Social status and personality: stability in social state can promote consistency of behavioural responses

Abstract

Stability of 'state' has been suggested as an underlying factor explaining behavioural stability and animal personality (i.e. variation among, and consistency within individuals in behavioural responses), but the possibility that stable social relationships represent such states remains unexplored. Here, we investigated the influence of social status on the expression and consistency of behaviours by experimentally changing social status between repeated personality assays. We used male domestic fowl (Gallus gallus domesticus), a social species that forms relatively stable dominance hierarchies, and showed that behavioural responses were strongly affected by social status, but also by individual characteristics. The level of vigilance, activity and exploration changed with social status, whereas boldness appeared as a stable individual property, independent of status. Furthermore, variation in vocalization predicted future social status, indicating that individual behaviours can both be a predictor and a consequence of social status, depending on the aspect in focus. Our results illustrate that social states contribute to both variation and stability in behavioural responses, and should therefore be taken into account when investigating and interpreting variation in personality.

Keywords: behavioural syndromes; chicken; intra-sexual selection; phenotypic plasticity; social dominance.

Figure 1.

Behavioural response of dominant and subordinate males in the first trial of a novel arena test. Dominant males (‘dom’, filled circles) (a) tended to be bolder (i.e. more often entered the arena within 30 s), (b) were more vigilant (i.e. had higher frequency of time spent being vigilant), (c) were more active (i.e. performed more subarea transitions), (d) tended to be more explorative (i.e. visited more subareas), and (e) crowed more often (i.e. number of crows) compared with subordinate males (‘sub’, open circles; table 1). Values are given as untransformed mean±95% confidence interval (CI), except for (a), where the proportion of bold males±95% CI, are given.

Figure 2.

The effect of current social status (in trial 2) and previous behavioural responses (in the first novel arena test, i.e. ‘trial 1’) on the responses of male fowl in a novel arena test after social status was manipulated (i.e. ‘trial 2’). (a) Status in trial 2 (dominant males: filled circles, subdominant males: open circles) did not affect the proportion of males that were bold (i.e. males that entered the arena within 30 s), but previous boldness (x-axis) had a significant effect on boldness in trial 2 (y-axis). Males that were dominant in trial 2 (filled circles, solid line) were (b) more vigilant (i.e. had a higher frequency of time spent being vigilant), (c) more active (i.e. conducted more subarea transitions), and (d) more explorative (i.e. visited more subareas) compared with males that were subdominant (open circles, dashed line). At the same time, these behaviours were repeatable within individuals (demonstrated by a positive slope; table 2). (e) Social status in trial 2 did not affect crowing. The figures show transformed response variables (for transformations, see main text).

Figure 3.

Vigilance of male fowl of different social status during the first (trial 1) and second test trial (trial 2) in a repeated novel arena test. Dominant males (filled circles) were more vigilant (i.e. frequency of time spent being vigilant) compared with subordinate males (open circles). Current social status affected this behaviour, such that males who changed social status also changed the time spent being vigilant (dashed lines), whereas males with the same status during both trials were more consistent in their frequency of vigilance. Values presented are mean ± 95% CI. See the electronic supplementary material for similar figures for other behaviours (figure S2).