Table Of ContentBuilding Experiments in PsychoPy
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Building Experiments in
PsychoPy
Jonathan Peirce
& Michael MacAskill
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SAGE Publications Ltd
1 Oliver’s Yard
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London EC1Y 1SP
SAGE Publications Inc.
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© Jonathan Peirce and Michael MacAskill 2018
First published 2018
Original creation of PyschoPy software Jonathan Peirce © all screenshots
taken directly from PyschoPy, created and maintained by Jonathan Peirce,
notable contributors: Jeremy Gray, Sol Simpson, Mike MacAskill, Jonas
Lindelшv, Richard Hцchenberger, Hiroyuki Sogo, Yaroslav Halchenko,
Erik Kastman, William Hogman, Ilixa Ltd., Gary Strangman. PsychoPy is
developed almost entirely by volunteers, please see a full list of
contributors at Ohloh.net
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Apart from any fair dealing for the purposes of research or private study,
or criticism or review, as permitted under the Copyright, Designs and
Patents Act, 1988, this publication may be reproduced, stored or
transmitted in any form, or by any means, only with the prior permission
in writing of the publishers, or in the case of reprographic reproduction, in
accordance with the terms of licences issued by the Copyright Licensing
Agency. Enquiries concerning reproduction outside those terms should be
sent to the publishers.
Library of Congress Control Number: 2017958160
British Library Cataloguing in Publication data
A catalogue record for this book is available from the British Library
ISBN 978-1-4739-9138-5
ISBN 978-1-4739-9139-2 (pbk)
Editor: Becky Taylor
Editorial assistant: Katie Rabot
Production editor: Imogen Roome
Copyeditor: Neville Hankins
Proofreader: Neil Dowden
Marketing manager: Lucia Sweet
Cover design: Wendy Scott
Typeset by: C&M Digitals (P) Ltd, Chennai, India
Printed in the UK
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Contents
Acknowledgments
How to use your book
1 Introduction
1.1 Creating experiments
1.2 Building versus coding
1.3 Pros and cons of open-source software
1.4 Understanding your computer
1.5 What is PsychoPy?
1.6 Getting started
1.7 Going further
1.8 Conventions of this book
I For the beginner
2 Building your first experiment
2.1 The Builder interface
2.2 Building the Stroop task
2.3 Define your conditions
2.4 Defining the trial structure
2.5 Adding a loop to repeat trials
2.6 Varying your stimuli on each trial
2.7 Add some instructions
2.8 Add a thank-you slide
2.9 Changing your info dialog
2.10 Analyze your data
3 Using images: a study into face perception
3.1 Accuracy versus reaction time
3.2 Testing face recognition
3.3 Image sizes in different units
3.4 Comparing inverted and correctly oriented faces
3.5 Additional options for images
3.6 Using Opacity
3.7 Using Masks
3.8 Present a movie instead of an image
4 Timing and brief stimuli: Posner cueing
4.1 Presenting brief stimuli precisely
4.2 Posner cueing
5 Creating dynamic stimuli (revealing text and moving stimuli)
5.1 What does dynamic mean and why is it useful?
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5.2 Inserting code into parameters
5.3 Example 1: Revealing text gradually
5.4 Example 2: Spinning, expanding images
5.5 Example 3: Change colors through the rainbow
5.6 Example 4: Make a heart that has a pulse
5.7 Going further
6 Providing feedback: simple Code Components
6.1 Providing feedback
6.2 Updating the feedback color
6.3 Reporting the reaction time
6.4 Ideas for useful code snippets
6.5 Reporting performance over the last five trials
7 Ratings: measure the ‘Big 5’ personality constructs
7.1 Instruments for the measurement of personality
7.2 Categories, Likert or continuous ratings
7.3 Controlling when the Rating is finalized
7.4 What to store
7.5 Finishing your task and scoring the data
8 Randomization, blocks and counterbalancing: a bilingual
Stroop task
8.1 Blocking trials
8.2 The bilingual Stroop task
8.3 Build a blocked version of the Stroop task
9 Using the mouse for input: creating a visual search task
9.1 Getting spatial responses
9.2 Visual search
9.3 Implementing the task
9.4 Introducing the Mouse Component
9.5 Control stimulus visibility from a conditions file
9.6 Control stimulus positions using code
9.7 Responding to mouse clicks spatially
9.8 Selectively skipping a routine
9.9 Making smooth trial transitions
9.10 Pointing rather than clicking
II For the professional
10 Implementing research designs with randomization
10.1 How can we assign subjects to conditions or groups?
10.2 Understanding loop ordering options
10.3 Summary
11 Coordinates and color spaces
11.1 Coordinate systems
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11.2 Color spaces
11.3 Phase of textures
12 Understanding your computer timing issues
12.1 Understanding screen refresh rates
12.2 Testing your stimulus timing
12.3 Timing by screen refresh
12.4 Images and timing
12.5 Response-time precision
13 Monitors and Monitor Center
13.1 Computer display technology
13.2 Monitor Center
13.3 Monitor calibration
13.4 Spatial calibration
13.5 Gamma correction
13.6 Color calibration
13.7 Procedure
14 Debugging your experiment
14.1 Common mistakes
14.2 Common error and warning messages and what they
mean
14.3 How to debug an experiment
14.4 Writing a better query to the forum
15 Pro tips, tricks and lesser-known features
15.1 Adding a README file to your experiment
15.2 Expand or shrink the Flow and Routine
15.3 Copying and pasting Routines and Components
15.4 Online repositories for sharing your experiments
15.5 Using variables from the dialog box in your
experiment
15.6 Controlling names of your data files and folders
15.7 Running in windowed mode
15.8 Recreating your data files
15.9 Skipping a part of your experiment
15.10 Turn tips back on
III For the specialist
16 Psychophysics, stimuli and staircases
16.1 Gratings and Gabors
16.2 Smooth-edged masks (Gaussian and raised cosine)
16.3 Using images as masks
16.4 Element arrays
16.5 Random Dot Kinematograms
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16.6 Staircase and QUEST procedures
17 Building an fMRI study
17.1 Detecting trigger pulses
17.2 Non-slip timing
17.3 How to calibrate a monitor for fmri
18 Building an EEG study
18.1 What is special about EEG studies?
18.2 Sending EEG triggers
18.3 Communicating by parallel port or LabJack
18.4 Sending EEG triggers by network connections
18.5 Using custom libraries
19 Add eye tracking to your experiment
19.1 Eye tracking in Builder
19.2 Configuring ioHub
19.3 Programming ioHub
19.4 Add eye tracking to the visual search task
19.5 Data storage via ioHub
19.6 Saving image stimuli to disk
19.7 Conclusion
Appendix A Mathematics refresher
A.1 Sine and cosine
A.2 Rescaling and changing start points
A.3 Pythagoras’ Theorem
Appendix B Exercise Solutions
Bibliography
Index
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Acknowledgments
This book wouldn’t have been possible without the help and support of
many people.
Jon is very grateful to the support he has had from his family who have at
times been left holding the baby (literally) while he has spent his evenings
and weekends writing this book. Shiri Einav, in particular, has often had to
fill in the bits of life that he hasn’t been doing while working on this
endeavor! Michael thanks Sarah Kirk and Paige MacAskill for putting up
with his absences on the home front. He’d also like to thank Jon himself,
for creating PsychoPy in the first place, but also setting the tone for the
good-natured and enthusiastic community that has grown up around it. Our
respective institutions (University of Nottingham and New Zealand Brain
Research Institute) have paid us throughout this period and allowed us to
work on these projects, for which we are also grateful.
It hasn’t just been about the writing of the book though. The book couldn’t
have been written without PsychoPy and there are many more people
involved in that project that must all be thanked. PsychoPy is a community
project, driven by people volunteering their time, in between running
experiments and teaching students in their universities. These volunteers
are helping in various ways: some are writing the software itself and fixing
bugs they find; others are helping out on the forum so that new users can
get their questions answered. The people asking those questions also
contribute, by showing where software features aren’t obvious or need
improvement, and what sorts of areas need to be covered in a book like
this.
A few of the contributors need special mention because of the vast number
of hours they have put into the project. Jeremy Gray and Sol Simpson have
both put in ridiculously large amounts of time in both development and
user support. Some very notable features are theirs entirely (like the Rating
Scale and the ioHub) but they have contributed to code across the entire
project. They, and their families, have sacrificed a lot for the sake of this
project, for no financial gain, solely to help users run experiments.
Richard Höchenberger, Hiroyuki Sogo, Jonas Lindeløv, Damien Mannion,
Daniel Riggs, Oliver Clark, Yaroslav Halchenko, Jan Freyberg and Eric
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