Rescuing the baby from the bathwater: a reply to Carter (2013)

Abstract

Carter [1] identifies putative conceptual and methodological flaws in a paper from our laboratory on the effects of the social environment on explorationavoidance behaviour in a cichlid fish [2]. Although we welcome discussion of methodological issues that fosters the use of more solid experimental designs in personality research and we acknowledge that the experimental design used can be further improved, we disagree that the issues raised call into question the main conclusions of the target paper. Below, we reply to the problems identified by the author.Problem 1: what is the validity of the exploration/neophobia measures used?First, the author interprets the reported lack of consistency of the exploration/ neophobia results across different social contexts as indicative of lack of validity within a single context. Although we fully agree that within-context behavioural consistency (i.e. repeatability) is central to the definition of personality and to the validity of any personality test, we do not see how the lack of consistency across contexts can be interpreted per se as indicative of lack of consistency withincontexts and therefore question the validity of the novel object (NO) test used. Given that the social context has been manipulated in the target paper [2], we consider that the most parsimonious explanation (but not necessarily the correct one) for the lack of across-contexts consistency is that the manipulation of the independent variable (social context) induced the variation in the dependent variable (exploration/neophobia) in a differential way and that this caused the interaction effect that the lack of correlations across social contexts suggests. In our view, only the measurement of within-context consistency could clarify the point raised by the author, which unfortunately was not measured in the original study [2], based on the assumption of NO tests having high repeatability. This assumption was based on the wide use of the NO test in animal personality research and on available data for other cichlid species [3] that suggests a high within-context consistency of NO test measures in the short-term for this taxon. Thus, it is this assumption (and not the lack of between context consistency) that should be questioned, and in this regard we second Carter's view that within-context consistency should always be verified in animal personality studies. This is certainly an aspect to improve in future studies.Second, the author claims that novelty, a key aspect of the face validity of any exploration -avoidance test, is compromised, because the animals were exposed three times to the same NO, suggesting that a more appropriate procedure would have been the use of different objects in successive NO exposures. Indeed, this is a common procedure in animal personality research [3]. However, this procedure raises other methodological problems that are seldom discussed and that have to do with the need to control for variation in the valence and salience of the NOs used and their functional value to the

Shyness–Boldness, but not Exploration, Predicts Glucocorticoid Stress Response in Richardson's Ground Squirrels (Urocitellus richardsonii)

“…presence of humans, weather conditions, recent encounters with conspecifics or allospecifics). Thus, subsequent trials were not true ‘novel’ object trials (Carter ), but quantified average response over a series of presentations allowing an equal probability of habituation among subjects, while avoiding confounds associated with differential response to different novel objects (Heyser & Chemero ; Oliveira & Galhardo ).…”