В этом докладе будет рассмотрена тема психологии тестирования: то, что лежит на поверхности, но почему-то не принимается во внимание при принятии решений, в сложных ситуациях. Почему важно задуматься над тем, «как мы думаем» и «почему мы думаем именно так». Рассмотрим, как тесно связана психология и тестирование программного обеспечения, как предубеждения мешают тестировщикам думать рационально и принимать правильные решения. Все это - на реальных примерах. И, конечно же, несколько совеов по обхождению ловушек мышления.

2. Software Testing
Biases
Oksana Shatabilova
Senior QA Engineer DataArt

3. Content
• Cognitive biases
• Emotions
• Education and training others
• System 2 thinking

4. Cognitive bias
• Princeton University has the following definition for cognitive bias:
“Cognitive bias is a general term that is used to describe many
observer effects in the human mind, some of which can lead to
perceptual distortion, inaccurate judgement, or illogical
interpretation. It is a phenomenon studied in cognitive science
and social psychology.”
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5. “You should work to reduce your biases, but
to say you have none is a sign that you have
many” - Nate Silver
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6. Confirmation Bias
“Confirmation bias is a filter through which you see
a reality that matches your expectations. It causes
you to think selectively, but the real trouble begins
when confirmation bias distorts your active pursuit
of facts. - David McRaney”
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7. Key Points
• Ensure that more than one tester tests the same feature
• “Paired testing” either with dev or tester or user
• Automated testing
• Keep in mind “confirmation bias” during communication activities
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8. Cognitive dissonance
Cognitive dissonance is
an uncomfortable feeling
caused by holding
conflicting ideas
simultaneously.
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9. Conjunction effect
Linda is 31 years old, single, outspoken, and very bright. She
majored in philosophy. As a student, she was deeply concerned
with issues of discrimination and social justice, and also participated
in anti-nuclear demonstrations.
Which is more probable?
A.Linda is a bank teller.
B.B. Linda is a bank teller and is active in the feminist movement.
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10. Test
• Req1: If the user is a software engineer then screen ‘is engineer’
must be shown.
• Req2: If the user is a software engineer and likes to listen to
classical music then screen ‘music engineer’ must be shown.
Let us look at the following user story.
• David went to university to train as a classical violinist. Once
leaving university David retrained as a software engineer and
started to write code for a major software house. Which is
more likely to be true? 10

11. Cognitive framing
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12. Illusory Correlation
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Illusory correlation is the
phenomenon of seeing
the relationship one
expects in a set of data
even when no such
relationship exist.

13. Cognitive Illusions
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14. Cognitive Illusions
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15. Cognitive Illusions
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16. Key Point
Beware of your own
beliefs, assumptions and
that of others on your
team.
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17. Emotions
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18. The Emotional Tester
• Do we find more bugs when we are in a bad mood? Psychology research
shows we are more negative when in bad mood.
• How many testers when testing listen to music?
• If you are working in an open plan office and everyone around you is
laughing and joking would this make your testing better or worse?
• What if a tester and a developer are having a heated debate about a
feature that has just been tested?
As testers we need to be aware of our emotions and how they can
affect the quality of the testing we are doing.
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19. Did you make a right decision?
This is crucial when we are making decisions based upon how we feel. We
need to ask ourselves the following before committing to any decision:
• Do we know the subject?
• Are we being influenced by our biases?
• Have we thought critically about why we are feeling this way?
• Is there a personality issue which is causing us to feel the way we do?
• Are there other motivations in play that affects how we are feeling?
Rewards, Bonus, Promotion?
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20. How often do you take a part in interview?
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21. Key Point
Being aware of how you feel could be useful to help you realize
what you may have missed when you are testing.
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22. Education and Training Others
“We now accept the fact that
learning is a lifelong process
of keeping abreast of change.
And the most pressing task is
to teach people how to learn.”
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23. Training Courses
• “Sit back and listen”
• “Learn by doing”
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24. Experiential Learning
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25. Self Learning
• Attention: What subject draws your attention in leading you
to want to learn more?
• Relevance: How is this subject relevant to you and why do
you want to learn more about it?
• Confidence: How sure that you will be able to commit to
learning this subject? Is the value to you of learning this
subject high?
• Satisfaction: Is learning this subject useful to you? What are
your reasons for learning this subject? Entertainment?
Sense of achievement? Praise? 25

26. Why not?
Many people make excuses not to
learn:
• I don’t have the money
• I don’t have the time
• I don’t have the skills
• I don’t need to
• I rely on certifications for all of
my training
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27. Conferences
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28. Key Point
The majority of self learning is free with regards to money the
only thing to give up is some time. It is a wise investment to
put some of your own time aside to learn.
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29. Mentoring and Coaching
“No one learns as much
about a subject as one who is
forced to teach it.”
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30. System 2 thinking
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31. Test
“A rat and ball cost $1.10. The
rat costs one dollar more than
the ball. How much does the
ball cost?”
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32. Answer
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x+y=1,10
x=y+1
y+1+y=1,10
2y=1,10-1
2y=0,10
Y=0,05

33. Test 2
“How many animals did Moses take into the Ark?”
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34. Key Point
“I would like to remind people involved in testing that—after an
engaged brain—one of our most useful testing tools is… the
pause….” - Michael Bolton
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35. 16 Steps to become a critical
thinker
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36. Q&A
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37. Thank you for
attention!