Study
Number-space mapping in the newborn chick resembles humans’ mental number line
Rugani, Rosa; Vallortigara, Giorgio; Priftis, Konstantinos; Regolin, Lucia
Science, 2015
Newly hatched chicks were familiarised with a target number of shapes, then offered two identical panels — one to the left and one to the right — each bearing a different quantity. Which panel they approached was recorded.
- Studied in
- Gallus gallus domesticus
- Sample size
- newly hatched chicks across several experimental groups
Chicks preferentially approached the left panel when it showed a quantity smaller than the familiar number, and the right panel when it showed a larger one.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
A left-to-right orientation of numerical magnitude is present in animals with no numerical education, suggesting it is not a product of reading or schooling.
How NatureHQ reads it
Interesting precisely because it separates two things usually bundled together. Humans map numbers onto space left-to-right, and it is easy to assume that comes from reading direction. A day-old chick that has never read anything showing the same bias suggests a deeper origin. What it does not show is that chicks count in any richer sense — the task is relative magnitude with a spatial choice, and that is all it measures.
- Demonstrates a spatial bias associated with magnitude, not counting or arithmetic.
- Directional biases in approach behaviour have several possible causes besides number.
- Findings in this area have prompted continuing methodological debate about controls for surface area and density.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: American Association for the Advancement of SciencePublished in Science or Science Advances (AAAS).
doi.org/10.1126/science.aaa1379
This reference was checked by an editor on 2026-08-09.
A note on this reference: Confirmed by direct DOI lookup rather than by search: the record appears in Crossref but not in OpenAlex search results, so the resolver held it below its two-register threshold.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.