Losing aggressive contests may impact survival, reproductive success and animal welfare. Previous experience plays an important role in shaping contest behaviour, but less is known about how individual variation in learning abilities influences contest dynamics and resource-holding potential. Here, we investigated whether learning performance (acquisition learning and reversal learning) in domestic pigs, Sus scrofa, predicts the outcome of a contest against an unfamiliar opponent. While acquisition learning speed did not predict contest outcome, pigs that successfully learned the reversal were more likely to win the contest than pigs that failed to learn the reversal. As expected, weight difference between opponents was also an important factor in predicting contest outcome. Our results suggest that cognitive flexibility may confer an advantage in contests, unless pigs already have a substantial weight advantage over their opponent. These findings advance our understanding of the role of cognitive processes in animal contests and suggest that promoting cognitive flexibility may reduce the potential welfare impacts arising from stressful social defeat. Further research is required to determine whether cognitive flexibility influences assessment strategy and allows pigs to resolve contests with fewer costs. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).

Overall, I find this to be a good quality and enjoyable article to read. The model allows new hypotheses to be tested, such as the effects of availability of uncontested resources and of dominant monopolisation of reproduction on learning (winner-loser effects). However, the justification for this study in the introduction is weak and I had to re-read several sections to know what the independent and dependent variables were. I do not have experience of generating behavioural models, so cannot comment on the validity of your results, however having related interests in applied animal behaviour, I would have appreciated more clear presentation of results. To encourage collaboration, I suggest revising the abstract and introduction in order to clearly outline the need for such a model, and to ease the understanding of your results by readers from adjacent fields, to avoid overuse of acronyms and to explain your key terms more explicitly throughout. Please find comments on individual lines below: Abstract You describe your main findings well, but here the justification and application of the study could be briefly outlined in order to engage a wider audience. The second sentence does not make it clear what you are really testing. You don’t test the link between access to resources and reproductive skew, as I understood it, what you really test is the effect of different types of dominance structure and the cost of fighting, and the effects of dominance structure on winner-loser effects. compare results…”,

Aggression between unfamiliar commercial pigs is common and likely invokes strong emotions in contestants. Furthermore, contest outcomes affect subsequent aggressive behaviour, suggesting a potential lasting influence on affective state. Here we used a combination of qualitative and quantitative methods to assess the emotional expression of pigs in agonistic encounters. We investigated how recent victory or defeat influences emotions expressed in a subsequent contest, and the role of aggressiveness as a personality trait in emotional expression. We observed the pre-escalation contest behaviour (second contest; age 13 wks) in animals of different aggressiveness (categorised using two resident intruder tests as Agg+ or Agg-, age 9 wks), which had recently won or lost a contest (first contest; 10 wks). We measured gaze direction and ear position. Observers watched video clips of the initial 30 s of the second contest and evaluated the emotional expression of 57 pigs (25 contest 1 winners, 32 contest 1 losers) using qualitative behavioural assessment (QBA) with a fixed list of 20 descriptive terms. QBA identified three principal components (PCs), accounting for 68% of the variation: PC1 (agitated/tense to relaxed/content), PC2 (fearful/aimless to confident/enjoying) and PC3 (listless/ indifferent). Agg- pigs and males showed a more positive emotionality (PC2). PC1 and PC3 were unaffected by first contest outcome and aggressiveness. Agg+ pigs were more likely to hold their ears back (X2 =7.8, p = 0.005) during the early contest period. Differences in attention were detected in the contest outcome × aggressiveness interaction (χ24.3, p = 0.04), whereby approaching the opponent was influenced by winning and losing in the Agg- pigs only. QBA and gaze behaviour reveal differences in emotional valence between pigs of different aggressiveness: less aggressive pigs may be more susceptible to the emotional impact of victory and defeat but overall, more aggressive pigs express more negative emotionality at the start of agonistic encounters.

Contest behaviour, and in particular the propensity to attack an unfamiliar conspecific, is influenced by an individual’s aggressiveness, as well as by experience of winning and losing (so called ‘winner–loser effects’). Individuals vary in aggressiveness and susceptibility to winner–loser effects but the relationship between these drivers of contest behaviour has been poorly investigated. Here we hypothesise that the winner–loser effect on initiation of agonistic behaviour (display, non-damaging aggression, biting and mutual fighting) is influenced by aggressiveness. Pigs (n = 255) were assayed for aggressiveness (tendency to attack in resident−intruder tests) and then experienced two dyadic contests (age 10 and 13 weeks). Agonistic behaviour, up to reciprocal fighting, in contest 2 was compared between individuals of different aggressiveness in the RI test and experiences of victory or defeat in contest 1. Winner–loser effects were more influential than aggressiveness in determining initiation of agonistic behaviour. After accruing more skin lesions in contest 1, individuals were less likely to engage in escalated aggression in contest 2. The interaction between aggressiveness and winner–loser experience did not influence contest behaviour. The results suggest that aggressiveness does not compromise learning from recent contest experience and that reducing aggressiveness is unlikely to affect how animals experience winning and losing.

Emotions encompass cognitive and behavioural responses to reward and punishment. Using contests as a case-study, we propose that short-term emotions underpin animals' assessments, decision-making and behaviour. Equating contest assessments to emotional 'appraisals', we describe how contestants appraise more than resource value and outcome probability. These appraisals elicit the cognition, drive and neurophysiology that governs aggressive behaviour. We discuss how recent contest outcomes induce long-term moods, which impact subsequent contest behaviour. Finally, we distinguish between integral (objectively relevant) and incidental (objectively irrelevant) emotions and moods (affective states). Unlike existing ecological models, our approach predicts that incidental events influence contest dynamics, and that contests become incidental influences themselves, potentially causing maladaptive decision-making. As affective states cross contexts, a more holistic ethology (incorporating emotions and moods) would illuminate animal cognition and behaviour.