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Nonnutritive sucking: One of the major determinants of filial love
Author(s) -
ValLaillet David,
Nowak Raymond,
Giraud Sandra,
Tallet Céline,
Boivin Xavier
Publication year - 2006
Publication title -
developmental psychobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 93
eISSN - 1098-2302
pISSN - 0012-1630
DOI - 10.1002/dev.20142
Subject(s) - preference test , zoology , developmental psychology , psychology , test (biology) , preference , biology , mathematics , ecology , statistics
Abstract The present study investigated the rewarding effects of nonnutritive sucking on the development of a filial preference. Two experiments were conducted to test whether nonnutritive visceral and oral stimuli have reinforcing properties independent from each other or act in synergy. Lambs could interact freely with their dam but were deprived of suckling by covering the udder for the first 12 hr. In Experiment 1, suckling was prevented and replaced by human giving, in the presence of the mother, either a bottle of water (B 5 and B 2.5 : 5% or 2.5% birth weight, BW, divided into seven portions over 12 hr) or water via tube‐feeding (I 5 and I 2.5 : 5% or 2.5% BW, also divided into seven portions over 12 hr). During a two‐choice test performed at 12 hr after birth, only B 5 and I 5 lambs preferred their mother to an alien ewe however, B 5 were faster at choosing their mother at the beginning of the test. B 2.5 and I 2.5 lambs made a random choice. In Experiment 2, suckling was prevented and replaced by human giving, in the presence of the mother, either a bottle of water (B 2.5 : 2.5% BW, divided into seven portions over 12 hr) or water via tube‐feeding (I 10 and I 2.5 : 10% or 2.5% BW, also divided into seven portions over 12 hr). During a two‐choice test at 12 hr, tube‐fed lambs (I 10 and I 2.5 ) preferred their mother to a human. B 2.5 lambs were equally attracted to both partners and spent more time near the human than lambs from the other groups. In a test of reactivity to a human performed on neonates isolated from their mother, B 2.5 lambs explored the human much more than the other lambs. The presence of the human had soothing properties in B 2.5 lambs and once the human left, they were the only lambs displaying enhanced vocal and locomotor activity. In these experiments, nonnutritive gastrointestinal stimuli induced a preference for the mother whereas nonnutritive sucking led to a strong positive relationship with the human. These results suggest that when lambs suckle their dam, the development of filial bonding is facilitated through the combined effects of oral and gastrointestinal stimuli. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 220–232, 2006.