decisive workshop introduction

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Sources of bias when working with visualisations David Peebles University of Huddersfield November 8, 2014 David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 1 / 16

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Page 1: DECISIVe workshop introduction

Sources of bias when working with visualisations

David Peebles

University of Huddersfield

November 8, 2014

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 1 / 16

Page 2: DECISIVe workshop introduction

Where’s the ‘cognitive’?

Using visualisations prime example of‘embodied’ cognition (Wilson, 2002).

Situated in real-worldenvironment. Inherently involvesperception/action.

Time pressured. Underpressure of real-time interactionwith environment.

Exploits task environment toreduce cognitive workload byholding, representing, andmanipulating information.Knowledge in world combineswith knowledge in head.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 2 / 16

Page 3: DECISIVe workshop introduction

Where’s the ‘cognitive’?

Using visualisations prime example of‘embodied’ cognition (Wilson, 2002).

Situated in real-worldenvironment. Inherently involvesperception/action.

Time pressured. Underpressure of real-time interactionwith environment.

Exploits task environment toreduce cognitive workload byholding, representing, andmanipulating information.Knowledge in world combineswith knowledge in head.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 2 / 16

Page 4: DECISIVe workshop introduction

Where’s the ‘cognitive’?

Using visualisations prime example of‘embodied’ cognition (Wilson, 2002).

Situated in real-worldenvironment. Inherently involvesperception/action.

Time pressured. Underpressure of real-time interactionwith environment.

Exploits task environment toreduce cognitive workload byholding, representing, andmanipulating information.Knowledge in world combineswith knowledge in head.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 2 / 16

Page 5: DECISIVe workshop introduction

Where’s the ‘cognitive’?

Using visualisations prime example of‘embodied’ cognition (Wilson, 2002).

Situated in real-worldenvironment. Inherently involvesperception/action.

Time pressured. Underpressure of real-time interactionwith environment.

Exploits task environment toreduce cognitive workload byholding, representing, andmanipulating information.Knowledge in world combineswith knowledge in head.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 2 / 16

Page 6: DECISIVe workshop introduction

The embodied cognition-task-artefact triad

Embodied

CognitionTask

Artefact

Interactive

Behaviour

Interactive behaviour:

Emerges from dynamic interaction of goal-directed, task-drivencognition/perception/action with designed task environment.A complex combination of bottom-up stimulus driven and top-downgoal and knowledge driven processes.

Makes little sense to consider and investigate cognition in isolation.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 3 / 16

Page 7: DECISIVe workshop introduction

Sources of bias when working with visualisations

Bias. A systematic preference for aparticular pattern of behaviour in atask environment.

Question: How are preferences (andinterpretations) created/shaped bythe embodied cognition-task-artefacttriad?

Four sources of bias:

Computational affordances

Emergent/salient features

Gestalt principles of perceptualorganisation

Adaptive behaviour

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 4 / 16

Page 8: DECISIVe workshop introduction

Sources of bias when working with visualisations

Bias. A systematic preference for aparticular pattern of behaviour in atask environment.

Question: How are preferences (andinterpretations) created/shaped bythe embodied cognition-task-artefacttriad?

Four sources of bias:

Computational affordances

Emergent/salient features

Gestalt principles of perceptualorganisation

Adaptive behaviour

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 4 / 16

Page 9: DECISIVe workshop introduction

Sources of bias when working with visualisations

Bias. A systematic preference for aparticular pattern of behaviour in atask environment.

Question: How are preferences (andinterpretations) created/shaped bythe embodied cognition-task-artefacttriad?

Four sources of bias:

Computational affordances

Emergent/salient features

Gestalt principles of perceptualorganisation

Adaptive behaviour

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 4 / 16

Page 10: DECISIVe workshop introduction

Computational affordances (Peebles & Cheng, 2003)

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Jan FebMar AprMayJun Jul AugSep Oct NovDec

Am

ount P

rodu

ced

Month

Amount of Silver and Gold Produced (in tonnes)by ‘Precious Metals Plc.’ in 1996

Silver

Gold

Informationally equivalent

Computationally inequivalent.

Require different procedures.

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0 1 2 3 4 5 6 7 8 9 10

Gold

Silver

Amount of Silver and Gold Produced (in tonnes)by ‘Precious Metals Plc.’ in 1996

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

“When gold is 4, what is thevalue of silver?

“Which two months have thesame values of silver and gold?

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 5 / 16

Page 11: DECISIVe workshop introduction

Emergent/salient features

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 6 / 16

Page 12: DECISIVe workshop introduction

Emergent features (Peebles, 2008)

Tasks: local (1 feature) and global (all features) comparison.

Accuracy and latency of comparison judgements affected by:

Representation used.Value being compared.Emergent features created by arrangements of values.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 7 / 16

Page 13: DECISIVe workshop introduction

Emergent features affect distance perception

(a) Transport = 1.91 (b) Transport = 2.14

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 8 / 16

Page 14: DECISIVe workshop introduction

Gestalt principles (Ali & Peebles, 2013)

Laws of perceptual organisation (e.g., proximity, similarity, continuity,connectedness, common fate) affect grouping of graphical elements.

Low High

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Percent Error as a function of Experience and Time of Day

Pe

rce

nt

Err

or

Experience

Time of Day

Day

Night

Low High

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60

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90

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Percent Error as a function of Experience and Time of Day

Pe

rce

nt

Err

or

Experience

Time of Day

Day

Night

Line: Novices focus primarily on legend variable (connectedness andsimilarity).

Bar: Novices’ attention balanced between legend and x-axis variables.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 9 / 16

Page 15: DECISIVe workshop introduction

Using emergent features and Gestalt principles

AA AB

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Response Time as a function of Task and Stimulus Type

Re

sp

on

se

Tim

e

Task

Stimulus Type

Words

Pictures

(a) “Crossover” interaction

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90

100

Percent Error as a function of Experience and Time of Day

Pe

rce

nt

Err

or

ExperienceLow High

Time of Day

Day

Night

(b) “Colour-match” graph

(a) Experts learn emergent features for rapid pattern recognition.

(b) Knowledge of Gestalt principles can be used to design more effectiverepresentations (Ali & Peebles, 2013).

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 10 / 16

Page 16: DECISIVe workshop introduction

Basic elements of visualisation behaviour

Cognitive processes:

Goal setting and monitoring, initiate visual search, retrieval from LTM,generating inferences, etc.

Perceptual processes.

Judgement of length, direction, area, position on common scale(Cleveland & McGill, 1984).Visual comparisons of length, colour, shape, quantity.

Physical actions:

Eye movement saccades and fixations, mouse clicks and cursormovements, finger taps and pinches etc.Interface manipulations: Selection/highlighting with mouse; dragging,realigning, rotating, deleting; zooming in and out

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 11 / 16

Page 17: DECISIVe workshop introduction

Basic elements of visualisation behaviour

Cognitive processes:

Goal setting and monitoring, initiate visual search, retrieval from LTM,generating inferences, etc.

Perceptual processes.

Judgement of length, direction, area, position on common scale(Cleveland & McGill, 1984).Visual comparisons of length, colour, shape, quantity.

Physical actions:

Eye movement saccades and fixations, mouse clicks and cursormovements, finger taps and pinches etc.Interface manipulations: Selection/highlighting with mouse; dragging,realigning, rotating, deleting; zooming in and out

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 11 / 16

Page 18: DECISIVe workshop introduction

Basic elements of visualisation behaviour

Cognitive processes:

Goal setting and monitoring, initiate visual search, retrieval from LTM,generating inferences, etc.

Perceptual processes.

Judgement of length, direction, area, position on common scale(Cleveland & McGill, 1984).Visual comparisons of length, colour, shape, quantity.

Physical actions:

Eye movement saccades and fixations, mouse clicks and cursormovements, finger taps and pinches etc.Interface manipulations: Selection/highlighting with mouse; dragging,realigning, rotating, deleting; zooming in and out

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 11 / 16

Page 19: DECISIVe workshop introduction

Interactive routines

Basic cognitive, perceptual and motor operators combined intointeractive routines that take between 0.3 to 1 second to execute:

Direct attention to object and encode features/location.

Move mouse cursor to graphical object and click on it (seeCPM-GOMS model below; Gray & Boehm-Davis, 2000).

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 12 / 16

Page 20: DECISIVe workshop introduction

Unit tasks and strategy selection

Unit tasks: Combinations ofinteractive routines that performsubtasks.

Typical execution time: between 3sand 30s.

Select and visually mark subsetof data.

Locate variable value(s)according to some criterion(e.g., max, min, median etc.).

Strategies: Sequences of unit tasks.

Attend & click object

Look for 'Done' button

Click on 'Done' button

Encode object features & seek next object

Blended location retrieved,attend to location

Attend & click object

Encode object features & request retrieval

Relocate object & seek next object

Relocation

Presentation

Yes No

Current phase?

Unattended object?

Unattended object?NoYes

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 13 / 16

Page 21: DECISIVe workshop introduction

Unit tasks and strategy selection

Unit tasks: Combinations ofinteractive routines that performsubtasks.

Typical execution time: between 3sand 30s.

Select and visually mark subsetof data.

Locate variable value(s)according to some criterion(e.g., max, min, median etc.).

Strategies: Sequences of unit tasks.

Attend & click object

Look for 'Done' button

Click on 'Done' button

Encode object features & seek next object

Blended location retrieved,attend to location

Attend & click object

Encode object features & request retrieval

Relocate object & seek next object

Relocation

Presentation

Yes No

Current phase?

Unattended object?

Unattended object?NoYes

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 13 / 16

Page 22: DECISIVe workshop introduction

Adaptive behaviour

Interactive routine changesreduce interaction cost &optimise control system resourceallocation. Milliseconds matter(Gray & Boehm-Davis, 2000)

Ballard et al. (1995) increasedinformation access cost from eyemovement to head movement –users shifted from display basedaccess to memory retrieval.

Attend & click object

Look for 'Done' button

Click on 'Done' button

Encode object features & seek next object

Blended location retrieved,attend to location

Attend & click object

Encode object features & request retrieval

Relocate object & seek next object

Relocation

Presentation

Yes No

Current phase?

Unattended object?

Unattended object?NoYes

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 14 / 16

Page 23: DECISIVe workshop introduction

Adaptive behaviour

Interactive routine changesreduce interaction cost &optimise control system resourceallocation. Milliseconds matter(Gray & Boehm-Davis, 2000)

Ballard et al. (1995) increasedinformation access cost from eyemovement to head movement –users shifted from display basedaccess to memory retrieval.

Attend & click object

Look for 'Done' button

Click on 'Done' button

Encode object features & seek next object

Blended location retrieved,attend to location

Attend & click object

Encode object features & request retrieval

Relocate object & seek next object

Relocation

Presentation

Yes No

Current phase?

Unattended object?

Unattended object?NoYes

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 14 / 16

Page 24: DECISIVe workshop introduction

Adaptation as a source of bias

Adoption and adaptation determined by:

Cost structure of the task environment (i.e., how quick/easy is it toexecute the task).

The representational efficiency of the visualisation.

History of success with the strategy.

Adaptation typically beneath conscious awareness and deliberatecontrol.

Do users always adapt to an optimal interaction?

Not necessarily – only when local (interactive routine level) optimumcoincides with global task level optimum (Fu & Gray, 2004).

Suboptimal interaction and interpretation may result from strategyselection pressures resulting from unconscious choices made at theembodiment level.

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 15 / 16

Page 25: DECISIVe workshop introduction

Summary

Interpretation of data graphics can be shaped/biased bynumber of factors:

Visual and computational properties of the representation.Adaptive behaviour of the user seeking to minimise effort.

Research on simpler data graphics must be extended to:

Larger and more complex data sets.Broader class of visualisations.Cover the increasing variety of interactions and manipulations that arebeing developed.

Vital for design of most appropriate representations/taskenvironments for different users and tasks and to reduce error.

Important role for cognitive science theories and methods inthis research (e.g., computational cognitive modelling)

David Peebles (University of Huddersfield) Biases and visualisations November 8, 2014 16 / 16