Testing domain general learning in an Australian lizard
A key question in cognition is whether animals that are proficient in a specific cognitive domain (domain specific hypothesis), such as spatial learning, are also proficient in other domains (domain general hypothesis) or whether there is a trade-off. Studies testing among these hypotheses are biased towards mammals and birds. To understand constraints on the evolution of cognition more generally, we need broader taxonomic and phylogenetic coverage. We used Australian eastern water skinks (Eulamprus quoyii) with known spatial learning ability in three additional tasks: an instrumental and two discrimination tasks. Under domain specific learning we predicted that lizards that were good at spatial learning would perform less well in the discrimination tasks. Conversely, we predicted that lizards that did not meet our criterion for spatial learning would likewise perform better in discrimination tasks. Lizards with domain general learning should perform approximately equally well (or poorly) in these tasks. Lizards classified as spatial learners performed no differently to non-spatial learners in both the instrumental and discrimination learning tasks. Nevertheless, lizards were proficient in all tasks. Our results reveal two patterns: domain general learning in spatial learners and domain specific learning in non-spatial learners. We suggest that delineating learning into domain general and domain specific may be overly simplistic and we need to instead focus on individual variation in learning ability, which ultimately, is likely to play a key role in fitness. These results, in combination with previously published work on this species, suggests that this species has behavioral flexibility because they are competent across multiple cognitive domains and are capable of reversal learning.
KeywordsDiscrimination task Eulamprus quoyii Instrumental task Reptile Spatial learning
This study was funded by the National Natural Science Foundation of China (31572273) to YQ, a Talent Reward Grant from the Sichuan provincial government (Y1D3011) to JF, and funding from Macquarie University to MJW.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest regarding this study.
This work was approved by the Animal Ethics Committee at Macquarie University (ARA2011/018) and lizards were collected under a permit from the Wildlife Licensing and Management Unit, Office of Environment and Heritage of New South Wales (scientific collection permit S13150).
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