title: A reappraisal of successive negative contrast in two populations of domestic dogs.
abstract: When an anticipated food reward is unexpectedly reduced in quality or quantity, many mammals show a successive negative contrast (SNC) effect, i.e. a reduction in instrumental or consummatory responses below the level shown by control animals that have only ever received the lower-value reward. SNC effects are believed to reflect an aversive emotional state, caused by the discrepancy between the expected and the actual reward. Furthermore, how animals respond to such discrepancy has been suggested to be a sign of animals' background mood state. However, the occurrence and interpretation of SNC effects are not unequivocal, and there is a relative lack of studies conducted outside of laboratory conditions. Here, we tested two populations of domestic dogs (24 owned pet dogs and 21 dogs from rescue kennels) in a SNC paradigm following the methodology by Bentosela et al. (J Comp Psychol 123:125-130, 2009), using a design that allowed a within-, as well as a between-, subjects analysis. We found no evidence of a SNC effect in either population using a within- or between-subjects design. Indeed, the within-subjects analysis revealed a reverse SNC effect, with subjects in the shifted condition showing a significantly higher level of response, even after they received an unexpected reduction in reward quality. Using a within-, rather than a between-, subjects design may be beneficial in studies of SNC due to higher sensitivity and statistical power; however, order effects on subject performance need to be considered. These results suggest that this particular SNC paradigm may not be sufficiently robust to replicate easily in a range of environmental contexts and populations.
authors.affiliation: Animal Behaviour, Cognition and Welfare Research Group, School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Beevor Street, Lincoln, LN6 7DL, UK.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Riemer
authors.affiliation: Animal Behaviour, Cognition and Welfare Research Group, School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Beevor Street, Lincoln, LN6 7DL, UK.
authors.forename: Sarah L H
authors.initials: SL
authors.lastname: Ellis
authors.affiliation: Animal Behaviour, Cognition and Welfare Research Group, School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Beevor Street, Lincoln, LN6 7DL, UK.
authors.forename: Sian
authors.initials: S
authors.lastname: Ryan
authors.affiliation: Animal Behaviour, Cognition and Welfare Research Group, School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Beevor Street, Lincoln, LN6 7DL, UK.
authors.forename: Hannah
authors.initials: H
authors.lastname: Thompson
authors.affiliation: Animal Behaviour, Cognition and Welfare Research Group, School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Beevor Street, Lincoln, LN6 7DL, UK. oburman@lincoln.ac.uk.
authors.forename: Oliver H P
authors.initials: OH
authors.lastname: Burman
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D003216:Conditioning, Operant / Q000502:physiology*; D004285:Dogs / Q000523:psychology*; D004644:Emotions / Q000502:physiology; D005247:Feeding Behavior; D005260:Female; D008297:Male; D057805:Pets; D012201:Reward
keywords: Affective state; Dog Canis familiaris; Environment; Food reward; Reward sensitivity; Successive negative contrast (SNC)