Once an optimist, always an optimist? Studying cognitive judgment bias in mice

This repository contains raw data and analysis code for the manuscript entitled \"Once an Optimist, Always an Optimist? Studying Cognitive Judgment Bias in Mice\" from Marko Bračić, Lena Bohn, Viktoria Siewert, Vanessa von Kortzfleisch, Holger Schielzeth, Sylvia Kaiser, Norbert Sachser, S. Helene Richter, accepted for publication in the journal Behavioral Ecology.
The aim of the study was to investigate the causes and stability of cognitive judgment bias (aka \"optimism\").
Individuals differ in the way they judge ambiguous information: some individuals interpret ambiguous information in a more optimistic, and others in a more pessimistic way. Over the past two decades, such “optimistic” and “pessimistic” cognitive judgement biases (CJBs) have been utilized in animal welfare science as indicators of animals’ emotional states. However, empirical studies on their ecological and evolutionary relevance are still lacking.
We, therefore, aimed at transferring the concept of “optimism” and “pessim..., The experiment lasted for one year (February 2019 – March 2020) and was conducted in two independent batches. Laboratory mice were obtained from a professional breeder at the age of four weeks and housed at the University of Münster. We housed female mice of two strains/genotypes (C57BL/6J and B6D2F1N) in two environmental conditions: a “scarce environment” and a “complex environment”. Mice were housed in same-strain groups of three individuals per cage. To allow for individual identification within cages, all mice received partial ear punches (earcut) upon arrival. The three mice housed in the same cage were exposed to the same environmental conditions but participated in different sets of the following experimental phases: a touchscreen training phase (TS), first cognitive judgement bias (CJB) test phase, repeated CJB testing phase, and behavioral test phase.
One mouse from each cage was touchscreen trained and tested in the first CJB test phase before it was removed from the cage to ..., Variables in the dataset are explained in the ReadMe file and further clarified in the methods above (variables marked bold). Due to a setup error in the labyrinth maze (LM), three mice had to be excluded from the (labyrinth maze) analysis (NA).
For the analysis of each dataset, a separate R script is provided. To successfully run the R script, make sure that the data files are in R working directory (e.g. keep data and script in the same folder or change the working directory to the folder where data is saved) and that listed R packages are installed.