Measuring infant handedness reliably from reaching: A systematic review

ABSTRACT

Researchers have utilized reaching paradigms to measure infant handedness for more than a century. However, methods vary widely. Recent research has identified that the number of trials used in assessment is critical with the recommendation that at least 15 trials are necessary to reliably classify infants into handedness categories via statistical cutoffs. As a first step towards establishing best practices for the field, we identified, categorized, and synthesized findings according to trial number from studies that utilized reaching to index handedness in infants across the first two years of life using PRISMA guidelines. Database searches were conducted in PsycINFO, PubMed, and Ovid MEDLINE^®. All articles published through May 2018 were included. Additional records were identified through other sources. After removing duplicates, 1,116 records were screened using the online software program Abstrackr. Of these records, 125 full-text articles were further assessed for eligibility, and 87 articles were included in the qualitative synthesis. Results revealed that the majority of papers published since 1890 (70%) do not meet the 15-trial minimum criterion for statistically reliable measurement of infant handedness. Broad themes from articles meeting the measurement criterion and implications for future research are discussed.

KEYWORDS:

• Infant
• handedness
• hand preference
• laterality
• reaching

Acknowledgements

The authors thank Venus Betancourt for her early contribution to the project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work described in this report was supported by the National Institute of Child Health and Human Development (NICHD) under grant number R03HD09741901 to ELN. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health (NIH).