Leveraging Cognitive
Bias in Social Design
Rationality be damned.
Joshua Porter
Purveyor: bokardo.com
UX guy: chi.mp
d.Construct
2008 author of

Q: Which restaurant
would you choose?

http:// ickr.com/photos/elgrandee/1819133411/

http:// ickr.com/photos/albedo/110329014/

Bandwagon
E ect
the observation that people often do
and believe things because many
other people do and believe the same
things

Heuristics
When people are faced with a complicated judgment or decision, they
often simplify the task by relying on heuristics, or general rules of thumb.
In many cases, these shortcuts yield very close approximations to the
“optimal” answer, that which results from purely rational thinking.
Gather all information necessary
Uncertainty
for rational judgment
Heuristic
(shortcut)
Make decision

Cognitive Biases
In certain situations, heuristics lead to predictable biases and
inconsistencies.
Gather all information necessary
Uncertainty
for rational judgment
Heuristic
(shortcut)
Bias Make decision

A few design-related biases
Lake Wobegon e ect the phenomenon that a supermajority of people report
themselves as above average in desirable qualities
Self-serving bias the tendency to claim more responsibility for successes than failures
Optimism bias the systematic tendency to be over-optimistic about
the outcome of planned actions
Not invented here the tendency to ignore that a product or solution
already exists, because its source is seen as an \"enemy\"
or as \"inferior\"
Hindsight bias also known as the ‘I-knew-it-all-along e ect’
Prediction bias the tendency to underestimate the time and cost of work
Fun reading: http://en.wikipedia.org/wiki/List_of_cognitive_biases

Judgment under Uncertainty:
Heuristics and Biases (1974)
Daniel Kahneman & Amos Tversky
Proposed theory: people do not make fully rational
decisions, they use rules of thumb
(heuristics) instead

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
antinuclear demonstrations. Please check o the
most likely alternative.
Linda is a bank teller.
Linda is a bank teller and is active in the feminist
movement.

Feminist
Bank Tellers Bank Tellers Feminists
~90% choose “feminist bank tellers”, although that cannot be the case.

Representation Bias
As the amount of detail in a scenario increases, its probability
can only decrease steadily, but its representativeness and
hence its apparent likelihood may increase.

Leveraging the representation bias
(people will assume that these examples are representative of the group)

Leveraging the representation bias
(people will assume that these examples are representative of the group)

Would you accept this bet?
50% chance of gaining
£100
50% chance of losing
£100

Would you accept this bet?
50% chance of gaining
£200
50% chance of losing
£100

Would you accept this bet?
50% chance of gaining
£300
50% chance of losing
£100

Loss Aversion
Losses loom larger than gains

Feature described in terms of gain:

Feature described in terms of loss:
josh.mp

Feature described in terms of future savings:
Would it be more e ective framed as an immediate loss?
(e.g. Don’t lose the ability to track your package)

What is more valuable to you?
a) A co ee mug on sale
at the local convenience
store
b) The co ee mug that
your future husband/
wife gave you during
that amazing autumn
morning last year when
they proposed to you.
http:// ickr.com/photos/studiosmith/2559034807/

Ownership Bias
People value things more when they feel a sense of
ownership

The Sign-up Problem (the 9x e ect)
Because of loss aversion Because of the ownership
and the ownership e ect, e ect and the optimism
people tend to overvalue bias, software makers
the software they 3x 3x tend to overvalue what
currently use by about a they o er by about a
9x
factor of 3. factor of 3.
Harvard Business Review, June 2006
further reading Eager Sellers, Stony Buyers
by John T. Gourville

Thank you.
Contact?
http://twitter.com/bokardo
porter@bokardo.com