Adaptive Interface for Mobile Devices in User's Context

1. Week: 02 Human-Computer Interaction Waseem Iqbal Assistant Professor PhD-Scholar (Adaptive Interface for Mobile Devices in User’s Context)

2. Acknowlwdgement Dr. Ibrar Hussain(Assistant Professor / HEC Approved Supervisor) • PhD. in Computer Science Pervasive Computing Research Lab, Zhejiang University, China. Carried out 6 months collaborative research work with HCI & SE group at University of Colorado, Boulder, USA. Human Computer Interaction (Book) • 3rd Edition by Alan Dix

3. Attention Memory There are three types of memory function: Sensory memories (Sensor buffers) Short-term memory or working memory Long-term memory Rehearsal

4. Information is passed from sensory memory into short-term memory by attention, thereby filtering the stimuli to only those which are of interest at a given time. • We are able to focus our attention selectively, choosing to attend to one thing rather than another. • We can choose which stimuli to attend to, and this choice is governed to an extent by our arousal, our level of interest or need.

5. Sensory Memory • Buffers for stimuli received through senses • Iconic memory for visual stimuli. • Echoic memory for aural stimuli. • Haptic memory for tactile stimuli. • These memories are constantly overwritten by new information coming in on these channels. • Examples • “sparkler” trail from fireworks.

6. Short-term memory (STM) • Scratch-pad for temporary recall. • rapid access ~ 70ms. • rapid decay ~ 200ms. • limited capacity - 7± 2 chunks. • The successful formation of a chunk is known as closure.

7. Examples 212348278493202 0121 414 2626 HEC ATR ANU PTH ETR EET

8. Long-term memory (LTM) • If STM is our working memory, LTM is our main resource. • 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 semantic LTM derived from episodic LTM.

9. Long-term memory (cont.) • Semantic memory structure • provides access to information • represents relationships between bits of information • supports inference • Model: semantic network • inheritance – child nodes inherit properties of parent nodes • relationships between bits of information explicit • supports inference through inheritance

10. LTM - semantic network

11. Models of LTM - Frames • Information organized in data structures • Slots in structure instantiated with values for instance of data • Type–subtype relationships DOG Fixed legs: 4 Default diet: carniverous sound: bark Variable size: colour COLLIE Fixed breed of: DOG type: sheepdog Default size: 65 cm Variable colour

12. Models of LTM - Scripts • Model of stereotypical information required to interpret situation. • Script has elements that can be instantiated with values for context. • E.g., John took his dog to the surgery. After seeing the vet, he left.

13. Models of LTM - Production rules • A final type of knowledge representation which we hold in memory is the representation of procedural knowledge, our knowledge of how to do something. • 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

14. LTM - Storage of information • Rehearsal - Repeated exposure to a stimulus or rehearsal of piece of information, transfers information from STM to LTM. • Total time hypothesis - Amount learned was directly proportional to the amount of time spent learning. • Distribution of practice effect - Learning time is most effective if it is distributed over time.

15. LTM - Storage of information (Cont.) • Structure, meaning and familiarity • Information is easier to remember if it is meaningful. • A set of words is more difficult to remember if representing concepts than a set of words representing objects. E.g., • List A:Faith Age Cold Tenet Quiet Logic Idea Value Past Large • List B:Boat Tree Cat Child Rug Plate Church Gun Flame Head

16. LTM - Forgetting Decay- Information is lost gradually but very slowly. Interference -If we acquire new information it causes the loss of old information. - New information replaces old is known as retroactive interference. E.g., Replacing new telephone No with the old one. - Old information may interfere with the new is called proactive inhibition. E.g., Driving old home address instead of the new house. so may not forget at all memory is selective … … affected by emotion – can subconsciously `choose' to forget

17. LTM - Retrieval • Recall - Information is reproduced from memory can be assisted by cues, e.g., categories, imagery (visualize a scene). • Recognition -the presentation of the information provides the knowledge that the information has been seen before. It is the less complex cognitive activity than recall, since the information is provided as a cue/sign/indication.

18. Thinking Reasoning deduction, induction, abduction Problem solving

19. Thinking • Thinking is basically the way how information is processed and manipulated. • It is complex and separates human from other information-processing systems, both natural and artificial. E.g., animals and AI systems. • It requires different amount of knowledge. E.g., performing a subtraction calculation, understanding a newspaper headlines.

20. Reasoning • It is the process by which we use the knowledge we have to draw conclusions or infer something new about the domain of interest. • Different types of reasoning are: • Deductive Reasoning. • Inductive Reasoning. • Abductive Reasoning.

21. Deductive Reasoning • Deduction - derive logically necessary conclusion from given premises. e.g. If it is Friday then she will go to work It is Friday Therefore she will go to work. • Logical conclusion of the given premises, it does not necessarily have to correspond to our notion of truth. e.g. If it is raining then the ground is dry It is raining Therefore the ground is dry

22. Deduction (cont.) • When truth and logical validity clash … e.g. Some people are babies Some babies cry Inference/interpretation - Some people cry • Correct? • Invalid deduction since we are not told that all babies are people. It is therefore logically possible that the babies who cry are those who are not people. • Explanation for the above is that people bring their world knowledge into reasoning process.

23. Inductive Reasoning • Induction-is generalizing from cases we have seen to infer information about cases we have not seen. • e.g. all elephants we have seen have trunks therefore all elephants have trunks. • Unreliable: • In spite of its unreliability, induction is a useful process, which we use constantly in learning about our environment. • Humans not good at using negative evidence • e.g. Wason's cards.

24. 4 E 7 K Wason's cards • A common response to this is to check the E and the 4. However, this uses only positive evidence. In fact, to test the truth of the statement we need to check negative evidence: if we can find a card which has an odd number on one side and a vowel on the other we have disproved the statement. We must therefore check E and 7. If a card has a vowel on one side it has an even number on the other ?

25. Abductive reasoning • Abduction- It reasons from a fact to the action or state that caused it. • reasoning from event to cause • e.g. Sam drives fast when drunk. • If I see Sam driving fast, assume drunk. • this too is unreliable since there may be another reason why she is driving fast: she may have been called to an emergency. • If an event always follows an action, the user will infer that the event is caused by the action unless evidence to the contrary is made available. In fact, event and action are unrelated.

26. Problem solving • It is the process of finding solution to unfamiliar task, using the knowledge we have. • Several theories. • Gestalt - problem solving involves both reuse of knowledge and insight/perception. • Addresses productive problem solving (insight and restructuring of a problem) and reproductive problem solving (on previous knowledge). • Backed up their claims with experimental evidence. • Move away from behaviourism and led towards information processing theories.

27. Problem solving (cont.) Problem space theory - • Problem space comprises problem states, problem solving involves generating states using legal operators. • Heuristics may be employed to select operators. E.g. means-ends analysis. • Operates within human information processing system e.g. STM limits etc. • Largely applied to problem solving in well-defined areas e.g. puzzles rather than knowledge intensive areas.

28. Problem solving (cont.) • Analogy • analogical mapping: • novel problems in new domain? • use knowledge of similar problem from similar domain • analogical mapping difficult if domains are semantically different • Skill acquisition: • skilled activity characterized by chunking • lot of information is chunked to optimize STM • conceptual rather than superficial grouping of problems • information is structured more effectively

29. Errors and mental models 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 humans create mental models to explain behaviour. if wrong (different from actual system) errors can occur.

30. Emotion • Various theories of how emotion works • James-Lange: emotion is our interpretation of a physiological response to a stimuli. • Cannon: emotion is a psychological response to a stimuli. • Schacter-Singer: emotion is the result of our evaluation of our physiological responses, in the light of the whole situation we are in. • Emotion clearly involves both cognitive/mental and physical responses to stimuli.

31. Emotion (cont.) • The biological response to physical stimuli is called affect • Affect influences how we respond to situations • positive  creative problem solving • negative  narrow thinking “Negative affect can make it harder to do even easy tasks; positive affect can make it easier to do difficult tasks” (Donald Norman)

32. Emotion (cont.) • 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.

33. Individual differences • long term – Gender, physical and intellectual abilities • short term – effect of stress or fatigue • changing – age Ask yourself:will design decision exclude section of user population?

34. Psychology and the Design of Interactive System • Some direct applications • e.g. blue acuity/sharpness is poor blue should not be used for important detail • However, correct application generally requires understanding of context in psychology, and an understanding of particular experimental conditions.