Valence and Intensity of Video Stimuli of Dogs and Conspecifics in Sheep: Approach-Avoidance, Operant Response, and Attention

Abstract

Simple SummaryAnimals’ judgement of stimuli’s negativity or positivity cannot always be assumed. To assess the valence and intensity of video stimuli (dogs as negative vs. conspecifics as positive stimuli) in sheep, we used three experimental approaches: (1) an approach-avoidance paradigm; (2) operant conditioning using the videos as reinforcers; and (3) an attention test. We measured sheep’s behavioral and physiological reactions. Sheep generally reacted to the videos presented. Nevertheless, we found no support with the approach–avoidance paradigm, and the attention test for dog videos were more negative than sheep videos. However, the operant conditioning indicated that sheep were more prone to avoid videos of moving dogs. Overall, we found that standard video images may not be ideal to represent valence characteristics of stimuli to sheep.AbstractStimuli are often presumed to be either negative or positive. However, animals’ judgement of their negativity or positivity cannot generally be assumed. A possibility to assess emotional states in animals elicited by stimuli is to investigate animal preferences and their motivation to gain access to these stimuli. This study’s aim was to assess the valence of social stimuli in sheep. We used silent videos of varying intensity of dogs as negative versus conspecifics as positive stimuli in three approaches: (1) an approach–avoidance paradigm; (2) operant conditioning using the video stimuli as reinforcers; and (3) an attention test. In the latter, we assessed differential attention of sheep to simultaneous projections by automatically tracking sheep head and ear postures and recording brain activity. With these approaches, it was difficult to support that the sheep’s reactions varied according to the stimuli’s presumed valence and intensity. The approach–avoidance paradigm and attention test did not support the assumption that dog videos were more negative than sheep videos, though sheep reacted to the stimuli presented. Results from the operant conditioning indicated that sheep were more prone to avoid videos of moving dogs. Overall, we found that standard video images may not be ideal to represent valence characteristics of stimuli to sheep.

Affect-Driven Attention Biases as Animal Welfare Indicators: Review and Methods

“…Negative-valence sheep spent longer oriented towards the stimuli overall, however, which may have been an ADAB to social information. A video-based preferential looking paradigm was also recently developed for sheep [ 53 ], although this study did not include an affect manipulation. Unlike in Vögeli et al, no significant differences were found between the positive (conspecifics) and negative stimuli (dogs).…”

“…Ruminants have a wide field of vision, for instance, rendering head orientation a potentially unreliable proxy for eye gaze. Instead, ear posture and movement signals affective state in several livestock species (e.g., cattle [ 185 , 186 ], sheep [ 53 , 187 , 188 , 189 ], goats [ 190 ], and pigs [ 191 ], Sus scrofa domesticus ), as well as dogs [ 192 ] and mice [ 193 ] ( Mus spicilegus ). A preferential hearing paradigm might replace the competing images with a positive-valence conspecific vocalization and a negative-valence predator vocalization.…”

Peer Review #2 of "The influence of pharmacologically-induced affective states on attention bias in sheep (v0.1)"

“…Further studies should be conducted to better understand how animals perceive and respond to the stimuli presented during attention bias tests. Such studies should not only consider the salience of the stimuli, but should also consider the type of stimuli used with regards to the primary sensory systems of the animals being tested (Raoult & Gygax, 2018, Winters et al, 2015.…”

Weak General but No Specific Habituation in Anticipating Stimuli of Presumed Negative and Positive Valence by Weaned Piglets

“…Nevertheless, a comparison of the direct reaction to the stimuli may be desirable, although the use of indicator variables may be more difficult then, given the fact that a variety of stimuli were used. Other approaches such as place conditioning [ 7 ] or operant procedures ([ 46 ], this volume) may then be needed.…”