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L W Kaufman

Publications and source records attributed to L W Kaufman.

13 recordsLinked to original sources
PubMed1986

The economics of the law of effect.

A corollary of the law of effect predicts that the larger the reinforcement, the greater the rate of responding. However, an animal must eat more small portions than large portions to obtain the same daily intake, and one would predict, therefore, that when eating smaller portions an efficient animal would eat less (conserving time and energy) and/or respond faster (conserving time). The latter of these predictions was supported by the present experiments with free-feeding rats for which portion size (pellet size or duration of feeder presentation) and portion price within meals were varied. Response rate was a function of the unit price (responses/g) of food: Rats responded faster when portions were smaller or when prices were higher. Meal size and frequency were relatively unaffected by unit price, but were influenced by the price of meal initiation. The results are discussed in relation to the economic differences between traditional operant and free-feeding paradigms and to both traditional and more recent formulations of the law of effect.

Animals↗
PubMed1983

Cost and meal patterns in wild-caught rats.

The effect of domestication upon behavior is not clearly understood and thus generalizations from domesticated laboratory animals to nondomesticated animals must be made with caution. Laboratory free-feeding studies with a variety of domesticated species have demonstrated that these animals reduce meal frequency and increase meal size as the cost of procuring access to food increases. The present experiment was conducted to determine if the same relations would be obtained with wild-caught rats. The results showed that laboratory-tested, wild-caught rats respond to changes in the cost of obtaining food in the same manner as domesticated rats. Wild-caught rats did, however, take longer to train and were less efficient than domesticated rats have proven to be in earlier research. In general, the results affirm the validity of laboratory simulations as a means of exploring parameters associated with foraging in natural settings.

Animals↗
PubMed1980

The critical cues for diurnal death feigning in young chicks: a functional analysis.

The critical determinants of extended diurnal death feigning were assessed in a refinement experiment in which visual and tactile cues during rearing and/or testing were systematically eliminated. Ninety-five domestic chicks were reared in either a social environment or physical (tactile) isolation, and half in each rearing condition were reared and/or tested under conditions of visual restriction. As expected, social rearing was prerequisite to the manifestation of extended death feigning; however, the incidence and duration of death-feigning was attenuated by functional visual isolation of socially reared chicks during either rearing or testing. It was concluded that visual novelty of the environment is the minimal condition for sustained death feigning by young chicks in the daylight hours.

Animals↗
PubMed1977

Components of predation defense behavior in chickens: evidence for endogenous rhythmicity.

The manifestation of diurnal periodicity and the extent of its control by the photoperiod was assessed in three predation defense reactions which constitute either components or outcomes of a predator-prey interaction sequence. Two-hundred White Leghorn chicks were reared from hatching for one week in either 24L or 12L and then tested at one of two clock hours previously demonstrated to define peak and trough response for one of the components. Putative evidence was found for an endogenous source of the periodicity manifested in all reactions. Maintenance schedule did not entrain the periodicity, but simple room entry and handling elicited anti-predator reactions, the extent of which varied as a function of clock hour. A general model of predation defense behavior was proposed.

Animals↗
PubMed1976

Duration of early visual experience and visual cliff behavior of chicks.

Visual cliff behavior was studied in 120 chicks as a function of 22, 46, 70, 94, or 118 hr of rearing in a deep or shallow environment. Preference for the deep side of the visual cliff increased directly with duration of depth-rearing but was uninfluenced at any duration of shallow-rearing. Although qualitative differences existed in the behaviors of those shallow- and deep-reared chicks which crossed the cliff, the loss of depth avoidance by the latter group appeared to be specific to the rearing and testing apparatus.

Animals↗
PubMed1976

Periodicity of death feigning by domestic fowl in response to simulated predation.

The presence and extent of periodicity in the manifestation of death feigning duration was assessed in 137 week-old White Leghorn chicks. Chicks were reared on an LD 12:12 regimen with light onset at 0800 hr. Each was tested only once at one of 13 clock hours spanning a 24 hr period. Death feigning duration varied significantly with clock hour of induction, being longest from 1300-1400 hr and briefest from 0600-1100 hr. Variability was also cyclic but was distributed bimodally, being greatest in the latter half of each L and D phase. There was no significant influence of management hour on death feigning duration. The adaptive significance of the periodicity for predator-prey interactions was discussed, as were methodological implications.

Animals↗
PubMedDate not supplied

Diisopropyl phosphorofluoridate (DFP) disrupts circadian activity patterns.

A single dose (1.75 mg/kg SC) of diisopropyl phosphorofluoridate (DFP) was given to rats living continuously in modified activity cages in which wheel running, lever pressing and feeding were monitored twenty four hours per day. The first twenty four hours following DFP injection was characterized by a marked reduction in all monitored activities. Within a few days, food intake and lever pressing had recovered to pre-injection levels, but running remained suppressed throughout the remainder of the experiment. A comparison of the circadian distribution of activities for individual subjects showed phase shifts and a reduction in amplitude of all three monitored activities, persisting well beyond the initial reductions in the daily totals.

Animals↗