Evidence map›Paper›PMID 33884412›Full record

ArticleCerebral cortex (New York, N.Y. : 1991)2021

Left-Handers Are Less Lateralized Than Right-Handers for Both Left and Right Hemispheric Functions.

Leah T Johnstone, Emma M Karlsson, David P Carey

Abstract read
In one paragraph

Article in Cerebral cortex (New York, N.Y. : 1991), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 26 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
26citing papers in PubMed, 2 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

26 citing papers in PubMed, 2 syntheses or guidelines pooled it.

  1. Pooled it
  2. Pooled it
  3. Trial
  4. Reduced prefrontal total choline MRS levels characterize the neurodevelopmental phenotype of bipolar disorder.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026
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  13. Effects of Lateralization of Language on Cognition Among Left-Handers.Neurobiology of language (Cambridge, Mass.) · 2025
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors.

Leah T JohnstoneSchool of Psychology, Perception, Action and Memory Research Group, Bangor Imaging Group, Bangor University, Bangor, LL59 2AS, UK.ORCID 0000-0001-5889-7381
Emma M KarlssonSchool of Psychology, Perception, Action and Memory Research Group, Bangor Imaging Group, Bangor University, Bangor, LL59 2AS, UK.ORCID 0000-0002-9605-1923
David P CareySchool of Psychology, Perception, Action and Memory Research Group, Bangor Imaging Group, Bangor University, Bangor, LL59 2AS, UK.ORCID 0000-0001-8860-9731

Funding

Bangor UniversityLeverhulme Trust RPG-2019-102
6 · The paper itself

Abstract

Many neuroscientific techniques have revealed that more left- than right-handers will have unusual cerebral asymmetries for language. After the original emphasis on frequency in the aphasia and epilepsy literatures, most neuropsychology, and neuroimaging efforts rely on estimates of central tendency to compare these two handedness groups on any given measure of asymmetry. The inevitable reduction in mean lateralization in the left-handed group is often postulated as being due to reversed asymmetry in a small subset of them, but it could also be due to a reduced asymmetry in many of the left-handers. These two possibilities have hugely different theoretical interpretations. Using functional magnetic resonance imaging localizer paradigms, we matched left- and right-handers for hemispheric dominance across four functions (verbal fluency, face perception, body perception, and scene perception). We then compared the degree of dominance between the two handedness groups for each of these four measures, conducting t-tests on the mean laterality indices. The results demonstrate that left-handers with typical cerebral asymmetries are less lateralized for language, faces, and bodies than their right-handed counterparts. These results are difficult to reconcile with current theories of language asymmetry or of handedness.

Indexed as

AdultBrainBrain MappingDominance, CerebralFacial RecognitionFemaleFunctional LateralityHumansLanguageLanguage TestsMagnetic Resonance ImagingMaleRecognition, PsychologyYoung Adultbrain asymmetryfMRIhandednessleft hemisphereright hemisphere

Identifiers

PMID33884412
PMCPMC8824548

What OpenQuestion holds

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LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.