The slides for Marianne Talbot's talk on Action Theory at UX Brighton

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2. Thank you for inviting me to speak
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3. In designing a website one of your aims is
to stimulate action
This is almost certainly the main aim of
your employer
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4. There are all sorts of different actions you might want to
stimulate
• buying
• following
• liking
• clicking through
• recommending
• reviewing
often you’ll want to stimulate several actions
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5. Well action is something that philosophers
know a lot about
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6. Distinguish tripping over a carpet and
pretending to trip over a carpet – which is
an action and why?
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7. Pretending to trip over a carpet is an
action because:
• it is chosen
• it is performed intentionally
• it is performed for reasons
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8. When human beings act they make
choices
When human beings make choices they do
so for reasons
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9. If we want to understand action,
therefore, and how to stimulate it, it
is necessary to understand reason
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10. To be rational is to be such that some of
your behaviour is reason-driven
Most rational things are such that most of
their behaviour is non-rational
To be rational is to be capable of being
irrational
Non-rational things are neither rational
nor irrational
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11. What is a reason?
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12. A reason-driven behaviour (an
action)…
… is a behaviour caused by a
combination of desires and beliefs
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13. Desires and beliefs are both mental
states…
… but they differ from each other
quite radically
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14. Desires and beliefs play different
roles in the production of action
Desires and beliefs have a different
relation to reason
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15. Desires motivate action
Beliefs guide action towards its goal
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16. It is not possible to reason anyone
into a desire
It is only beliefs that we can be
reasoned into
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17. I understand that ‘UX’ stands for ‘User
Experience’…
… and that it was born because your
main aim in designing a website…
… is to provide the user with
whatever he or she wants
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18. Unless you are offering something the
user wants you’ll never get anywhere
But the user’s wants – desires – are only
half the picture
The user’s beliefs about how to fulfil his
desires are the other half
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19. In fact given that there is little you can do
about your users’ desires…
… your main aim (I respectfully
submit!)…
… should be to give your user the
belief that…
…by using your website he can fulfil
(some of) his desires 19

20. So let’s consider the nature of beliefs
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21. • all beliefs have contents
• the contents of beliefs are constituted of
concepts
• every belief is related to every other belief
• beliefs admit truth and falsehood
• beliefs are expressed in sentences
• human beings care (to some extent) about
the truth of their beliefs
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22. Relations between beliefs can be:
• rational
• irrational
• non-rational
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23. A rational relation between beliefs:
Belief one: Marianne always wears
jeans on a Friday
Belief two: It is Friday
Belief three: Marianne is wearing jeans
The rational relation between these beliefs is
entailment
If beliefs one and two are true, belief three
must be true 23

24. These beliefs amount to a deductive
argument
Premise one: Marianne always
wears jeans on a Friday
Premise two: It is Friday
Conclusion: Marianne is wearing
jeans
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25. All arguments are relations between
beliefs such that…
…one belief is the conclusion…
… and the other beliefs are its
premises …
…(the reasons given for the
conclusion)
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26. There are two types of argument:
• deductive arguments
• inductive arguments
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27. Deductive arguments give us certainty
(conditionally on the truth of the
premises)
Valid deductive arguments are conclusive
Valid deductive arguments can be
evaluated a priori
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28. P1: All doodahs are whotsits
P2: All whotsits are green
C: This doodah is……
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29. Irrational relations between beliefs:
Premise one: Marianne always
wears jeans on a
Friday
Premise two: Marianne is wearing
jeans
Conclusion: It is Friday
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30. Non-rational relations between
beliefs:
Premise one: I want my spouse
to be faithful
Conclusion: My spouse IS
faithful
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31. Inductive reasoning takes us from observations of
the past to predictions about the future:
P1: I have seen the sun rise every day in the
history of the universe
C: I expect the sun to rise tomorrow
Inductive reasoning is hugely important to human
beings
Inductive argument is central to science
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32. Huge philosophical controversy: is
induction rational?
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33. The Scottish Philosopher David
Hume noted that…
… every inductive argument
contains a hidden premise…
… that nature is uniform (the
future will be like the past)
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34. This premise cannot be justified
• deductively (it generates no
contradiction to believe that nature is
not uniform)
• inductively (we’d be arguing in a
circle)
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35. Hume argued that induction is non-
rational
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36. But it is clear that we can distinguish
between good inductive arguments and bad
inductive arguments:
Women who drink this brand of vodka
are beautiful, rich and attract the most
handsome men
If I drink this vodka I will become
beautiful, rich and start attracting the
most handsome men
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37. Philosophers live in hope of finding a
systematic way to distinguish
between good and bad inductions
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38. Summary:
• actions are reason-driven
• for an action to be reason-driven is for it to be:
• motivated by desire
• guided by belief
• it is not possible to argue anyone into a desire
• if you want to satisfy users’ desires it is their beliefs you
need to address
• users’ beliefs can be changed and brought into being
rationally, irrationally or non-rationally
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39. If you want to inspire trust it is
always better to change someone’s
beliefs by rational means!
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