Immediate and delayed reinforcers for flavor preferences in rats

When rats received, on alternate days, one flavored saccharin solution for 5 min and a differently-flavored saccharin solution for 60 min, they showed no consistent preference between the flavors. On the other hand, when they received one flavor in a concentrated saccharin solution and a different flavor in a dilute one, they preferred the first flavor in tests with saccharin concentration held constant; also, rats learned to prefer a flavor immediately followed by a concentrated saccharin solution to one followed by nothing. They showed no consistent preference, however, between a flavor followed 30 min later by a concentrated saccharin solution and one followed by nothing; but they learned to prefer a flavor followed 30 min later by a dextrose solution to one followed by nothing. In other words, consummatory responding did not reinforce flavor preference, sweet taste did so with immediate but not delayed reinforcement, and nutrition did so even with delayed reinforcement.     

Compounds of conditioned fear stimuli

A differential conditioning procedure was used with rats to establish different levels of suppression to two different stimuli. One stimulus was paired with shock every time it was presented, while the other stimulus cued shock on only 25% of its presentations. When these two component stimuli were subsequently tested as a simultaneous compound, two different types of component-compound relationships were observed. Some subjects showed greater suppression to the compound than they did to either component stimulus, while other subjects showed an intermediate level of suppression to the compound. The difference in type of component-compound relationship appeared to be related to the degree of stability (over trials) of each subject's reaction to the probabilistic (25%) cue.When a similar discrimination was established based on the intensity of the shock, rather than its probability of occurrence, all subjects showed more suppression to the compound than to its individual component stimuli. These results are discussed in terms of their implications for choice of model for characterizing the interaction of conditioned states.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

Involvement and response language effects in attitude scaling

An analytic procedure was developed for separating the effects of involvement from the number of response language categories the subject employs in judging a set of sentence stimuli. The procedure treats category usage as an independent variable and an aspect of the subject's response language. Category usage was shown to have significant influence on several attitudinal judgment processes: Informational complexity, mean judgment functions, and a successive intervals analysis testing Thurstone's assumption of the effect of involvement on equal category spacing. The decrement in scale responding typically associated with involvement is shown to depend on category usage operating either singly or in interaction with involvement. Some tentative conclusions about category usage as a response language variable are discussed.     

Expectation theories of decision making for duplex gambles

Complete tests of subjectively expected utility (SEU), subjectively expected value (SEV), expected utility (EU) and expected value (EV) theories were made for duplex gambles without measuring subjective probability or subjective utility. All gambles were hypothetical and offered on booklets. The duplex gambles consisted of winning gambles, which offered a chance to win a certain amount of money or to break even; and losing gambles, which offered a chance to lose a certain amount of money or break even.The results indicated that SEU, SEV and EU theories could not account for the strategies of 33%, 53% and 86% of the Ss respectively in the losing form of gambles, while EV theory accounted for 78% of the behavior of Ss.In the winning form of gambles, SEU, SEV and EU theory held for 77%, 65%, and 54% of the Ss respectively, while EV theory held for only 40% of the Ss. Suggestions for further research were made.     

Interactive effects of deprivation in the albino rat

The interactive effects of feeding and drinking schedules were investigated in three experiments. Twenty-four hour water-deprived rats consumed their entire obligatory water intake prior to feeding, whereas 24-hr food-deprived rats consumed only small quantities of food prior to drinking. This drinking was apparently due to a shift of water stores rather than an actual negative water balance. Experiment 3 investigated the effects of 24, 48, or 72 hr of water, food, or total deprivation. Water-deprived rats did not adequately suppress food intake and became thirstier than totally deprived rats. The effects of total deprivation were essentially identical to those of food deprivation. These experiments indicate the degree to which deprivation schedules impose restrictions on the reinforcement parameters of behavioral experiments.     

Bilateral tachistoscopic word perception of stutterers and normal subjects

Bilateral tachistoscopic procedures were utilized to investigate the visual half-field preferences of 15 stutterers and a group of 15 normal controls. Statistical analyses indicated a right visual half-field preference for the control group. In contrast, a significant visual half-field preference was not revealed for the stuttering group. However, further analysis revealed that a significantly larger proportion of stutterers, compared to controls, demonstrated a left visual half-field preference. Results indicated reversed cerebral processing for the stuttering group as compared with the control group.