Download Family Niche

Birth order, conscientiousness, and
openness to experience:
Tests of family-niche model of personality using a within-family
methodology
Maddie Rauzi and
Dylan Antovich
Introduction: Salloway’s Theory

Ernst & Angst (1983) – No birth order effects on personality when
socioeconomic status and family size are taken into account.
 Salloway(1996, 2001) challenged their conclusion and offered a new
perspective. Sibling competition leads children to cultivate niches with
the family.
 Firstborns = receive more investment from parents and aim to fulfill
parents’ expectations.

more conscientious, responsible, ambitious, organized, academically
successful, traditional and conservative, and more likely to endorse
conventional mortality.
 Laterborns = try and find a niche not already filled by older siblings, and
face domination/bullying by older siblings.

identify less with parents, more open to experience, more likely to
emphasize with downtrodden, be supportive of egalitarian social change,
question the status quo, and to resist authority and conformity.
Author’s points:
1) Salloway’s theory concerns differences WITHIN families.

Disparities between SIBLINGS lead siblings to adopt different strategies for
receiving parental investment.

Within-family research designs (asking siblings to rate each other) yield
significant birth order effects, unlike between-family designs.
2) Competition between siblings promotes differentiation in order to
alleviate conflict, and thus siblings farther apart in age will be less
different.

Strongest birth order differences in siblings 2- 5 years in age, and between
siblings who are ordinally closer

“functional birth order” is important, blending/changing of the family creates
too many confounds.

Differences between firstborn and secondborn brothers more pronounced than
firstborn and secondborn sisters [ H Y antigen ].
Hypothesis:
 Firstborns are more Conscientious (eg responsible,
organized, and academically achieving)
 Laterborns are more Open to Experience (rebellious,
unconventional, and liberal)
Study 1: Methods
 Second-year Personality Psychology students!
 Listed all siblings in order of birth, provided their siblings’
ages, sex, relationship to respondent, and coresidence status.
 Rank ordered their siblings on six personality traits:
“rebellious”, “noncomformist”, “open to new experience”,
“responsible/organized”, “scholastically achieving”, and
“liberal”.
 Of 209 questionnaires, 161 were used.
 Avg firstborn = 25.6 years and avg secondborn= 23 years.
Study 1: Results
 Hypothesis supported!
 However, bigger
effect between
female-female
siblings compared to
male-male siblings.
Study 2: Birth order effects in an
older sample
1st study had one major criticism:
Use of university aged population
(college student = high achieving, goal oriented,
high school sibling = angsty, rebellious teen)
To control for this, the second study was sent (by mail) to
an older population (the New Zealand Coast-to-Coast
Endurance racers)
Study 2: Methods

Questionnaires mailed to 750 participants:

Same questionnaire format used, but with different items:
Rebellious, lazy, nonconformist, open to new experiences,
responsible/organized, conventional, scholastically achieving and
liberal

237 were returned

174 were completed correctly



First born and second born had to be 1.5 to 5 years apart
Siblings had to be raised together w/out intervening step
or half siblings
Average age of firstborns was 37.5
Study 2: Results
The adjectives from the survey were assigned to two
categories, as with the first study:
 Openness to Experience defined as:
Rebellious, open to new experience, liberal,
nonconformist, and conventional (reverse coded)
 Conscientiousness defined as:
Lazy (reverse coded), responsible/organized, and
scholastically achieving
The adjectives within each group were correlated by r> .30
Study 2: Results cont.
Predictions from
Sulloway’s theory
were confirmed
 Firstborns scored
significant lower on
openness to experience
(p = .002)
 Secondborns scored lower
on conscientiousness
(p = .04)
Study 2: Results cont.
 In order to test Beer and Horn’s prediction
(hypermasculinization of male firstborns) they also
separated male-male and female-female sibling pairs
 The effect predicted by this theory did not hold true
 Effect size for
male-male
female-female were larger than
General Discussion:
 This study was effective at:
 ensuring within-family comparisons were made
 ensuring that only full siblings were compared
 ensuring that siblings were raised in the same family
 This had not been met in previous studies, leading to
environmental confounds
 Both studies found effects as predicted, but the first
study showed greater disparity in Openness to
Experience
General discussion cont.
 The evolutionary perspective:
 This data supports the family-niche theory of personality, in
which offspring must behave differently too compete for
parental resources
 This mechanism shapes the individual fitness of the offspring,
permanently altering behavior patterns, creating
personality
Questions we have about this study:
 These data are self-report (and more importantly, reporting for
subjective opinions of siblings)… sibling rivalry?
 There is no explanation about how being rebellious from
parents would improve fitness from resource competition…
how is it beneficial?
 How do OTHER siblings fare under the birth-order assumption
of personality – separate mechanism?
 Can we conclude much about “Personality” based on the
measure of one trait – “Conscientiousness/Openness to
Experience”?
 What about twins? Do they compete? (*cough* Laura and Kyle)