Irrational Decision Making in Non-Humans: A Critical Review of Comparative Cognition Context Effect Research

2. Asymmetric dominance
Megapixel
Price
s
A 8 $800
$1,000 > $1,200 but $800
B 10 > {8, 9}
> $1,000
C9 $1,200
Camera B totally dominates camera C on megapixels and price, but only
dominates camera A on megapixels  Camera B asymmetrically
dominates cameras A and C

3. [Ir]rationality
1. Independence of irrelevant alternatives (IIA)
2. Regularity
3. Sometimes: transitivity
Result in preference reversals
Violating one or all of these rules indicates
the use of a comparative vs. absolute
valuation rule

4. Study Animal Choice Sets IIA Reg. Trans. Note
Latty and unicellular slime BIN vs. TRI x x* *only starved
Beekman molds (P.
(2010) polycephalum)
Shafir (1994) honey bees (Apis BIN x effort
mellifera) attribute
Shafir, Waite, honey bees (Apis BIN vs. TRI x no effort
and Smith mellifera) and attribute
(2002)
Shafir, Waite, Gray jays (P. BIN vs. TRI x x effort
and Smith canadensis) attribute
(2002)
Hurley and hummingbirds BIN vs. TRI x risk attribute
Oseen (1999) (Selasphorus
rufus)
Bateson, Healy, hummingbirds BIN vs. TRI x x x
and Hurley (Selasphorus
(2002, 2003) rufus)
Waite (2001) Gray jays (P. BIN x x
canadensis)
Scarpi (2010) (Felis catus) BIN vs. TRI* x x *phantom
decoys
x = violation | no = no violation | blank = unknown

5. [Ir]rationality?
Bigger question: Is this actually irrational?
1. It occurs in all sorts of animals, from unicellular
organisms, to birds, cats, and humans
It would be surprising if natural selection didn’t
correct this if it were truly bad for us
2. It’s probably not a side effect of a shared cognitive
mechanism
Perhaps it’s rational?
Or perhaps we’ve just Or perhaps we’ve just
defined utility in the wrong defined rationality in the
way? wrong way?

6. Theories
Decision Field Theory
•
1. Actors calculate utilities at every moment when their focus changes
Independence of irrelevant alternatives
• Preferences along dimensions are evaluated over time and a choice is
(IIA)
made when the preference exceeds a threshold
•
2. Context effects cause dimensional weights to shift
Regularity
• Size of context effect depends on time to make decision Problem:
3. Utility still doesn’t represent the underlying value of an option to
Sometimes: transitivity
reproductive success
Redefining Utility (Samuelson & Swinkels, 2006)
Economist: you’re irrational
• From Friday’s presentation
• Context effects = evolutionarily advantageous because it allows actors
to learn about choices