‘Personality’ has been a big topic in behavioural ecology for well over a decade now, and work is still coming thick and fast showing that individual animals can show consistent sets of correlated behaviours in different situations, and that that different individuals can show different sets of these behaviours. For example, many different species have been shown to have some individuals who are ‘bold’ risk-takers who are active in their response to stimuli, whilst other ‘shy’ individuals are less likely to take risks, and will be passive in their response.
However, when groups of individuals come together to behave in a social setting, it could be the case that these consistent personalities break down, as it may not be possible or suitable for every individual to follow their own personality-defined behaviour. A recent paper in Science Advances from Christos Ioannou’s group (McDonald et al. 2016), that I was privileged to be involved with, demonstrates just this. The study looked at what happens when you put together groups of sticklebacks that have different personalities.
By testing the fish individually, we showed that there was consistency in how they emerged from a safe shelter and travelled through a ‘dangerous’ exposed area of water in order to reach a foraging site: some individuals were bolder than others. However, when you put groups together with a range of bold and shy individuals, the shy individuals tended to lose their shyness and behave in a similar way to the bold individuals. This effect is only temporary – once the fish became used to the test conditions and their groups, they reverted to their initial personality-defined behaviours.
This study suggests that personality isn’t necessarily consistent in individuals, and may well depend upon context. Being able to remain in a group is very likely to be important for sticklebacks, and it makes sense that shy individuals will mask their behaviour in order to maintain the protection of a group. Whether this is ignoring the behaviour determined by their own personality, or rather another aspect of their personality that is defined by social context or some other aspect of state (see Dall et al. 2004 for discussion), it suggests that there is a lot more to be explored concerning how personalities are affected by groups.
Dall SRX, Houston AI & McNamara JM (2004). The behavioural ecology of personality: consistent individual differences from an adaptive perspective. Ecology Letters 7: 734-739 | abstract
McDonald ND, Rands SA, Hill F, Elder C & Ioannou CC (2016). Consensus and experience trump leadership, suppressing individual personality during social foraging. Science Advances 2: e1600892 | full text (open access) | pdf | blog posting from Christos Ioannou