ArticleScientific reports2019
Parrots do not show inequity aversion.
Article in Scientific reports, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers, 1 of them a synthesis that pooled it.
What it found
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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.
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.
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Who cites it
5 citing papers in PubMed, 1 synthesis or guideline pooled it, 8 citations in OpenAlex.
- No evidence for inequity aversion in non-human animals: a meta-analysis of accept/reject paradigms.Proceedings. Biological sciences · 2024Pooled it
- No Response to Inconsistently Experienced Inequity in Four Primate Species.American journal of primatology · 2026Article
- Recent developments in parrot cognition: a quadrennial update.Animal cognition · 2023Review
- No evidence for a relationship between breed cooperativeness and inequity aversion in dogs.PloS one · 2020Article
- Assessing African grey parrots' prosocial tendencies in a token choice paradigm.Royal Society open science · 2019Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Inequity aversion, the negative reaction to unequal treatment, is considered a mechanism for stabilizing cooperative interactions between non-kin group members. However, this might only be adaptive for species that switch cooperative partners. Utilizing a comparative approach, inequity aversion has been assessed in many mammalian species and recently also in corvids and one parrot species, kea, revealing mixed results. To broaden our knowledge about the phylogenetic distribution of inequity aversion, we tested four parrot species in the token exchange paradigm. We varied the quality of rewards delivered to dyads of birds, as well as the effort required to obtain a reward. Blue-headed macaws and African grey parrots showed no reaction to being rewarded unequally. The bigger macaws were less willing to exchange tokens in the "unequal" condition compared to the "equal high" condition in which both birds obtained high quality rewards, but a closer examination of the results and the findings from the control conditions reveal that inequity aversion does not account for it. None of the species responded to inequity in terms of effort. Parrots may not exhibit inequity aversion due to interdependence on their life-long partner and the high costs associated with finding a new partner.
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Registered trials
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.