Model-based Highlighting to Support Selective Reading on the Web

Model-based Highlighting to Support Selective Reading on

the Web

Ion Juvinaijuvina@andrew.cmu.edu

About... ... me Information Science @ UU.NL

Aknowledgements Herre van Oostendorp Eelco Herder Ellert van den Broek Vincent van der Linden Koen Buurman Poyan Karbor Brian Pauw Arnaud Lek Martijn Abbing Richard van Yperen

Contents Introduction Study “Individual differences” Cognitive model Study “Voice suggestions” Study “Graphical suggestions” Study “VIP” Conclusion and discussion

Introduction Navigation is a major part of user

experience on the web (Lazar, 2003) Web interfaces

Structure vs. content Revisits

Post valued recall Case: using the web by visually impaired

persons (VIP) via screen readers

Study “Individual differences” Objective:

Identify determinants of performance and satisfaction in web-assisted tasks

Activities Morrison, Pirolli and Card (2001)

Types of activities users perform on the Web.

2188 usable responses. Example:

I accessed Netscape's financial site to check mycredit card balance and how long it would take topay it off. I'm now MUCH more fiscally aware of myspending habits and am trying to pay off my balancemore actively.

Tasks

Hypothetical factors Domain expertise Working memory capacity Episodic memory Cognitive style Spatial ability Age Gender

Navigation metrics

Results

Results (cont’d)

Results (cont’d)

Cognitive models SNIF-ACT CoLiDeS MESA Value and limitations:

Information scent Common Too narrowly defined

Semantics prevail over syntax Static background knowledge Common user prevails over individual

differences

CoLiDeS+

Models vs. data

Study “Voice suggestions”

Study “Graphical suggestions”

Study “Graphical suggestions” (cont’d)

Study “VIP” Manipulation

Screen switched off Highlighting by increasing reading priority Suggestions generated on-the-fly

No look ahead Results:

Common mechanism Spatial ability – task performance

Weak suggestion mechanism Position: 5 -> 4 Breaks of coherence

Conclusions Support for selective reading is:

Needed Possible Not easy

Empirical research and cognitive modeling could help

Discussion points Ecological validity vs. accuracy ? Scalability of cognitive models ? Ontologies vs. semantic spaces ? Goals known in advance ? Static goal representations ?