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Behaviour has a significant heritable component; however, unpicking the variants of interest in the neural circuits and molecular pathways that underpin these has proven difficult. Here, we present a comprehensive analysis of the relationship between known and new candidate genes from identified pathways and key behaviours for survival in 109 adult rhesus macaques (Macaca mulatta). Eight genes involved in emotion were analysed for variation at a total of nine loci. Genetic data were then correlated with cognitive and observational measures of behaviour associated with wellbeing and survival using MCMC-based Bayesian GLMM in R, to account for relatedness within the macaque population. For four loci the variants genotyped were length polymorphisms (SLC6A4 5-hydroxytryptamine transporter length-polymorphic repeat (5-HTTLPR), SLC6A4 STin polymorphism, Tryptophan 5-hydroxylase 2 (TPH2) and Monoamine oxidase A (MAOA)) whilst for the other five (5-hydroxytryptamine receptor 2A (HTR2A), Dopamine Receptor D4 (DRD4), Oxytocin receptor (OXTR), Arginine vasopressin receptor 1A (AVPR1a), Opioid receptor mu(μ) 1 (OPRM1)) SNPs were analysed. STin genotype, DRD4 haplotype and OXTR haplotype were significantly associated with the cognitive and observational measures of behaviour associated with wellbeing and survival. Genotype for 5-HTTLPR, STin and AVPR1a, and haplotype for HTR2A, DRD4 and OXTR were significantly associated with the duration of behaviours including fear and anxiety. Understanding the biological underpinnings of individual variation in negative emotion (e.g., fear and anxiety), together with their impact on social behaviour (e.g., social attention including vigilance for threat) has application for managing primate populations in the wild and captivity, as well as potential translational application for understanding of the genetic basis of emotions in humans. [ABSTRACT FROM AUTHOR]

• Attention bias is a new measure of animal emotion and welfare that requires validated tools. • Protocols are detailed and tested with a large sample of 109 monkeys. • Attention to threat reflects trait affect and attention bias is sensitive to shifts in emotion state. • Repeated testing and inter-trial interval impact results. • Effects of sex, stimuli used, time of day, previous experience and visual field were present. Attention bias is a new approach to assessing animal affect that has shown promising results in several animal species. It describes a tendency to preferentially attend to emotional compared to neutral cues and is influenced by underlying affect. It is important in the early days of this new field that we develop widely utilisable methods and incorporate lessons from the human literature from which tasks are adapted. This fundamental knowledge is critical to the development of standardised and sensitive tools, and the validation of experimental protocols to ensure best practice. Here, we describe protocols for two preferential-looking attention bias tasks. Study 1 involved a manual task using freely available low-cost materials. Study 2 used an automated task requiring specialist equipment and programming, but presumably less prone to noisy data. Tasks were tested with 109 socially housed rhesus macaques, Macaca mulatta, who had been trained to sit by a target, but received no other training. Tasks involved showing animals emotional face pairs (threat-neutral), and subsequent blind coding of video for duration of looking at either face. Three measures of social attention were examined: time spent looking at the threat face (THR), total time looking at the threat-neutral face pair overall (TL), and attention bias difference score (ABD) calculated as time spent looking at the neutral face subtracted from time spent looking at the threat face. Based on the human literature and early primate work, the influence of five potential confounding factors on attention was assessed: trial number, stimulus ID, previous testing experience, time of day and visual field to which the threat face was presented; as were several life history factors: sex, age, and social rank. Both tasks revealed stable individual differences in baseline social attention (THR and TL: effect sizes = 0.15−0.31; repeatabilities = 0.12−0.26; suggesting sensitivity to trait affect), but not ABD (which may be more sensitive to brief shifts in emotion state). All potential confounding factors had a significant effect on at least one measure of social attention. For a subset of monkeys who took part in both Study 1 and Study 2 several years apart (n = 18), there was significant reproducibility between tasks for all three measures (R = 0.15−0.63), supporting an argument for stable individual differences in baseline attention bias, and validating the two tasks for measuring the same trait. The attention bias method shows promise for further development of standardised protocols with animals. We provide framework and recommendations for future method development. [ABSTRACT FROM AUTHOR]