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Studies

Plomin et al. (1993): study US Colorado 1986

Publication

Author(s):
Plomin, R.; Braungart, J.M.; Campos, J.J.; Corley, R.P.; DeFries, J.; Emde, R.N.; Fulker, D. W.; Kagan, J.; Reznick, J.S.; Robinson, J.L.; Zahn-Waxler, C.
Title:
Genetic change and continuity from fourteen to twenty months: The MacArthur Longitudinal Twin Study
Source:
Society for Research in Child Development; Child Development, 1993, 64, 1354-1376

Investigation

Public:
Same-sex twins, Colorado, United States, followed from 14 to 20 months, 1986-1989
Sample:
Non-probability purposive sample
Respondents:
N = 398
Non Response:
Assessment:
Behavioural observation
At 14 months: observation at home, 2 weeks later observation in laboratory

Happiness Measure(s) and Distributional Findings

Full text:
Time sampled ratings of positive and negative affect made from video recordings of child behavior; 30 second intervals across 15 minutes of free play and 1minute intervals for 4 alternate 5 minute segments of the Bayley test

Assessment of discrete behaviors; observation schedule not reported

Rated on 4 step scale, scale labels not reported
Classification:
A-AB-mi-tsb-?-4-a
Author's label:
Hedonic tone, positive and negative
Remarks:
Affect Balance computed by WDH team;
14 months: boys: M=0.89;  girls: M=1.01
20 months: boys: M=1.05;  girls: M=1.09
(overall mean computed by WDH team)

Positive Affect:
14 months: boys: M=2.27 sd=.24;  girls: M=2.35 sd=.25
20 months: boys: M=2.35 sd=.25;  girls: M=2.38 sd=.27

Negative Affect:
14 months: boys: M=1.38 sd=.33;  girls: M=1.36 sd=.31
20 months: boys: M=1.30 sd=.27;  girls: M=1.29 sd=.31
Page in publication:
1337, 1362
Observed distribution
Frequencies
1: 0%,   2: 0%,   3: 0%,   4: 0%
Summary Statistics
On original range 1 - 4 On range 0-10
Mean:
1.01
Full text:
Time sampling of prevalent mood during free play and Bayley test. Average of observations at 30 second intervals across 15 minutes of free play and 1 minute intervals for 4 alternate 5 minute segments of the Bayley test

Rated on 7 step scale, scale labels not reported
Classification:
A-CA-mi-tsb-v-7-a
Author's label:
Overall Mood
Remarks:
14 months: boys: M=4.6 sd=1.1;  girls: M=4.9 sd=1.1
20 months: boys: M=4.9 sd=1.1;  girls: M=5.0 sd=1.2
Page in publication:
1357, 1362
Observed distribution
Frequencies
1: 0%,   2: 0%,   3: 0%,   4: 0%,   5: 0%,   6: 0%,   7: 0%
Summary Statistics
On original range 1 - 7 On range 0-10
Mean:
4.85 6.42
SD:
1.13 1.88

Correlational Findings

Author's label Subject Description Finding Happiness at 14 and 20 months Recent happiness (< 1 year ago) Happiness of twin siblings Happiness of siblings
Happiness of sibblings
Gender Sex (male vs female)