LEFT vs Right

Measuring Handedness

Estimates for the prevalence of left-handedness vary significantly - anywhere between 2% and 30% - reflecting the ambiguities and inconsistencies inherent in the defining handedness, but also sometimes the biases and unreliability of the sources. In more formal cultures that stress conformity, such as Asian, Muslim and Latin American countries, the rates tend to be lower. Korea (2%), Japan (3%) and Taiwan (5%) have the lowest levels of left-handedness. In few places men are not twice likely to be left handed than women. Interestingly, left-handedness is almost twice as likely among twins as among the general population. Ex-US President Gerald Ford supposedly wrote left-handed when sitting down and right-handed when standing up. So is it cross dominance or mixed handedness? that is actually decided by few methods which are mentioned below.

Now when it comes to mixed handedness some estimates claim that as many as 30% within the developed world may be classified as "non-right-handed" they can't be called exactly left-handed or ambidextrous. So how do we measure this? the answer is complicated and we have different methods basically classified into 2 types. It is not sufficient to merely ask a person whether they are right-handed or left-handed. There are too many variables and uncertainties involved, which can too easily lead to anomalous results.

Methods of researchers to assess handedness:

(a)Testing for preference

The listing of various activities which are used in daily life and asking which hand one would prefer to do those works. For example using scissors,computer mouse, throwing and catching the ball, brushing the teeth, eating, writing, using knife, phone and batting etc. The list which is prepared consists of activities that really show our dominance towards hands. There is a link here "http://leftyfretz.com/left-handed-test/" which provides such questions and answers which will be given are interlinked and it calculates the percent handedness.

Testing for hand preference is easy and is cost-effectively ascertained by means of a questionnaire or survey. The activities for preference include writing, drawing, throwing a ball, eating with spoon, cutting with knife, use of hand in different kind of sports, opening jar, brushing the teeth, polishing shoe, arm wrestling etc. Basically a person who performs half or more of these everyday tasks with their left hand is considered left-handed, although the percentage of "strong left-handers", who perform all of these tasks with their left hand, is way too smaller. Depending on the study and its requirements, those who score 5 or 4 (or even 3 or 2 such that those are particular questions which are critical and "Big Three") out of 10 may be categorised as mixed-handed. The score is marked such that if one answers left hand the he is given a point or if he answers right he is given 0 points.

The "Big Three" tasks are writing, eating and throwing, and these alone are usually sufficient to define a person's handedness for most simplistic purposes (although writing is also the handed activity most likely to be influenced by social pressures to conform).T here are several kinds of errors which routinely creep into such tests. For example, people often tend to respond in the way they think the questioner would expect, the way they think they ought to answer; sometimes they may err in the other direction, offering the researcher a deliberately non-conformist answer they think he will find interesting, even if it is not actually accurate; or they may just answer incorrectly in good faith in themselves but having no real idea of which hand they typically use for that specific task. The most commonly-used handedness survey today is the Edinburgh Handedness Inventory, a simplified questionnaire designed by R.C. Oldfield, but based on a more detailed questionnaire originally created by the English psychologist Marian Annett in 1970. You can test your handedness by going to links "http://hunternuttall.com/resources/handedness/"