Edinburgh Handedness Inventory

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The Edinburgh Handedness Inventory is a measurement scale used to assess the dominance of a person's right or left hand in everyday activities, sometimes referred to as laterality. The inventory can be used by an observer assessing the person, or by a person self-reporting hand use. The latter method tends to be less reliable due to a person over-attributing tasks to the dominant hand.


The Edinburgh Handedness Inventory was published in 1971 by Richard Charles Oldfield [1] and has been used in various scientific studies [2] [3] as well as popular literature. [4]

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In human biology, handedness is the better, faster, or more precise performance or individual preference for use of a hand, known as the dominant hand. The incapable, less capable or less preferred hand is called the non-dominant hand. Right-handedness is most common; about 90% of people are right-handed. Handedness is often defined by one's writing hand, as it is fairly common for people to prefer to do some tasks with each hand. There are examples of true ambidexterity, but it is rare—most people prefer one hand for most purposes.

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The octave illusion is an auditory illusion discovered by Diana Deutsch in 1973. It is produced when two tones that are an octave apart are repeatedly played in alternation ("high-low-high-low") through stereo headphones. The same sequence is played to both ears simultaneously; however when the right ear receives the high tone, the left ear receives the low tone, and conversely. Instead of hearing two alternating pitches, most subjects instead hear a single tone that alternates between ears while at the same time its pitch alternates between high and low.

Cerebral hemisphere The left and right cerebral hemispheres of the brain

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The term laterality refers to the preference most humans show for one side of their body over the other. Examples include left-handedness/right-handedness and left/right-footedness; it may also refer to the primary use of the left or right hemisphere in the brain. It may also apply to animals or plants. The majority of tests have been conducted on humans, specifically to determine the effects on language.

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Planum temporale

The planum temporale is the cortical area just posterior to the auditory cortex within the Sylvian fissure. It is a triangular region which forms the heart of Wernicke's area, one of the most important functional areas for language. Original studies on this area found that the planum temporale was one of the most asymmetric regions in the brain, with this area being up to ten times larger in the left cerebral hemisphere than the right.

Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other. It is somewhat analogous to the laterality of right- or left-handedness; however, the side of the dominant eye and the dominant hand do not always match. This is because both hemispheres control both eyes, but each one takes charge of a different half of the field of vision, and therefore a different half of both retinas. There is thus no direct analogy between "handedness" and "eyedness" as lateral phenomena.

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A relationship between handedness and sexual orientation has been suggested by a number of researchers, who report that heterosexual individuals are somewhat more likely to be right-handed than are homosexual individuals.

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Left-handedness always occurs at a lower frequency than right-handedness. Generally, left-handedness is found in 10.6% of the overall population. Some studies have reported that left-handedness is more common in twins than in singletons, occurring in 21% of people who are twins. However other studies did not find a higher left-handedness prevalence in twins compared to singletons.

Bias against left-handed people is bias or design that is usually unfavorable against people who are left-handed. Part of this is due to design in the world which is often right-hand biased. Handwriting is one of the biggest sources of actual disadvantage for left-handed people, other than for those forced to work with certain machinery. About 90 percent of the world's population is right-handed, so many common articles are designed for efficient use by right-handed people, and may be inconvenient, painful, or even dangerous for left-handed people to use. These may include school desks, kitchen implements, and tools ranging from simple scissors to hazardous machinery such as power saws.

Yakovlevian torque

Yakovlevian torque is the tendency of the right side of the human brain to be warped slightly forward relative to the left and the left side of the human brain to be warped slightly backward relative to the right. This is responsible for certain asymmetries, such as how the lateral sulcus of the human brain is often longer and less curved on the left side of the brain relative to the right. Stated in another way, Yakovlevian Torque can be defined by the existence of right-frontal and left-occipital petalias, which are protrusions of the surface of one hemisphere relative to the other. It is named for Paul Ivan Yakovlev (1894–1983), a Russian-American neuroanatomist from Harvard Medical School.

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Paul Satz was an American psychologist, and one of the founders of the discipline neuropsychology. His research on the relationship between the brain and human behavior spanned diverse topics including laterality, handedness, and developmental disorders. He published over 300 publications, received numerous grants and awards, and established the first neuropsychology lab. Towards the latter part of his career, Satz's research interests focused more on the cognitive deficits associated with head injury, dementia, and ageing.

An estimated 90% of the world's human population consider themselves to be right-handed. The human brain's control of motor function is a mirror image in terms of connectivity; the left hemisphere controls the right hand and vice versa. This theoretically means that the hemisphere contralateral to the dominant hand tends to be more dominant than the ipsilateral hemisphere, however this is not always the case and there are numerous other factors which contribute in complex ways to physical hand preference.


  1. Oldfield, RC (March 1971). "The assessment and analysis of handedness: The Edinburgh inventory". Neuropsychologia. 9 (1): 97–113. doi:10.1016/0028-3932(71)90067-4. PMID   5146491.
  2. Verdino, M; Dingman, S (April 1998). "Two measures of laterality in handedness: the Edinburgh Handedness Inventory and the Purdue Pegboard test of manual dexterity". Perceptual and Motor Skills. 86 (2): 476–8. doi:10.2466/pms.1998.86.2.476. PMID   9638746.
  3. Knecht, S; Dräger, B; Deppe, M; Bobe, L; Lohmann, H; Flöel, A; Ringelstein, E-B; Henningsen, H (December 2000). "Handedness and hemispheric language dominance in healthy humans". Brain. 123 (12): 2512–8. doi: 10.1093/brain/123.12.2512 . PMID   11099452.
  4. Wolman, David (2006). A left-handed Turn Around the World. ISBN   978-0-306-81498-3.