Septal lesions and incentive expectancies in rats.

Tested male albino Wistar rats with bilateral septal lesions on a multiple DRL schedule with large and small rewards. The lesion produced less efficient DRL performance under both conditions. Small rewards produced more efficient DRL responding in controls and brain-damaged Ss. A 2nd study investigated runway conditioning under immediate, delayed, and no reward. Septal lesions increased running speeds with immediate reward, maintained faster speeds during the early delayed-reward trials, but produced no differences during extinction. A 3rd experiment investigated the effects of immediate and delayed rewards on auditory discrimination learning in septal and control Ss. Brain-damaged Ss showed inferior discrimination performance with delayed rewards but not with immediate rewards. Data suggest that septal lesions alter cognitive strategies (i.e., expectancies) based on incentive characteristics. (French abstract) (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spaced-trials reward magnitude effects in the rat: Single versus multiple food pellets.

Trained 56 male Charles River hooded rats in a runway with either small- or large-reward magnitude. Both small and large rewards were presented in single- or multiple-pellet form. 1 training trial was given each day for 120 days. Early in training, the large-reward Ss ran faster than those receiving small reward, and the effect was more pronounced in the multiple-pellet condition. Later in training, the small-reward Ss equaled the performance of Ss receiving large reward and even ran somewhat faster in the run section of the alley. The typical extinction effect of greater persistence for small-reward Ss was observed, but only in the goal section. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partial delay extinction effects within-subjects based on sequential manipulations.

Describes an experiment with 4 groups of 10 male albino Sprague-Dawley rats. 3 groups received partial delay of reward in 1 runway and immediate reward in a discriminably different runway followed by extinction to both runways. Group 1, which received transitions from delay to immediate reward in the partial-delay alley, showed greater resistance to extinction in the partial-delay alley than in the immediate alley. Groups that received transitions from delay to immediate reward in the immediate alley (Group 2) and in both partial-delay and immediate alleys (Group 3) showed no differential within-S extinction performance. A between-group, partial-delay extinction effect was found; all Ss experiencing delay showed greater resistance to extinction than Group 4 (controls) that received only immediate reward. Data are interpreted within the framework of E. J. Capaldi's sequential theory. However, an extension of sequential theory was needed to account for the nondifferential extinction performance of Group 2. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced frustrative nonreward effect following 6-hydroxydopamine lesions of the lateral septum in the rat.

Tested the effect of local injections of 6-hydroxydopamine (6-OHDA [3 μg/1 μl]) into the lateral septum in a paradigm that leads to an energizing behavior, through a possible frustrative effect, induced by partial or total omission of reward in hungry adult male Sprague-Dawley rats. Biochemical assays in the septum showed that 6-OHDA reduced endogenous dopamine and, to a lesser extent, noradrenaline concentrations and left intact noncatecholaminergic neurons such as serotoninergic terminals. In a double straight alley, Ss were exposed to an acquisition phase, a partially reinforced phase, and an extinction phase. Ss with lesions ran faster for food than controls in the partial reinforcement or extinction situation. The 2 groups also behaved similarly after the 1st 6 trials of the extinction phase. When Ss were tested in a leverpress conditioning task, lesioned and control Ss learned this task equally well, both with respect to the number of leverpresses and the time to obtain a fixed number of food pellets. In the 1st 5 min following the omission of reward, the number of leverpresses increased more for the lesioned Ss than for controls, a difference that disappeared in the later stages of the test. Results indicate that the loss of septal dopaminergic innervation produces behavioral effects similar to those obtained after total destruction of the same areas by electrocoagulation. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of type of deprivation and sucrose concentration on the acquisition and extinction performance in the rat.

In a discrete-operant barpress situation with 128 female albino Sprague-Dawley rats, 4 types of deprivation (food, water, water plus food, and no deprivation) were combined factorially with 4 levels of reward (0, 4, 16, and 64% sucrose concentration). In acquisition, water (0% sucrose) served as an effective reinforcer only when Ss were deprived of water alone. Higher sucrose concentrations tended to produce correspondingly higher levels of performance when food, water plus food, and no deprivation were used. No such differences were obtained with water deprivation. Resistance to extinction was an increasing function of sucrose concentration when Ss were deprived of food and water plus food. No differences were observed under the other 2 deprivation conditions. (French summary) (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine seeking by rats is a goal-directed action.

In 2 experiments rats were trained to self-administer intravenous cocaine on chained schedules using different responses in the initial (drug-seeking) and terminal (drug-taking) links. In both between- (Exp 1) and within-subject designs (Exp 2), the drug-taking response was then either extinguished or reinforced in the absence of the opportunity to perform the seeking response. In a subsequent extinction test with the seeking manipulanda alone, the rate of drug seeking was reduced after the prior extinction of the associated taking response. An additional group trained with a sucrose reinforcer showed a comparable devaluation effect. These findings demonstrate that seeking responses for cocaine and food rewards are mediated by a representation of the contingency between seeking response and the opportunity to take the reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Runway alternation and discrimination of mice with limbic lesions.

Trained 7 normal male HS mice (Norm), and 18 mice with septal (Sept) and cingulate-anterior limbic cortex lesions (Cing) in a straight-alley single-alternation task. Sept Ss performed significantly better than Norms, running faster on reinforced trials and slower on nonreinforced trials. Cing Ss performed as well as Norms. In a 2nd experiment with 64 Ss, Norm and Sept Ss learned a discrimination task using a food pellet or sound of a buzzer as a cue for either reinforced or nonreinforced trials. Sept Ss learned the food-cued task faster than Norms when nonreinforced trials were cued; Norms performed better when reinforced trials were cued with the buzzer. Results suggest that septal lesions enhance the cue value of food, and contradict the hypothesis that the septum is involved in response inhibition. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adrenal responses to reinforcement and extinction: Role of expectancy versus instrumental responding.

Measured plasma corticosterone levels during operant conditioning to determine the effect of reinforced and nonreinforced responding (extinction) on adrenal activation; Ss were 44 male Long-Evans rats. The influence of instrumental responding was assessed by comparing trained Ss with yoked Ss that received a matched reward schedule in the absence of an operant task. Reinforcement sessions resulted in a significant decrease in adrenal secretion at 20 min but not at 5 min, whereas extinction caused a rapid increase in corticosterone levels at 5 min and an even greater elevation at 20 min. Comparison of the operant and yoked Ss showed that this effect of reinforcement and extinction was not dependent on instrumental responding, but rather on the receipt or withdrawal of the expected reward. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commitment to social deprivation and verbal conditioning.

Control Ss who experienced high prior deprivation of a reinforcing stimulus (approval) responded more with a reinforced response in a verbal conditioning situation than Ss less deprived. Other Ss committed themselves to undergoing postexperimental deprivation of social reinforcement after the same high prior social deprivation. A model suggested by dissonance theory predicted that such Ss who committed themselves for lower rewards would experience greater dissonance; the greater the dissonance, the more could Ss justify their decisions and reduce dissonance by reducing their motive for social reinforcement, consequently behaving in the conditioning situation as Ss who had low motivation for social reinforcement. As expected, experimental Ss in the High Dissonance condition who committed themselves for low reward ($1.00) responded less to social reinforcement, i.e., they showed a smaller increase in response strength of emission of verbal behavior than Control Ss or Low Dissonance Ss who committed themselves for high reward ($5.00). (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When rewards reflect competence: A qualification of the overjustification effect.

Suggests that it is not contingency per se, but whether the rewards provide information about the Ss' competence, that determines how Ss will react to rewards. Results from 118 female university students reveal that when rewards did not indicate level of ability, higher rewards led to less intrinsic motivation, regardless of whether these rewards were contingent. But when the level of reward reflected ability (higher rewards were supposedly given for greater skill), higher rewards led to greater intrinsic motivation. This latter result is similar to findings in the control condition in which Ss were not given any rewards but were given competency information. Results are discussed in terms of their application to educational and business settings where rewards are often based on ability. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for unpredictable food rewards occurs with high proportion of reinforced trials or alcohol if rewards are not delayed.

A recently developed mathematical model (DMOD) also predicts that Ss prefer the unpredictable reward situation under conditions that substantially decrease aversiveness of unpredictable nonreward (Daly & Daly, 1982). Because a high proportion of reinforced trials (lenient schedule) and alcohol decrease aversive conditioning, these variables were tested with rats in 5 E-maze experiments. A choice to 1 side of the maze resulted in a stimulus uncorrelated with reward outcome (unpredictable). A choice to the other side resulted in stimuli correlated with reward and nonreward (predictable). Stimuli were not visible until after the choice was made. A lenient reinforcement schedule resulted in preference for the unpredictable reward situation if rewards were not delayed. Alcohol resulted in preference for the unpredictable reward situation if a medium 5-pellet reward was given. A lenient reinforcement schedule combined with an alcohol injection resulted in faster acquisition of the preference for the unpredictable reward situation than did a lenient schedule combined with a saline control injection. These results pose a major challenge to most theories, yet were predicted by DMOD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irrelevant-incentive learning under hunger and thirst as assessed by discrimination transfer.

Two groups of 64 male albino rats received 2 food (F) and 2 water (W) rewarded trials daily in the alternating sequence FWFW. One group was hungry in Phase I and thirsty in Phase II (HA-TA) while the other was thirsty in Phase I and hungry in Phase II (TA-HA). As assessed by the rate of development of appropriate pattern running in Phase II, HA-TA demonstrated positive transfer and TA-HA negative transfer relative to controls. It is concluded that in addition to learning excitatory and inhibitory habits in Phase I, hungry Ss also learned expectancies regarding the ordering of specific rewards which facilitated the development of appropriate patterning in Phase II. Thirsty Ss either failed to learn specific reward expectancies in Phase I, or if formed, the facilitative effect of these expectancies on Phase II performance was masked by a strong inhibitory habit learned in Phase I. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of differences in suggestibility within self- and external-control conditions.

Studied possible effects of differences in waking suggestibility on performance within self- and external-control conditions. 10 high-suggestible and 10 low-suggestible undergraduate Ss, as measured by body sway, were assigned to each of 3 experimental conditions—self-control, external-control, and no reward. Response rates of self and external groups were higher than the no-reward group. However, response rates of high-suggestible Ss in the self-control condition were not significantly different than similar Ss in the no-reward groups. Moreover, performance of high- and low-suggestible Ss was not significantly different in the external-control condition, whereas response rates of high-suggestible Ss were significantly lower than low-suggestible Ss in the self-control condition. It is concluded that low-suggestible Ss respond equally well to either self- or external demands and rewards, whereas high-suggestible Ss are so dependent on external factors that their performance is minimal when self-determination of reward contingencies is required. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of conceptions of prosocial behavior: Information affecting rewards given for altruism and kindness.

82 graduate students, 33 1st graders, and 31 5th graders were presented with information about situations in which one child either helped someone (kindness) or gave something to someone (altruism), with Ss allocating rewards for different actors. Younger children used an additive principle by allocating greater rewards for behavior that led to positive consequences for the actor or avoided negative consequences. Older children and adults utilized a discounting principle by allocating greater rewards for behavior that initially led to no reward or occurred under the threat of harm. Younger and older children allocated greater rewards for altruistic behavior following a previous obligation (facilitory obligation) to the recipient of the act, whereas adults allocated greater rewards for behavior toward a recipient who previously denied a favor to the actor (inhibitory obligation). Ss at all ages allocated greater rewards for actors whose previous behavior was consistently kind or altruistic (high consistency) or who were kind or altruistic to persons other than the recipient described in the stories (low distinctiveness). Results are discussed in terms of causal schemes underlying preconventional and conventional moral judgments and the use of covariation principles in inferences of causality. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of intrahippocampal administration of colchicine on incentive contrast and on radial maze performance.

Examined the behavior of rats given intradentate injections of colchicine (COL). In Exp 1, COL-treated, artificial cerebrospinal fluid (CSF)-treated, and untreated Ss did not differ in the intake of 32% and 4% sucrose solutions, nor did they differ in degree of successive negative contrast when the 32% solution was changed to 4% sucrose. In Exp 2, the COL-treated and CSF-treated Ss did not differ in degree of suppression in the intake of a 0.15% saccharin solution when it preceded 32% sucrose in once-daily pairings (anticipatory contrast), nor did they differ in reversal performance when saccharin–sucrose and saccharin–saccharin pairings were reversed. In Exp 3, the COL-treated Ss were substantially impaired in radial-arm maze performance compared with CSF-treated controls. Results suggest that a completely functioning hippocampus is not necessary for the memory of reward quality, the comparison of rewards, the suppression of behavior when reward is decreased, the formation of associations between 2 levels of reward, and the reversal of this association, as long as these processes are reflected in consummatory behavior. Data are interpreted in terms of differences between instrumental behavior and sensory memory and/or consummatory behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rewarding pinball wizardry: Effects of evaluation and cue value on intrinsic interest.

Examined the effects of rewards for pinball competence on subsequent interest in the game in 3 studies with 219 Ss in which 3 components of performance-contingent reward structures—an evaluative contingency established before playing, performance feedback, and the receipt of a reward—were identified. The symbolic cue value of the reward may affect interest independently of evaluation and competence feedback. To isolate its effect, groups receiving a performance-contingent reward were compared with groups that experienced the same evaluative contingency and feedback and with feedback-only controls (Studies 1 and 3). Results show that evaluation reduced intrinsic motivation, compared with controls, whereas reward enhanced intrinsic motivation relative to evaluation. In Study 2, groups receiving rewards for attaining competence but differing in whether the evaluation was anticipated before playing were compared. Results indicate that unexpected performance-contingent rewards enhanced interest, compared with expected rewards. Findings suggest that the 3 reward properties have separate effects on intrinsic motivation. Anticipation of evaluation was responsible for negative reward effects, whereas competence feedback and due value had independent positive effects (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of reward contingency and performance feedback on intrinsic motivation.

93 high school students were offered performance or task-contingent rewards or no reward for doing hidden-figures puzzles. Ss offered performance-contingent rewards all received positive feedback concerning performance, and half the Ss in task-contingent and no-reward conditions received the same positive feedback. Performance-contingent rewards were found to undermine intrinsic motivation more than task-contingent ones, which produced decrements relative to control conditions of no reward, supporting E. Deci's (1972, 1975) control model. Positive feedback enhanced intrinsic motivation; this effect was independent of reward effects. A recall measure indicated that Ss receiving performance-contingent rewards remembered fewer performance-irrelevant details about the task, suggesting that rewards may affect the process of task involvement as well as its motivational outcomes. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overjustification and children's intrinsic motivation: Comparative effects of four rewards.

Studied the relative overjustifying effects of various types of rewards on 30 boys' and 30 girls' (mean ages 72.6 and 72.4 mo, respectively) intrinsic motivation. Four reward procedures were examined—tangible, verbal, symbolic, and self-administered symbolic (self) rewards. Ss attempted to solve mazes under 1 of 5 training conditions and were then given a free-play period in which to engage in further maze play or try other materials. Ss receiving tangible rewards and those who self-administered symbolic rewards (self-reward) showed less subsequent intrinsic motivation than Ss in the control, verbal reward, and symbolic reward conditions. Moreover, internal locus-of-control expectancies (Stanford Preschool Internal–External Scale) were inversely related to intrinsic motivation for Ss in the self-reward condition. Results are discussed from 2 perspectives—the intrinsic–extrinsic reward continuum and E. L. Deci's (1975) distinction between the controlling (detrimental) and informational (competence- and motivation-enhancing) aspects of rewards. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competition and summation between rewarding effects of sucrose and lateral hypothalamic stimulation in the rat.

Rats were offered a forced choice between a train of brain stimulation that varied in strength from trial to trial and a fixed standard reward. This standard reward consisted of an intraoral sucrose infusion presented either alone or paired with an equipreferred train of brain stimulation. Postingestional effects were minimized by opening a gastric cannula. The presence of a sucrose standard led the Ss to forgo trains of brain stimulation for which they had responded when the sucrose was absent. The strength of the brain stimulation required to balance the compound reward exceeded the stimulation strength required to balance a reward consisting of sucrose alone. These results imply that the rewarding effects of brain stimulation and intraoral sucrose can be evaluated in a common system of measurement and combined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Type of start box and goal box distinctiveness in self-punitive running of rats.

A total of 96 male Sprague-Dawley rats were first trained to escape shock in an alley by running to a safe goal box. In Exp I either a trapdoor-floored start box or a guillotine-door start box was used in different groups. In extinction, nonpunished and punished subgroups were tested in each of the start-box conditions. Punishment produced faster running speeds than nonpunishment (self-punitive effect) only with the trapdoor. The trapdoor start box was used in Exp II, and independent groups of Ss were trained to escape to a goal box that was either very dissimilar or similar to the shock area. Nonpunished and punished subgroups were extinguished in each goal box condition. Self-punitive running was more likely with the dissimilar goal box. (PsycINFO Database Record (c) 2010 APA, all rights reserved)