On the Validity of a Single (Boldness) Assay in Personality Research

Abstract

A common method to assess behavioral types in personality research involves the use of a single emergence test (employed by researchers working on fish, avian, mammal, amphibian, and invertebrate taxa), whereby a shorter latency to emerge from a holding container into a novel environment is inferred to represent greater ‘boldness’. Although any behavior might be context specific, studies using this single assay type must assume it reflects boldness in other similar contexts, otherwise it cannot reflect personality (defined as consistency across time and/or contexts). We attempted to validate whether a single assay of this type is correlated with other similar assays of boldness under more familiar, and less stressful, situations. We compared single emergence test scores of two species of damselfish (Pomacentrus wardi; P. amboinensis) in a novel environment, with two different behavioral assays of the same fish in subsequent repeated trials in home tanks. Although behavior was highly repeatable in home tanks, we found no correlation between emergence test scores in the novel environment and measures of latency to emerge from shelter following disturbance, or activity levels, on the first, second, or third observations in home tanks; there was also no correlation when we used average home tank scores from mixed models that accounted for individual differences (i.e., plasticity) in the rate of habituation (latency) and acclimation (activity). Our results therefore lead us to question the validity of using this single emergence test assay as a predictor of general boldness and to question the use of any single assay of behavior in personality research.

Island tameness and the repeatability of flight initiation distance in a large herbivore

“…Although consistent with results from a study of FID in semiferal Welsh Mountain ponies (Birke et al 2011), this result is nonetheless surprising given that short-term desensitization has been documented for a number of behavioural assays (e.g., Bell et al 2009;Beckmann and Biro 2013) and is widely assumed to occur for FID (Rodríguez-Prieto et al 2009). In contrast, there are two lines of evidence for long-term habituation to people.…”

“…We aimed to determine if FID is a repeatable trait with the potential to form the basis of future research on the evolution and maintenance of risk aversion and island tameness. Because animals are known to habituate (become desensitized) to behavioural assays (e.g., Beckmann and Biro 2013) and generally assumed to occur for FID (Rodríguez-Prieto et al 2009), we tested if FID decreased over successive measurements made on the same day or on successive days. In addition, because risk-taking can vary between the sexes (Samia et al 2015), we tested if FID varied between males and females.…”

Group personality during collective decision-making: a multi-level approach

“…The study of animal personalities generally seeks to understand how and why individuals maintain personalities, as well as their ecological and evolutionary implications [33,55]. We have shown that the probability of reaching consensus in a patchy environment does not vary between groups and is independent of the distributions of personalities within groups.…”

Demystifying animal ‘personality’ (or not): why individual variation matters to experimental biologists

“…construct validity; Carter et al, 2013, Koski, 2014, researchers must also consider whether the design of the test and the behaviours measured are ecologically relevant for the species of interest (i.e. ecological validity; Réale et al, 2007;Beckmann and Biro, 2013;Koski, 2014). This is especially true when trying to understand the life-history implications or fitness outcomes associated with a particular behaviour and when comparing studies.…”