Dedicated to the memory of Professor John Maynard Smith (6 January 1920 - 19 April 2004)

1
Dedicated to the memory of Professor John Maynard
Smith(6 January 1920 - 19 April 2004)
2

Imitation is natural to man from childhood, one
of his advantages over the lower animals being
this, that he is the most imitative creature in
the world and learns at first by
imitation". Aristotle
3
Cultural transmission of information in
animals has been examined in many contexts

• Foraging

• Predator-prey interactions

• Direction finding

4
Sharped Tail Grouse on a Lek
5
(No Transcript)
6
Why the Guppy?

• Experience with natural system

• Guppies live in groups

• Guppies live in clear water

• Guppies take well to the lab (experiments and
  breeding)

• Much is known about the genetics of guppy mate
  choice

7
The Choice Test Paradigm
Male 2
Male 1
8
Results of Copying Experiment
Time near as a proxy for mate choice
Male 1
Male 2
Model female was near this male
In 85 of trials, females preferred males that
were near model female (G 10.8, P lt 0.005)
9
(No Transcript)
10
Results of Control 1 (Group Size)
Female 2
Female 1
Focal female
In only 50 of trials did focal prefer side
females that were near the model female (G 0).
11
Control Experiment 2
Male 1
Male 2
12
Results of Control Experiment 2
Male 1
Male 2
Model female was near this male
In only 45 of trials did female prefer males
that were near the model female (G 0.2, P gt
0.5).
13
Control 3 (viewed from above)
Male 2
Male 1
Focal female
Female
Female
14
Results of Control 3
Male with visible model
Male
Focal female
In 85 of trials, females preferred males that
were near the visible model female (G 10.8, P
lt 0.005)
15
Control 4
Male 2
Male 1
16
Results of Control Experiment 4
Male 2
Male 1
Model female was near this male, but his position
has shifted
In 80 of trials, female preferred males that
were near model female (G 7.7, P lt 0.01)
17
The relative strength of genetic vs. cultural
transmission
18
What if cultural and genetic transmission are
operating in opposite directions?
Use fish from Paria River
19
Paria River Guppies
20
Protocol
Treatment difference in male color I 4
(matched) II 12 III 24 IV 40
For each treatment, a control is run in the
absence of a model female.
In all treatments, the model is always placed
near less colorful male.
21
Males Differ by 12 - No Model
22
Results (No Model Present)
In 85 of trials, females preferred more
colorful male (G 10.6, P lt 0.005)
23
Males Differ by 12 - Model Near Less Colorful
Male
24
Results Males Differ by 12 - Model Near Less
Colorful Male
In 85 of trials females prefer less colorful
male. A complete reversal of the case when no
model was present.
25
1
0.8
0.6
Proportion choosing more orange male
0.4
0.2
0
0.04 (I)
0.12 (II)
0.24 (III)
0.40 (IV)
Mean difference in orange body color
26
Treatment and control are significantly
different for I, II and III, but not IV
27

• What happens if we make cultural transmission
• more powerful?

• Can we make very drab males attractive?

28
Treatment and control are significantly
different for I, II and III, but not IV
29
(No Transcript)
30
Do individuals generalize the information they
receive through cultural transmission to
phenotypes?
31
Experimental Trials
32
Control Trials
33
(No Transcript)
34
The Long Reach of Cultural Transmission
35
From date copying in guppies to date copying in
humans?
36
Study 1

• N 60 males 74 females
• All were volunteers, part of a requirement for
  General Psychology class
• Median age of males 21
• Median age of females 23

37
Survey (for females) - Study 1
Chris was interviewed independently by five
women. Each interview lasted 20 minutes and the
interviewer was allowed to ask anything she
wanted. The five women then rated Chris on
several characteristics. These ratings were made
using 10-point scales, where the higher the
number, the more positive the rating.
In terms of physical attractiveness, Chris
average rating was 3 out of 10 (where 1
extremely unattractive and 10 extremely
attractive)....
In addition, the five women were asked to
indicate how interested they would be in dating
Chris. 4 of the 5 women indicated an interest
in dating Chris.
38
Questionnaire - Study 1
1. How interested would you be in dating
Chris? Not at all Very 1 2 3 4 5 6 7 2. How
good do you think Chris social skills are? Not
good at all Very good 1 2 3 4 5 6 7 3. How
good do you think Chris sense of humor is? Not
good at all Very good 1 2 3 4 5 6 7 4. How
wealthy do you think Chris is? Not wealthy at
all Very wealthy 1 2 3 4 5 6 7
39
Results of Study 1

• Physical attractiveness effect was significant
  with high
• physical attraction targets eliciting a greater
  response
• than low physical attraction targets (P lt 0.005
  for both sexes).
• No physical attractiveness x gender interaction.

40
Results of Study 1 - Cont

• Main effect of peer attention (p lt 0.0001), with
  high
• peer attention gt medium peer attention (p lt
  0.0001, for both
• sexes) and medium gt low peer attention (p lt
  0.001 , for both
• sexes).
• Significant gender x peer attention effect.
  Females were
• more affected by differential peer attention than
  were
• males (p lt 0.01).

41
Results of Study 1 - ContAttributes

• Social skills - both males and females thought
• high peer attention individuals had better social
  skills
• than medium (p lt0.01) or low peer attention
• individuals (p lt 0.0001). No interactions with
• physical attractiveness or gender.
• Sense of humor - same as social skills.

42
Results of Study 1 - ContAttributes

• Wealth - both males and females thought high
• peer attention individuals were wealthier
• than either low or medium peer attention
  individuals.
• There was, however, a significant peer attention
  x
• gender interaction, with females perceiving
  greater
• differences in male wealth as a function of peer
• attention.

43
Results of Study 1 Summary

• Both males and females are affected by physical
  attraction.

• Both males and females engage in date copying.

• Females weigh the decisions of others more
  strongly than males.

• Both sexes attribute social skills, a sense of
  humor and wealth to
• those individuals preferred by others.

• Females associate peer attention and wealth more
  strongly than
• males.

44
Where to from here?
45
Time permitting
46
The Spread of Information Through a
Group Cultural Transmission and Chain Links
47
Experimental Treatment
48
Experimental Treatment
1 Link
O Links Trial ends
49
Experimental Treatment
50
Experimental Treatment
2 Links
1 Link Trial ends
51
(No Transcript)
52
Control Treatment
1 Psuedo Link
O Pseudo links Trial ends
53
(No Transcript)
54
Control Treatment
2 Psuedo Link
1 Pseudo links Trial ends
55
Results
2.85 ( 1.47)
Mean Number of Links Or Pseudolinks
1.00 ( 1.03)
Treatment Control
Two tailed t-test 4.48, df38, P lt 0.0001