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The Way Humans Behave Modulates the Emotional State of Piglets.

Brajon S, Laforest JP, Schmitt O, Devillers N - PLoS ONE (2015)

Bottom Line: Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray).The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10).However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Agriculture and Agri-Food Canada, Dairy and Swine Research and Development Centre, 2000 College Street, Sherbrooke, Quebec, J1M 0C8, Canada; Université Laval, Department of Animal Science, 2325 Rue de l'Université, Quebec city, Quebec, G1V 0A6, Canada.

ABSTRACT
The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them.

No MeSH data available.


Related in: MedlinePlus

Percentages of time spent inside the apparatus and in contact with the trough are affected by the presence of a human observer, and to a lesser extent, by treatments.(A) Average percentage of time spent inside the apparatus and; (B) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests for piglets from gentle (GEN, light grey squares), rough (ROU, black triangles) and minimal contact (MIN, dark grey diamonds) treatments, regardless of the presence or not of the handler; (C) Average percentage of time spent inside the apparatus and; (D) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests in the absence (white circles) or presence (black circles) of the human observer, regardless of the treatment. (back-transformed least square means; P, positive cue; AP, ambiguous cue nearest positive cue; AM, ambiguous median cue; AN, ambiguous cue nearest negative cue; N, negative cue) (*** P < 0.0001).
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pone.0133408.g003: Percentages of time spent inside the apparatus and in contact with the trough are affected by the presence of a human observer, and to a lesser extent, by treatments.(A) Average percentage of time spent inside the apparatus and; (B) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests for piglets from gentle (GEN, light grey squares), rough (ROU, black triangles) and minimal contact (MIN, dark grey diamonds) treatments, regardless of the presence or not of the handler; (C) Average percentage of time spent inside the apparatus and; (D) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests in the absence (white circles) or presence (black circles) of the human observer, regardless of the treatment. (back-transformed least square means; P, positive cue; AP, ambiguous cue nearest positive cue; AM, ambiguous median cue; AN, ambiguous cue nearest negative cue; N, negative cue) (*** P < 0.0001).

Mentions: The Table 1shows an effect of the interaction between cue and treatment on the percentage of time spent inside the apparatus and in contact with the trough, meaning that changes in the approach behaviour of piglets from P to N cues progressed differently according to the treatment (Fig 3A and 3B). Indeed, the decrease of the approach behaviour from positive to negative cues of GEN piglets seems to be less pronounced than for MIN piglets. However, the analysis for each cue separately did not show any treatment effect.


The Way Humans Behave Modulates the Emotional State of Piglets.

Brajon S, Laforest JP, Schmitt O, Devillers N - PLoS ONE (2015)

Percentages of time spent inside the apparatus and in contact with the trough are affected by the presence of a human observer, and to a lesser extent, by treatments.(A) Average percentage of time spent inside the apparatus and; (B) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests for piglets from gentle (GEN, light grey squares), rough (ROU, black triangles) and minimal contact (MIN, dark grey diamonds) treatments, regardless of the presence or not of the handler; (C) Average percentage of time spent inside the apparatus and; (D) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests in the absence (white circles) or presence (black circles) of the human observer, regardless of the treatment. (back-transformed least square means; P, positive cue; AP, ambiguous cue nearest positive cue; AM, ambiguous median cue; AN, ambiguous cue nearest negative cue; N, negative cue) (*** P < 0.0001).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526664&req=5

pone.0133408.g003: Percentages of time spent inside the apparatus and in contact with the trough are affected by the presence of a human observer, and to a lesser extent, by treatments.(A) Average percentage of time spent inside the apparatus and; (B) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests for piglets from gentle (GEN, light grey squares), rough (ROU, black triangles) and minimal contact (MIN, dark grey diamonds) treatments, regardless of the presence or not of the handler; (C) Average percentage of time spent inside the apparatus and; (D) Average percentage of time spent in physical contact with the trough following playbacks of the five cues during cognitive bias tests in the absence (white circles) or presence (black circles) of the human observer, regardless of the treatment. (back-transformed least square means; P, positive cue; AP, ambiguous cue nearest positive cue; AM, ambiguous median cue; AN, ambiguous cue nearest negative cue; N, negative cue) (*** P < 0.0001).
Mentions: The Table 1shows an effect of the interaction between cue and treatment on the percentage of time spent inside the apparatus and in contact with the trough, meaning that changes in the approach behaviour of piglets from P to N cues progressed differently according to the treatment (Fig 3A and 3B). Indeed, the decrease of the approach behaviour from positive to negative cues of GEN piglets seems to be less pronounced than for MIN piglets. However, the analysis for each cue separately did not show any treatment effect.

Bottom Line: Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray).The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10).However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Agriculture and Agri-Food Canada, Dairy and Swine Research and Development Centre, 2000 College Street, Sherbrooke, Quebec, J1M 0C8, Canada; Université Laval, Department of Animal Science, 2325 Rue de l'Université, Quebec city, Quebec, G1V 0A6, Canada.

ABSTRACT
The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them.

No MeSH data available.


Related in: MedlinePlus