R: Studies on the Association between Handedness and...
dat.bourassa1996
R Documentation
Studies on the Association between Handedness and Eye-Dominance
Description
Results from 47 studies on the association between handedness and eye-dominance.
Usage
dat.bourassa1996
Format
The data frame contains the following columns:
study
numeric
study number
sample
numeric
sample number
author
character
(first) author
year
numeric
publication year
selection
character
selection of subjects on the basis of eyedness or handedness
investigator
character
investigator (psychologist, educationalist, or other)
hand_assess
character
method to assess handedness (questionnaire or performance based)
eye_assess
character
method to assess eyedness (see below for classification)
mage
numeric
mean age of sample
lh.le
numeric
number of left-handed left-eyed individuals
lh.re
numeric
number of left-handed right-eyed individuals
rh.le
numeric
number of right-handed left-eyed individuals
rh.re
numeric
number of right-handed right-eyed individuals
sex
character
sex of the sample (combined, male, or female)
Details
The 47 studies included in this meta-analysis examined the association between handedness and eye-dominance (ocular dominance or eyedness). Results are given in terms of 2x2 tables, indicating the number of left-handed left-eyed, left-handed right-eyed, right-handed left-eyed, and right-handed right-eyed individuals. Note that some studies included multiple (independent) samples, so that the meta-analysis included 54 samples in total. Also, for some studies, the combined data of the males and females are further broken down into the two subgroups.
In some studies, there was indication that the selection of subjects was not random with respect to handedness and/or eyedness. While this should not influence the size of the association as measured with the odds ratio, this invalidates those studies for assessing the overall percentage of left-eyed and left-handed individuals.
Handedness was assessed in the individual studies either based on a questionnaire or inventory or based on task performance. Eyedness was assessed based on various methods: E.1 methods are based on task performance, while E.2.a denotes assessment based on a questionnaire. The performance based methods could be further broken down into: E.1.a.i (monocular procedure with object/instrument held in one hand), E.1.a.ii (monocular procedure with object/instrument held in both hands), E.1.b (binocular procedure), E.1.c (a combination of the previous methods), and E.1.d (some other method).
Source
Bourassa, D. C., McManus, I. C., & Bryden, M. P. (1996). Handedness and eye-dominance: A meta-analysis of their relationship. Laterality, 1, 5–34.
Examples
### load data
dat <- get(data(dat.bourassa1996))
### calculate log(OR) and corresponding sampling variance with 1/2 correction
dat <- escalc(measure="OR", ai=lh.le, bi=lh.re, ci=rh.le, di=rh.re, data=dat, add=1/2, to="all")
### overall association between handedness and eyedness
res <- rma(yi, vi, data=dat, subset=sex=="combined")
res
predict(res, transf=exp, digits=2)