Effects of stimulus novelty on gnawing and eating by rats.

Abstract

Novel stimuli within several sensory modalities are potent determinants of action. Research in primates, carnivores, and rodents has indicated the importance of novel visual, auditory, and somatic stimuli for behavioral arousal and orientation (Welker, 1961). Probably for theoretical reasons, there has been a tendency to emphasize the independence of such "stimulus motivation" from need-involved behavior such as eating. The results presented below encourage a conceptual reorientation in this respect by demonstrating an influence of novelty of both edible and "inedible" materials on the eating and gnawing behavior of rats. METHOD SubjectsThe 5s were 10 Sprague-Dawley male rats, S of which were ophthalmectomized under ether at 25 days of age to eliminate visual cues. All 10 were kept in individual cages (21 cm. by 21 cm. by SO cm.) and tested when they were between 77 and 197 days of age. MaterialsThe rats were presented with a variety of nutritive and nonnutritive materials. Two brands of standard food pellet-Rockland Rat Diet (Pellet A) and Purina laboratory chow (Pellet B)-were used as the basic food. The five nonnutritive substances offered were two types of rubber eraser, nontoxic colored wax crayons, chalk sticks, and Alphacel, a powdered cellulose. Granulated sucrose sugar cubes, Ry-Krisp wafers, Rockland dog pellets, Purina monkey chow pellets, and 1-cc pieces of coagulated chicken egg albumen were offered as nutritive solids, and tap, distilled, and 0.1% saccharin water as fluids. ProcedureThe basic presentation period for all materials was 6 consecutive days and the entire experiment consisted of 20 such periods run consecutively. Standard food pellets (Pellets A or B) were offered on every test day

The free food (contrafreeloading) phenomenon: A review and analysis

“…Adding stimulus feedback from a different stimulus modality, as Osborne and Shelby did, added no information to the situation, yet responding increased. This squares with the fact that increasing the complexity, the inconstancy, or the novelty of a sensory reinforcer increases its reinforcing potential (Barnes & Baron, 1961;Dember, 1956;Welker & King, 1962). Sensory reinforcement also may account for some of the differences in acquisition and maintenance of free-food responding between animals reared in different environments.…”

BITING ATTACK BY RATS IN RESPONSE TO AVERSIVE SHOCK1

“…Previous investigators have recorded the biting of rats by providing a block of wood which the rat could gnaw (Roberts and Carey, 1965;Welker and King, 1962). Unfortunately, that method did not permit a continuous recording of biting; the biting was indirectly measured by weighing the wood before and after a session and calculating how much had been removed (Welker and King, 1962).…”

“…Unfortunately, that method did not permit a continuous recording of biting; the biting was indirectly measured by weighing the wood before and after a session and calculating how much had been removed (Welker and King, 1962).…”

Wally Welker 1926–2007

“…Wally published behavioral observations of ''free ranging'' adult rats and rat pups (Welker 1957(Welker , 1958(Welker , 1959aWelker and King 1963). Theses studies, using slow frame speed filming (1 fps), eventually led Wally to re-examine the role of whiskers in rat behavior that he published in his classic article in the British journal Behaviour (Welker 1964).…”