The Family and Kinship
• Webster, G. D. (2003). Prosocial behavior in
families: Moderators of resource sharing.
Journal of Experimental Social Psychology, 39,
644-652.
By Cristina Perez, Stephanie Taylor, Grace Gayles
Prosocial Behavior
Based on Hamilton’s theory of inclusive
fitness:
“ an individuals relatives are all vehicles of
fitness, but they differ in value (Buss, 2008).”
Kin-based altruism:
Helpers sacrifice their own safety or
resources toward their young.
Webster, G. D. (2003). Prosocial behavior in
families: Moderators of recourse sharing.
Journal of Experimental Social Psychology,
39, 644-652.
Factors influencing resource
allocation towards relatives
1) Genetic Relatedness *
2) Relatedness Uncertainty *
3) Wealth and Sex *
Willard-Trivers Hypothesis
4) Health and age
5) “Everyday” or “life-or-death” situations
Webster, G. D. (2003). Prosocial behavior in
families: Moderators of recourse sharing.
Journal of Experimental Social Psychology,
39, 644-652.
Methods of Study
-173 Participants ( 77 Female, 96 Male)
-Random assignment into 3 different
lottery groups: $10,000; $100,000;
$1M.
-Task: Allocate money to blood relatives
-Response Sheet
Webster, G. D. (2003). Prosocial behavior in
families: Moderators of recourse sharing.
Journal of Experimental Social Psychology,
39, 644-652.
Results
$10K
$1M
percent of lottery allocated
35.00%
30.00%
28.80%
25.00%
23.30%
20.00%
15.00%
10.00%
5.00%
0.00%
5.60%
4.20%
R=.125
1
7.70%
5.60%
r=. 225
Shared Genetic Relatedness with Participant
Adapted from Webster, 2003, p.648
r=.5
3
Percent of lottery
allocated
30.00%
25.00%
25.10%
20.00%
15.00%
18%
14.20%
13.10%
10.00%
5.00%
0.00%
0 1Degrees
1 Degree
2
$10K
11.11%
7.50%
23 Degrees
Uncertainty of relatedness to participant
Adapted from Webster, 2003, p.649
$1M
30.00%
Female Participants
Percent of lottery allocated
Male Relatives
Female Relatives
22.30%
21.00%
20.00%
16.60%
12.90%
11.40%
10.50%
10.00%
0.00%
1
2
Lottery Amount
Adapted from Webster, 2003, p.650
3
35
Percent of Lottery Allocated
Male Participants
30
Female Relatives
28.8
25
Male Relatives
25
20.4
19.8
20
16.3
15
13.2
10
5
0
f
$10K
$100K
$1M
Lottery Amount
Adapted from Webster, 2003, p. 650
Critical Review
Strengths:
1) Insight into unconscious factors.
2) Focus on prosocial behavior within
families compared to one’s own kin and non-kin.
3) Application to human populations. We can related to these findings.
Also true for animals in nature?
Weaknesses:
1)Complex mathematics in data analysis.
2)The article could have included psychological factors
3) No mention of parent-offspring conflict and affect on resource allocation.
Webster, G. D. (2003). Prosocial behavior in
families: Moderators of recourse sharing.
Journal of Experimental Social Psychology,
39, 644-652.