Replication alert: behavioural lateralization in a detour test is not repeatable in fishes

Data for: Roche DG, Amcoff M, Morgan R, Sundin J, Andreassen AH, Finnøen MH, Lawrence MJ, Henderson E, Norin T, Speers-Roesch B, Brown C, Clark TD, Bshary R, Leungt B, Jutfelt F and Binning SA (in prep) Replication alert: behavioural lateralization in
a detour test is not repeatable in fishes
Please see the readme.txt file for metadata.
Abstract:

1. Behavioural
lateralisation, defined as the asymmetric expression of cognitive functions, is
reported to enhance key fitness-relevant traits such as group coordination, multitasking
and predator escape performance. Therefore, studies reporting negative effects on
lateralisation in fish due to environmental stressors such as ocean
acidification, hypoxia, and pollutants are worrisome. However, such studies tend
to use a detour test and focus on population-level measures, without validating
whether lateralisation measured using this method is consistent within individuals
across time.
2. We conducted
a multi-species, international assessment of the repeatability (R) of lateralisation in four previously
studied fish species (Ctenolabrus
rupestris, Danio rerio, Neopomacentrus azysron, and Pomacentrus amboinensis) using a detour
test (T-maze), a common method for testing lateralisation. We also re-analysed
a published dataset on guppies (Poecilia reticulata)
using new statistical methods. We expected the three shoaling species to
exhibit greater within-individual consistency in lateralisation than their
non-shoaling counterparts given previous reports of stronger lateralisation in
group-living fishes.
3. Absolute
and relative lateralisation scores were highly non-repeatable in all five species
(0.01<R<0.08), irrespective of their
shoaling status. We carefully reviewed 31 published studies in which the detour
test was employed to examine lateralisation in fish and identified statistical
issues in all of them. We develop and propose new statistical analyses to test
for population- and individual-level lateralisation (along with open code).

4. The
commonly used detour test does not appear to be an appropriate method for quantifying
behavioural lateralisation in fishes, calling into question functional inferences
drawn by many published studies, including our own. As a consequence, potential
fitness benefits of lateralisation and anthropogenic effects on lateralisation
as a proxy for adaptive brain functioning need to be assessed with alternative
paradigms.