The Human HCI 101 PDF

The Human HCI 101 Topic 01 - Vision 02 - Reading 03 - Hearing 04 - Touch 05 - Movement 06 - Memory 07 - Thinking 08 - Emotion The human 1 Information input and output  visual, auditory, haptic, movement 2 Information stored in memory  sensory, short...

The Human HCI 101 Topic 01 - Vision 02 - Reading 03 - Hearing 04 - Touch 05 - Movement 06 - Memory 07 - Thinking 08 - Emotion The human 1 Information input and output  visual, auditory, haptic, movement 2 Information stored in memory  sensory, short-term, long-term 3InInformation processed and applied  reasoning, problem solving, skill, 4 error influences human capabilities Emotion 5 Each person is different 01 - Vision Two stages in vision 1 physical reception of stimulus 2 processing and interpretation of stimulus  The Eye Physical reception  Interpreting the Size and depth signal  visual angle indicates how much of view object occupies  visual acuity is ability to perceive detail  familiar objects perceived as constant size  cues like overlapping help perception of size and depth  Interpreting the Brightness Colour signal  Interpreting the signal The visual system compensates for:  movement  changes in luminance Optical Illusions 02 - Reading Several stages:  visual pattern perceived  decoded using internal representation of language  interpreted using knowledge of syntax, semantics, Reading pragmaticsinvolves saccades and fixations Perception occurs during fixations Word shape is important to recognition Negative contrast improves reading from computer screen 03 - Hearing Provides information about  environment: distances, directions, objects etc. Physical apparatus:  outer ear  middle ear  inner ear Sound  Pitch  Loudness  timbre 04 - Touch Provides important feedback about environment. May be key sense for someone who is visually impaired.received via receptors in the skin: Stimulus  Thermoreceptors  Heat and cold  Nociceptors  Pain  Mechanoreceptors  Pressure heat and cold Some areas more sensitive than others e.g. Kinethesis fingers. - awareness of body position 05 - Movement Time taken to respond to stimulus:  reaction time + movement time Movement time dependent on age, fitness Reaction etc. time - dependent on stimulus type: Visual  Auditory  Pain Increasing reaction time decreases accuracy in the unskilled operator but not in the skilled operator. 05 - Movement Fitts' Law describes the time taken to hit a screen target:  Mt = a + b log2(D/S + 1) where: a and b are empirically determined constants Mt is movement time D is Distance S is Size of target 06 - Memory There are three types of memory function: Sensory memories Short-term memory or working memory Long-term memory Selection of stimuli governed by level of arousal. Sensory memory Buffers for stimuli received through senses  iconic memory  echoic memory  haptic memory Short-term (STM) memory Scratch-pad for temporary recall  rapid access ~ 70ms  rapid decay ~ 200ms  limited capacity - 7± 2 chunks Long-term (LTM) memory Repository for all our knowledge  slow access ~ 1/10 second  slow decay, if any  huge or unlimited capacity Two types  episodic – serial memory of events  semantic – structured memory of facts, concepts, skills LTM - semantic network Models Frames of LTM -  Information organized in data structures  Slots in structure instantiated with values for instance of data  Type–subtype relationships DOG COLLIE Fixed Fixed legs: 4 breed of: DOG type: sheepdog Default diet: carniverous Default sound: bark size: 65 cm Variable Variable size: colour colour Models Scripts of LTM - Model of stereotypical information required to interpret situation Script has elements that can be instantiated with values for context Models rules of LTM - Production Representation of procedural knowledge. Condition/action rules if condition is matched then use rule to determine action. IF dog is wagging tail THEN pat dog IF dog is growling THEN run away LTM - information Storage of  rehearsal  total time hypothesis  distribution of practice effect  structure, meaning and familiarity LTM - Forgetting  decay  interference LTM - retrieval  recall  recognition 07 - Thinking 1 Reasoning 2 Problem solving Deductive Reasoning  Deduction - derive logically necessary conclusion from given premises.  Logical conclusion not necessarily true: Inductive Reasoning  Induction: generalize from cases seen to cases unseen  Unreliable: can only prove false not true  Humans not good at using negative evidence e.g. Wason's cards. Wason's cards Abductive reasoning  Reasoning from event to cause  Unreliable Problem solving  Process of finding solution to unfamiliar task using knowledge.  Several theories. Problem solving Problem space theory  problem space comprises problem states  problem solving involves generating states using legal operators  heuristics may be employed to select operators  operates within human information processing system  largely applied to problem solving in well-defined areas Errors models and mental Types of error  slips right intention, but failed to do it right causes: poor physical skill, inattention etc. change to aspect of skilled behaviour can cause slip  mistakes wrong intention cause: incorrect understanding 08 - Emotion Various theories of how emotion works 1 James-Lange: emotion is our interpretation of a physiological response to a stimuli 2 Cannon: emotion is a psychological response to a stimuli 3 Schacter-Singer: emotion is the result of our evaluation of our physiological responses, in the light of the whole situation we are in Emotion Implications for interface design  stress will increase the difficulty of problem solving  relaxed users will be more forgiving of shortcomings in design  aesthetically pleasing and rewarding interfaces will increase positive affect Individual differences  long term  short term  changing THANK YOU HCI