Ž .
Applied Animal Behaviour Science 69 2000 149–168 www.elsevier.comrlocaterapplanim
Taste reactivity patterns in domestic cats ž
Felis silÕestris catus
Ruud Van den Bos , Margot K. Meijer, Berry M. Spruijt
Animal Welfare Centre, Utrecht UniÕersity, Yalelaan 17, NL-3584 CL Utrecht, Netherlands Accepted 9 March 2000
Abstract
Ž The present study is aimed at finding taste reactivity patterns in domestic cats Felis silÕestris
. catus which reflect ‘liking’ or perceived palatability. Three groups of nonstressed cats living in
households were formed which a priori were expected to differ in motivational state for eating Ž
. food items more or less hungry , and which were offered two different food items differing in
Ž .
general taste properties more or less flavourful food, MFF and LFF, respectively around the time that they were fed their normal food. Analysis of the amount of food eaten showed that MFF was
consumed regardless of hunger level and that LFF was consumed depending on the hunger level of cats: the more hungry cats ate more of LFF than the less hungry cats. Analysis of post-meal
behavioural sequences showed that the ‘MFF consumption sequence’ differed from the ‘LFF refusal sequence’ and that the ‘LFF consumption sequence’ strongly resembled the ‘MFF
consumption sequence’ but also contained elements of the ‘LFF refusal sequence’. Subsequent analysis of the frequencies and total durations of behavioural patterns showed that two kinds of
patterns existed, possibly reflecting two ‘palatability dimensions’: hedonic taste reactivity patterns Ž
. Ž
lickrsniff feeding bowl, lip lick and groom face and aversive taste reactivity patterns lickrsniff .
food and lick nose . These dimensions may be combined to obtain a single palatability score. q 2000 Elsevier Science B.V. All rights reserved.
Keywords: Cat; Palatability; Taste reactivity patterns; Welfare
1. Introduction
Ž .
Vertebrates possess a system to maintain the balance between positive ‘satisfaction’ Ž
. and negative
‘stress’ experiences to make efficient use of resources against the
Ž .
background of changing environmental conditions incentivesrstressors and changing
Corresponding author. Tel.: q31-30-2534-373; fax: q31-30-2539-227. Ž
. E-mail address: r.vandenboslas.vet.uu.nl R. Van den Bos .
0168-1591r00r - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž
. PII: S 0 1 6 8 - 1 5 9 1 0 0 0 0 1 2 4 - 6
internal physiological conditions, and to estimate costs and benefits prior to taking Ž
. action Spruijt et al., 2000; Mason et al., 1997 . The reward system, supporting the
‘satisfaction-component’ of this system, consists of two parts which can be sepa- Ž
rated conceptually, neurobiologically and behaviourally Berridge, 1996; Berridge and .
Robinson, 1998; Fraser and Duncan, 1998; Spruijt et al., 2000 : one part, which deals Ž
. with the immediate appreciation of commodities likingrdisliking , and one part which
Ž .
deals with the disposition to act upon this appraisal in future wanting . It should be noted that ‘liking’ and ‘wanting’ do not point to self-conscious or second-order
intentional processes but rather to first-order intentional or goal-directed processes ŽBerridge and Robinson, 1998; Van den Bos, 1997, 2000; Dickinson and Balleine, 1994;
. Heyes and Dickinson, 1990 .
The present study concentrated solely on the immediate appreciation of a commodity itself. This appraisal is determined after the commodity’s ‘consumption’ and dependent
on several factors such as motivational state, previous experience and general properties Ž
. of the commodity Grill and Berridge, 1985 . The commodity in this study is food. As
Ž .
Ž .
shown in rats, the incentive value ‘liking’ or perceived palatability of food items can be measured by the occurrence of discrete behavioural patterns, i.e. taste reactivity
patterns: ‘‘taste reactivity patterns must be regarded as true affective reactions, which Ž
connote core processes of affective ‘liking’ versus ‘disliking’’’ italics in the original text omitted; Berridge, 1996; Berridge and Robinson, 1998, p. 355; Grill and Berridge,
. 1985; Grill and Norgren, 1978 . More specifically, it has been shown that two types of
Ž .
sequences of patterns exist: hedonic patterns and aversive patterns. These have been obtained by analysing the rats’ behaviour after forced intra-oral infusion of solutions,
Ž .
Ž .
Ž which were subsequently ingested e.g. sucrose solution or rejected e.g. quinine
. solution . It has been shown that the expression of these patterns is affected by the
motivational state of the animals, such as revealed by manipulating the deprivational state of animals, and the previous experiences with food items, such as revealed by the
Ž .
conditioned taste aversion paradigm Grill and Berridge, 1985 . For instance, it has been Ž
. shown that as animals are or become satiated, less hedonic and more aversive taste
reactivity patterns to the same stimulus are shown, suggesting a change in ‘liking’ or Ž
perceived palatability Grill and Berridge, 1985, p. 16; Cabanac and Lafrance, 1990, .
Ž .
1991, 1992; Berridge, 1991 . Cabanac 1971, 1979, 1992 observed the same phe- nomenon in humans, using verbal ratings of pleasantness in response to stimuli, and
labelled it alliesthesia: ‘a given stimulus can induce a pleasant or unpleasant sensation Ž
depending on the subject’s internal state’ Cabanac, 1971, p. 1107; Berridge, 1996, p. 2, .
1991, p. 103 . To study such patterns in cats, therefore, different groups of cats were studied which
Ž .
had different motivational states more or less hungry and received two different food Ž
. items more or less flavourful under the following hypothesis: palatability is dependent
Ž Ž
. on general features of the food item external: more flaÕourful food MFF than average
Ž .
. or less flaÕourful food LFF than average and the motivational state of the cats
Ž .
internal: more or less hungry . The hungrier the cats the more likely they will eat LFF and the more they will show the behavioural patterns which normally belong to MFF.
Conversely, the less hungry the cats the less likely they will eat LFF and the more they will show behavioural patterns which normally belong to LFF.
2. Materials and methods
