Performance on a categorisation task suggests that removal of environmental enrichment induces ‘pessimism’ in captive European starlings (Sturnus vulgaris)

By Melissa Bateson, S. Matheson. Animal Welfare, 2007

229 citations recorded by the source corpus.

Improving the quality of life of captive animals is dependent on developing valid measures of how animals feel about their lives. It has recently been suggested that biases in information processing may offer a novel means of understanding animal emotions. Anxious and depressed people tend to interpret ambiguous information negatively. We explored the proposal that such cognitive biases also exist in non-human animals and could therefore be used as novel measures of animal welfare. We used a novel cognitive bias task based on a learnt taste aversion to determine whether birds deprived of environmental enrichment show biases in their classification of ambiguous signals. We hypothesised that starlings in enriched cages should be more likely to classify ambiguous signals as being associated with a positive outcome than starlings housed in standard, unenriched cages. Starlings were trained on a go/no-go procedure to discriminate between two visual stimuli (cardboard lids of white and dark grey) associated with outcomes of a different value (palatable and unpalatable mealworms hidden underneath). Individual birds' responses to unreinforced, intermediate stimuli (various shades of grey between white and dark grey) were subsequently examined while each bird was housed sequentially in both standard and enriched cages. The probability of a bird classifying an ambiguous pale grey lid as hiding a palatable mealworm was lower in standard cages than enriched cages, but this difference was found only in birds that received enriched cages first. Our results can be interpreted as showing a pessimistic bias in birds that have recently experienced a decline in environmental quality. These findings support the use of cognitive bias-based tasks as a novel, non-invasive technique for assessing welfare in non-human animals.

Subfields: Animal Science and Zoology, Genetics, Small Animals

View Paper: https://www.semanticscholar.org/paper/8f1810c6bd0e3ff080de2225678a0544a7216292

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Citations in the corpus

A spatial judgement task to determine background emotional state in laboratory rats, Rattus norvegicus (2008, background): “The prediction was that previous exposure to an enriched environment increases the negative consequences of being subsequently housed without enrichment, as indicated in previous research (e.g. Day et al., 2002; Latham & Mason, 2006; Bateson & Matheson, 2007).”
Larger, enriched cages are associated with 'optimistic' response biases in captive European starlings (Sturnus vulgaris) (2008, result): “This finding is supported by a recent demonstration that European starlings trained on a go/no-go foraging task also show increased pessimism in their judgement of ambiguous visual stimuli when environmental enrichment is removed from their cages (Bateson and Matheson, 2007).”
Release from restraint generates a positive judgement bias in sheep (2010, methodology): “, 2008), European starlings (Bateson and Matheson, 2007; Matheson et al., 2008), dogs, and Rhesus macaques (for review see Mendl et al.”
The Use of Judgement Bias to Assess Welfare in Farm Livestock (2015, methodology): “Almost all the studies that have investigated the effect of housing conditions on cognitive bias (Bateson & Matheson 2007; Douglas et al 2012), used a set-up of good or poor housing (enriched or not) with a prediction that animals in poor housing conditions would express negative responses to…”
Cognitive bias in a non-human primate: husbandry procedures influence cognitive indicators of psychological well-being in captive rhesus macaques (2012, methodology): “Bateson and Matheson (2007) found a 401 negative shift in cognitive bias among starlings moved from enriched to standard cages, but 402 no evidence for a positive shift in bias among birds moved from standard to enriched cages.”
Environmental enrichment induces optimistic cognitive bias in rats (2011, methodology): “In the ‘ Cheerio ’ (low-value reward) trial, the reward for a correct choice was half a Cheerio. number of possible probe trials run without inducing extinction (Bateson & Matheson 2007; Matheson et al. 2008).”
Relevance of brain and behavioural lateralization to animal welfare (2010, methodology): “Enrichment has also been shown to shift cognitive bias towards the positive in starlings tested on a task inwhich theywere trained to discriminate between bowls with a white and dark grey lids and were then tested with an intermediate shade of grey (Bateson and Matheson, 2007).”
Sheep exhibit a positive judgement bias and stress-induced hyperthermia following shearing (2011, unknown): “From these studies a pattern is becoming evident in which long-term stressors induce a negative judgement bias (Bateson and Matheson, 2007; Brilot et al., 2010; Burmanet al., 2008;Doyle et al., 2011;Harding et al., 2004).”
An integrative and functional framework for the study of animal emotion and mood (2010, background): “Recent studies of species including rats (Harding et al. 2004; Burman et al. 2008, 2009; Enkel et al. 2010), sheep (Doyle et al. 2010), starlings (Bateson & Matheson 2007; Matheson et al. 2008), rhesus monkeys and dogs (see Mendl et al. 2009 for a review) have found evidence in support of these…”