The “Post-‐PC” Era • 1960s (Mainframes): 100s of users per computer • 1970s (Minicomputers): 10s of users per computer • 1980s (PCs): 1 user per computer • 1990s-‐2000s (Mobile): 10s of computers per user • The Future (Ubicomp): 100s, 1000s of computers per user
Challenges of Ubicomp Design: • Appropriate physical interac=on • Applica=on themes & requirements • Theories/Methods for design & eval
Interac=on • Natural & implicit input – Which mode to use when? • Mul=scale and distributed output – Which informa=on to put where? • Integra=on of physical and virtual – How best to link the two?
Models of Interac=on • Ac=vity Theory: goals and ac=ons are ﬂuid, tools shape behavior • Situated Ac=on: behavior is improvisa=onal, context is important • Distributed Cogni=on: knowledge is in the world, especially ar=facts
What is Informa=on? Informa=on is anything that can change person’s knowledge Belkin, 1978
Two kinds of knowledge Personal Experience Second-‐Hand Knowledge We do not believe everything other people tell us. People make judgments about how useful informa=on is to their par=cular needs, ac=vely construct meaning, form judgments about the relevance of the informa=on. Patrick Wilson
Human Informa=on Behavior the study of a variety of interac=ons between : • people (individuals, groups, professions) • various forms of “informa=on” or knowledge • Encountering with systems, services, networks, technology ... • The context of use
Informa=on Seeking Behavior What people do in response to goals (inten=ons) which require informa=on support How people seek informa=on by interac=ng with various informa=on systems How people communicate informa=on with people
Informa(on Behavior Informa(on Seeking Behavior Informa(on Search Behavior T.D. Wilson
More deﬁni=ons Process in which humans purposefully engage in order to change their state of knowledge (Marchionini, 1995) A conscious eﬀort to acquire informa=on in response to a need or gap in your knowledge (Case, 2002) …ﬁing informa=on in with what one already knows and extending this knowledge to create new perspec=ves (Kuhlthau, 2004)
Game Theory Cooperate Defect Cooperate 3,3 0,5 Defect 5,0 1,1 The Prisoner’s dilemma ?
Repeated Game Grim Trigger • Cooperate un=l a rival deviates • Once a devia=on occurs, play non-‐ coopera=vely for the rest of the game Tit for Tat • Cooperate if your rival cooperated in the most recent period • Cheat if your rival cheated in the most recent period
ICD Challenges: Moral Hazard One side lacking informa=on about the other’s ac=ons Adverse Selec=on High-‐quality traders being less likely to trade than low-‐quality traders, because the other side cannot dis=nguish them
Adverse Selec=on Can lead to breakdown of the high-‐quality market – Fewer high-‐quality sellers leads to buyers being willing to quote a lower price – Lower price dissuades high-‐quality sellers even further buyers’ lack of credible informa=on about product
Moral Hazard One side lacking informa=on about the other’s ac=ons – eg, if there are no postal receipts, only the seller knows if he shipped the item. Would hold as long as seller’s incen=ve to ship is less than seller’s incen=ve to not ship
Reputa=on systems can poten=ally reduce both moral hazard and adverse selec=on eﬀects.