Chapter+Five


 * Chapter 5:**

__Cognitive psychology (or Cognition)__: comprises those aspects of our mental life concerned with perception, reasoning, memory and attention, and language. · Cognitive psychology gave us __information processing__ which draws very strong parallels between functioning of the brain and computers. · Human information processing paradigm: o Simplifies people’s abilities into 3 blocks § Sensory input subsystem § Central information processing subsystem § Motor output subsystem · Very similar to main elements of computer · Fig. 5.1 pg. 100
 * 5.2: Cognitive psychology and HIP (human information processing)**
 * 5.3: A seven-stage model of activity**
 * Norman argues that we start with a **goal**, set **intentions** to achieve this goal, and then translated into a **sequence of actions** which we then **execute**
 * **Gulf of execution**: problem of how an individual translates intentions into action
 * **Gulf of evaluation**: converse and refers to how an individual understands, or evaluates the effects of actions and knows when his or her goals are satisfied
 * 5.4: Memory**
 * Working memory:
 * Short-term memory store holding material for up to 30 seconds and is very limited in size
 * Holding only 3-4 ‘chunks’ of information
 * Long-term memory:
 * Effectively the inverse of working memory
 * Capacity is unlimited
 * Last from a few minutes to a lifetime
 * Recall and recognition
 * Recall: individuals actively search their memories to retrieve a particular piece of information
 * Recognition: searching your memory and then deciding whether the piece of information matches what you have in your memory store
 * Recognition is easier and quicker than recall
 * 5.5: Attention**
 * Central to learning, perception, operating a machine, using a computer and so forth
 * Practice reduces the amount of attention required
 * Closely coupled with awareness
 * **Controlled processing:** makes heavy demands on attentional resources, is slow and limited in capacity, and involves consciously directing attention towards a task
 * **Automatic processing:** makes no demands on attentional resources, is fast, unaffected by capacity limitations, unavoidable and difficult to modify, and is not subject to conscious awareness
 * Vigilance: refers to detecting a rare event or a signal in a desert of inactivity or noise
 * 5.6: Visual perception**
 * Concerned with extracting meaning from the light falling on our eyes
 * Detecting colour, shapes and the edges of objects
 * 5.7 The Gestalt Laws of perception**
 * Proximity: objects appearing close together in space or time tend to be perceived together.
 * Continuity: perceive smooth, continuous patterns rather than disjoint, interrupted ones.
 * Part-whole relationships: the whole is greater than the sum of its parts
 * Similarity: similar figures tend to be grouped together
 * Closure: closed figures are perceived more easily than incomplete (or open) figures. This feature is so strong that we even supply missing information ourselves to make a figure easier to perceive
 * 5.8: Depth Perception:**
 * //4 key primary depth cues://
 * Retinal disparity: our eyes are approx. 7 cm apart; brain processes the difference and interprets it as distance information
 * Steropsis: different images of the world received by each eye are combined to produce a single 3d experience
 * Accommodation: we change the shape of the lens in our eyes in order to create a sharply focused image.
 * Convergence: over distances of 2-7 meters we move our eyes more and more inward to focus on an object at these distances.
 * Secondary depth cues:
 * Rely on only one eye
 * Light and shade
 * Linear perspective
 * Height in the horizontal plane
 * Motion parallax
 * Overlap
 * Relative size
 * Texture gradient
 * 5.11: mental models**
 * Mental model: cognitive representation of our understanding.
 * May have structure