing, borders and shading, document) --> which are logical groups or chunks of function.
 * The use of meaningful associations: B for bold etc.

Attention
It is defined as focusing of mental resources at or on a particular task or object. > >
 * Attention can not only be **focused** but also be **divided** between several tasks up to a certain **limit**.
 * Practices reduced the amount of attention required, enabling us to perform other tasks concurently.
 * Attention and awareness are closely linked.
 * It is essential to human activity-a lot of human error can be traced to faulty attention.

Attention can be considered in terms of Controlled and Automatic Processing: >
 * **Controlled processing:** high demand on attentional resources, slow and limited in capacity, focused and thorough.
 * **Automatic Processing:** makes little or no demand on attentional resources, it is fact and not affected by capacity limitations, allows for multitasking, almost subconscious, vague.

>
 * Factors Affecting Attention**
 * Chapter 15
 * //Mental/Physical Workload//: Stress and Frustration.
 * //Distraction//: Competing things to attend to.
 * //Time Pressures//

> > > >
 * Designing for Attention**
 * From Chapter 15
 * //Attracting and holding attention//: to do so without distracting users away from main task, or overwhelming the user with more information they can reasonably understand or respond to. e.g. email alerts in inbox
 * //Vigilance//: is a term applied to the execution of a task wherein an individual is required to monitor an instrument or situation for a signal. It refers to detecting a rare event or signal in a desert of inactivity or noise.
 * //Mental Workload//: how busy is the user
 * //Visual Search//: the designer needs to divert users' visual attention into main target
 * //Signal Detection Theory//: designing for situation in which there are two different, non-overlapping states (signal and noise) that can't be easily discriminated. e.g. Compute users need to know when the documents are printed, train drivers need to spot a stop light from far away.

Perception
Perception is immediate or intuitive recognition or appreciation, as of moral, psychological, or aesthetic qualities. It is concerned with extracting meaning( recognition and understanding) > >
 * Factors affecting perception**
 * Expectations of a situation
 * Culture
 * Motivation
 * State of sensory arousals
 * Past Experiences
 * Consistency is assumed - can lead to illusion p. 111

**The Gestalt Laws of Perception**
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 * **Promixity**: Close things are grouped i.e. the objects that appear to be closer are perceived to be together in a group. for e.g. a row or columns or a song.
 * **Continuity**: We tend to perceive smooth continuos patterns rather than disjoint, interrupted ones.
 * **Part/Whole relationships.** We understand parts as a part of the system. The whole is greater than the sum of its parts.
 * **Similarity**: similar things are seen as together.
 * **Closure:** Closed figures are perceived more easily than incomplete /open ones so we fill in case the information is missing we fill in gaps ourselves to make the figure easier to perceive.

Depth Perception
Primary Cues: retinal disparity, stereopsis, accomodation, convergence. Secondary Cues (Monocular Depth Cues - relying on only one eye): Perception of Depth on flat visual displays:
 * **Light and shade:** An object with its attendant shadow improves the sense of depth. e.g. a cup.
 * **Linear Perspective:** use of linear perspectives give some idea of depth.
 * **Relative height and size:**Height in horizontal plane-distant objects appear higher than nearer objects. Smaller objects are usually seen as being further away.
 * **Motion Parallax**: When looking out a train or a car window, objects which are nearer such as a pole pass quickly in contrast to a distant building which passes slowly.
 * **Overlap**: An object which hides the sight of another is understood to be nearer.
 * **Texture**: textures surfaces look closer, irregularities appear to be more distant.

Mental Model
Mental model refers to to a cognitive representation of our understanding and it influences our long term memory to focus attention on important things.

Design problem: > >
 * Designer expects users to operate system a certain way --> an intended mental model
 * User's mental model is developed through several interactions with the system
 * This results in an unclear system image and the user forms a different mental model.


 * Norman** has made the following observations on the design of mental models:
 * Incomplete
 * Poorly tested
 * unstable-people forget details
 * unreliable
 * vague boundaries-similar devices and operations get confused with one another
 * superstitious or illogical

Leveraging Mental Models
• Consistency and Coherence • Design for Error and Feedback • Preparation for cognitive dissonance and frustration • Re-education and persuasion (attention issue)

Examples: New input/output devices
• New devices and tools challenge pre-existing notions of interaction - require readjustment on the part of user • Examples? • Fun might be the best way to educate?

Chapter 15: More Concepts: