Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively.

For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward (from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction as a function of magnitude and percentage of food or sucrose reward.

64 male hooded rats in 8 groups were trained to run an alleyway and extinguished. For groups given food rewards, extinction performance was dependent on an interaction of the magnitude and percentage of reward in acquisition: in consistently reinforced Ss, large rewards led to slower running in extinction, but in partially reinforced Ss, large rewards led to faster running. With sucrose as the reward, however, large rewards (higher concentration) led to faster running in extinction irrespective of the schedule of reinforcement. These differences between food and sucrose are discussed in terms of frustration theory and sequential theory. The simplest interpretation, within the context of sequential theory, is to assume that different concentrations of sucrose, although differing in their reinforcing effects, do not produce discriminably different aftereffects. (French summary) (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Species generality of within-subjects reward magnitude effects.

12 female pigtail, stumptail, and squirrel monkeys and 4 female Holtzman albino rats were given acquisition, extinction, and reacquisition training in a discrete-trials 2-lever spatial discrimination situation. In acquisition the left and right levers were associated with 5- and 1-pellet rewards, respectively, and in reacquisition, response to either lever produced 5-pellet reward. The 4 species showed similar patterns of preference for the 5-pellet lever on 2-lever choice trials and differential responding on 1-lever forced trials in acquisition, and similar within-Ss extinction effects which were at variance with the typical crossover of large- and small-reward extinction curves in between-groups reward magnitude studies with rats. Species differences appeared in over-all relative rate of extinction, with the macaques showing the fastest extinction, and in the degree to which historical effects of acquisition conditions appeared and persisted in reacquisition. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth of brain stimulation reward as a function of duration and stimulation strength.

The strength of a train of rewarding brain stimulation required to support a criterion level of operant performance declines hyperbolically as the duration is increased. This finding has been attributed to a process of leaky integration. However, the rate at which integration approaches asymptote has been shown to depend on stimulation strength, a finding that differs from the behavior of a simple leaky integrator. The authors replicate both findings and show that they are both well described by a new model that incorporates a hyperbolic strength-duration function, a logistic function mapping stimulation frequency onto reward intensity, and another logistic function mapping reward intensity onto performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for alcohol consumption as a function of amount and delay of alternative reward.

Sixty male normal drinkers were placed in a choice situation with two behavioral alternatives; one produced access to alcohol consumption, and one produced access to opportunities to win money on a probabilistic dice throw task. Any alcohol chosen was available during the session, and constraints on access to it were held constant. Two independent variables involving constraints on access to money were manipulated in a 2?×?3 factorial design: (a) amount of money available, which was determined by the probability of a "win" on the dice throw task (either .17 or .83), and (b) delay in receipt of any money won (either no delay, a 2-week delay, or an 8-week delay). The main dependent measures were the proportion of responses allocated to gain access to alcohol, response-outcome expectancies, and mood state. Subjects' preferences for alcohol varied positively with delay but were not significantly influenced by the money-amount manipulation. Subjects' choice behavior was not related to mood states or expectations. The results partially replicate those of an earlier experiment and lend credence to a formulation of the determinants of drinking behavior based on behavioral theories of choice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of relative magnitude of reward and type of need on satisfaction.

Tested the hypothesis of an interaction between type of need and magnitude of relative reward in their effect on level of satisfaction. It was predicted that there would be gradually increasing differences between satisfaction scores of large vs small magnitude of relative reward as the need was located in a higher position on A. Maslow's (1954) need hierarchy (excluding the self-actualization need). The analysis of the reactions of 40 female married 18-40 yr old undergraduates to a questionnaire designed for this purpose confirmed the hypothesis. Findings are discussed in terms of the social comparison and Maslow's hierarchy theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative steepness of approach and avoidance gradients as a function of magnitude and valence of incentive.

20 undergraduates tapped rapidly to either win (approach) or avoid losing (avoidance) sums of money. The experimental design permitted height and steepness of arousal gradients to be examined as a function (a) of magnitude of incentive, with valence and quality of incentive held constant; and (b) of valence of incentive, with magnitude and quality of incentive held constant. An increase in incentive increased both the slope and height of approach and avoidance arousal gradients. Results support the conceptualization of motive strength as a multiplicative function of drive-related cues and an internal state rather than as an additive function, as proposed by N. E. Miller (1944, 1959). Avoidance gradients were significantly steeper than approach gradients, but the effect was not very robust and was far from uniform across Ss, some of whom produced much steeper approach than avoidance gradients. It is concluded that although there may be an intrinsic tendency for avoidance gradients to be steeper than approach gradients, this tendency is not strong and is easily reversed, giving rise to "avoidance–approach" conflict. Such conflict has interesting theoretical and practical implications that have not been recognized because of uncritical acceptance of the assumption that avoidance gradients are invariably steeper than approach gradients. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effectiveness of learned reinforcement as a function of primary reward percentage and number of primary pairings.

136 male albino rats were trained while water-deprived to lever-press for water reinforcement. Then, with the lever retracted and while food-deprived, different groups were administered either 40, 80, 160, or 320 pairings of a neutral stimulus (sN)compound, light and feeder "click," with primary reinforcement (sR). The 45-mg reward was presented on either a 25, 50, or 100% schedule. The design was thus a 3 * 4 factorial. Control groups which received no pairings (N = 10) or 80 nonreinforced presentations of the sN (N = 6) were included. During testing, with the lever inserted, the light and "click" compound followed each lever-pressing response. Results indicate that effectiveness of secondary reinforcement was an inverted U shaped function of percentage of sR, and an over-all increasing linear function of number of sN sR pairings. (French summary) (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arousal of frustration following gradual reductions in reward magnitude in rats.

16 male Holtzman rats were assigned to each of 4 groups; Ss were given a 14-pellet reward for 60 runway acquisition trials. During a subsequent 18-trial shift phase, one group was shifted to a 1-pellet reward on Trial 1, a 2nd was shifted on Trial 13, and a 3rd was given 1 less pellet each trial and then 1 pellet for the last 6 trials. The speeds of all 3 groups decreased to a level below that of a control group given a 1-pellet reward throughout training. All Ss were then given hurdle-jump training to escape from the 1-pellet reward to a neutral box. All 3 shifted groups showed acquisition of the response, whereas the control group did not. Results indicate that both gradual and abrupt reward reductions arouse frustration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The frequency of self-reference statements as a function of generalized reinforcement.

Skinnerian-oriented research has demonstrated that interpersonal verbal behavior may be influenced by conditions of operant conditioning. Within this framework, the present research tests the effect of an interviewer's attention and assent on the frequency of self-reference statements made by an interviewee. These interviewer variables were observed to function as a reinforcing state of affairs without the interviewee being aware of the conditions of the experiment. Several explanations are offered for the results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resistance to extinction in rats as a function of deprivation level and schedule of reward in acquisition.

Conducted 3 straight-alley investigations with 84 male and 44 female Holtzman albino rats. 2 levels of deprivation were combined factorially with 2 schedules of reward (50 or 100%) in acquisition. Deprivation level in extinction was equated. When extinction deprivation level was low either there was no difference in extinction due to acquisition deprivation level or groups trained under high deprivation were more resistant to extinction than groups trained under low deprivation, as they were when deprivation level was high in extinction. It is suggested that at least 2 factors influence resistance to extinction as a function of acquisition deprivation level deprivation-related stimuli and some factor which produces greater resistance to extinction following high deprivation in acquisition. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for delayed reward as a function of age, intelligence, and length of delay interval.

"Using a simple choice measure of preference for delayed reward on elementary school children… ranging in age from 5 to 12, and under five different lengths of delay interval, the following hypotheses were tested and confirmed: (a) preference for delayed reward is positively related to age; (b) positively to intelligence; (c) and negatively to length of the delay interval… . An additional finding was that subjects preferring the immediate reward tend to have more variable future time perspectives and that length of time perspective is slightly related to IQ, but not to age." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-unrelated thought frequency as a function of age: A laboratory study.

Using retrospective reports, Giambra (1977–1978, 1979–1980) found an inverse relation between age and daydreaming/mind wandering. To deal with an alternate explanation of these results based on age-dependent memorial deficiencies and attitudes toward daydreaming/mind wandering and to provide independent convergent validity, five experiments were carried out. Task-unrelated thoughts (TUTs) were taken as the operational definition of daydreams/mind wanderings and their frequency recorded in vigilance tasks. All five experiments found an inverse relation between age (17–92 years, N?=?471) and TUTs, confirming the reliability and validity of the earlier studies. The age-dependent reduction in TUTs was considered as evidence of reduced nonconscious information processing with increased age. The results of this study were incompatible with a recent theory that predicts for older individuals an increased input of irrelevant thoughts into working memory due to the older individual's reduced inhibitory control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Midazolam administered to rats induces anterograde amnesia for changes in reward magnitude.

L. P. Crespi (1942) showed that rats trained to run an alley for a large food reward slowed down when shifted to a small reward. This effect is usually interpreted as an aversive emotional response to reward reduction (A. Amsel, 1958). Benzodiazepines attenuate the behavioral effects of reward reduction (C. F. Flaherty, 1990), but the emphasis has been on their anxiolytic, not memory-impairing, effects. Researchers trained rats (175–200 g) to run an alley for food until asymptote was reached. Reward magnitude was then either decreased (Experiment 1) or increased (Experiment 2). The benzodiazepine midazolam (1 mg/kg ip), injected immediately prior to a decrease or increase in reward magnitude, impaired the later retention of both changes in a manner consistent with anterograde amnesia. The findings suggest that the memory-impairing effects of benzodiazepines may, at least in part, influence the response to reward reduction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solving anagrams as a function of word frequency, imagery and distribution of practice.

While previous research has consistently demonstrated that anagrams with solution-words of high frequency are easier to solve than anagrams with solution-words of low frequency, the results for solution-word imagery have been contradictory. Experiment I involved the use of four six-item lists which varied factorially on imagery and frequency and were equated for meaningfulness and total bigram-position frequency. Eighteen Ss attempted to solve these anagrams under conditions of distributed practice and 18 Ss under massed practice. Data for solution latency and number of solutions revealed that anagrams were easier to solve if the solution-words were of high imagery or high frequency (ps ps     

Responsiveness to conservation training as a function of induced subjective uncertainty, M-space, and cognitive style.

According to M. Lefebvre and A. Pinard (1972), conflict training can be successful in inducing conservation, but only if children's habitual subjective certainty is disturbed first. To test this notion, 54 low-socioeconomic-status nonconservers, aged 5-8 yrs, were trained with Lefebvre and Pinard's conflict procedure, preceded by activities which induced either high, neutral, or low subjective uncertainty. A comparable group of 9 Ss served as controls. Tests of M-space, field dependence, and impulsivity (backward digit span, portable rod-and-frame test, and Matching Familiar Figures Test, respectively) were administered as covariates. None of the control Ss showed any improvement from pretest to posttest, whereas 50% of the treatment Ss did. However, while improvement was strongly related to M-space ( r = .52), there was no effect due to the preliminary activities or to cognitive style. Results suggest that sensitivity to conflict is not a function of the S's initial degree of subjective uncertainty, but rather of his capacity to coordinate cues and to perceive conflict. To account for the relationship between conflict and M-space, the neo-Piagetian model of conservation proposed by J. Pascual-Leone (1970) is presented and expanded to include a preliminary stage where the resolution of cue conflict in quantification tasks leads to the creation of an executive scheme appropriate for solving the conservation problem. (French summary) (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of varied preshift reward magnitude on successive negative contrast effects in rats.

A total of 110 male Sprague-Dawley albino rats, distributed across 3 experiments, received simple instrumental conditioning trials in a straight runway. In each experiment the conditions of reward prior to a shift to small reward were varied between groups. Collectively, results indicate that the extent of the negative contrast effect depends upon the difference between pre- and postshift incentive levels and that Ss exposed to varied reward magnitude training average the incentive values of these rewards. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralization of high frequency, amplitude modulated sounds as a function of carrier frequency

Twenty subjects made graphic ratings of the perceived laterality of amplitude modulated sounds that were presented through earphones. A 200 Hz modulation frequency was combined with carrier frequencies of 2200 Hz, 3200 Hz, 4200 Hz, and 5200 Hz. The modulator sinusoid was delayed to either ear by temporal intervals ranging from zero to 0.6 ms. A significant interaction of carrier frequency with the linear trend for interaural temporal disparity indicated that the slopes of laterality ratings on temporal disparity decreased with carrier frequency. A significant interaction of carrier frequency with the difference in ratings for the 0.6 ms delays to the two ears indicated that the range in laterality ratings decreased with carrier frequency. The results indicate that the amount of laterality is a decreasing function of carrier frequency for high frequency sounds, which may be a consequence of greater weight being given to zero intensity difference as frequency increases.