Partial reinforcement and autoshaping of the pigeon's key-peck behavior

Pigeons were exposed to continuous and partial reinforcement (25%) schedules in an autoshaping procedure. The number of trials and/or pairings per session were equated across two factorial group sets and all groups were trained for a fixed total number of acquisition trials (192). When acquisition was analyzed as a function of reinforcements delivered, the groups receiving fewer number of trials per session acquired the response faster, independently of the percentage of reinforced trials. Moreover, the number of reinforcements to satisfy an acquisition criterion was a monotonic function of the number of trials per session but not of the schedule. The results are discussed in relation to the neocontinuity and the scalar expectancy theories.     

Toward a Better Understanding of Psychological Well‐Being in Dementia Caregivers: The Link Between Marital Communication and Depression

To read this article's abstract in both Spanish and Mandarin Chinese, please visit the article's full‐text page on Wiley InterScience ( http://interscience.wiley.com/journal/famp ). Dementia research has frequently documented high rates of caregiver depression and distress in spouses providing care for a partner suffering from dementia. However, the role of marital communication in understanding caregiver distress has not been examined sufficiently. Studies with healthy couples demonstrated an association between marital communication and the partners' psychological well‐being, depressiveness, respectively (e.g., Heene, Buysee, & Van Oost, 2005 ). The current study investigates the relationship between caregiver depression and communication in 37 couples in which the wives care for their partners with dementia. Nonsequential and sequential analyses revealed significant correlations between caregiver depression and marital communication quality. Caregivers whose husbands used more positive communication reported less depression and distress. Additionally, caregiver depression was negatively correlated with rates of positive reciprocal communication indicating dependence between the couples' interaction patterns. This study is one of the first to illustrate the relevance of spousal communication in understanding caregiver distress and depression.     

Can contextual cues control consummatory successive negative contrast?

Rats exposed to incentive downshift show behavioral deterioration. This phenomenon, called successive negative contrast (SNC), occurs in instrumental and consummatory responses (iSNC, cSNC). Whereas iSNC is related to the violation of reward expectancies retrieved in anticipation of the goal (cued-recall), cSNC involves reward rejection and may require only recognition memory retrieved at consumption. The three within-subject experiments reported here suggest that cued-recall memory can also operate in cSNC under some conditions. A small but significant cSNC effect was obtained when animals were exposed to the conditioning context during an average 90-s interval before the introduction of the incentive (either 16% or 2% sucrose solutions), rather than being given immediate access to the sucrose upon entry into the context (Experiment 1). Neither simultaneous contrast (Experiment 2) nor simple sequential effects (Experiment 3) contribute to this within-subject version of cSNC. These results suggest that cSNC can be shifted to a cued-recall mode with appropriate training parameters.     

Reexamining the frustration effect in rats: Aftereffects of surprising reinforcement and nonreinforcement

The reinforcement-omission effect (ROE; also called frustration effect), or greater response strength immediately after nonreinforcement (N) than reinforcement (R), has been traditionally interpreted in terms of one of two factors: transient facilitation after N induced by primary frustration or transient suppression after R induced by postconsummatory processes. Three instrumental lever-pressing experiments with rats demonstrated that the ROE can be caused by either factor in isolation, or by both acting simultaneously. The distribution of trials and the interval between N or R and the target response determine which factor would cause the ROE. Both aftereffects decay in time, but the after-N process decays at a slower rate than the after-R factor.     

Scaling relative incentive value in consummatory behavior

Surprising downshifts from more preferred (training incentive) to less preferred incentives (test incentive) are usually accompanied by emotional activation and suppression of conditioned behavior in rats. Two experiments were designed to determine whether consummatory behavior is similarly affected by downshifts of equal proportions. Within limits, the degree of consummatory responding during incentive downshift was similar with equal ratios of test concentration to training concentration. Thus, 32–4% and 16–2% downshifts (1:8 test/training ratios) caused similar levels of consummatory behavior, despite differences in the absolute concentrations of the solutions involved in the downshift. An interpretation based on sensory contrast was discarded because of the long intervals between training and test solutions (40 min and 24 h in Experiments 1 and 2, respectively). It is suggested that Weber’s law regulates behavioral suppression after reward downshifts. A theoretical framework for the interpretation of these data is presented.     

Between-subject PREE and within-subject reversed PREE in spaced-trial extinction with pigeons

Three experiments explored the partial reinforcement extinction effect (PREE; greater resistance to extinction after partial, rather than continuous, reinforcement training), in a spaced-trial situation with pigeons. Experiments 1 and 2 report conventional PREEs with 24-h intertrial intervals and between-subject designs. The corresponding outcome (food reinforcement or nonreinforcement) was delivered after satisfaction of a fixed-ratio 10 (Experiment 1) or a fixed-ratio 1 (Experiment 2). Experiment 3 reports a reversed PREE in a within-subject design with a fixed-ratio 10 requirement. Extinction occurred faster for the response paired with 50% partial reinforcement than for the response paired with continuous reinforcement. A third response paired with a small reinforcer (1 pellet/trial) in 100% of the trials extinguished faster than a response paired with a large reinforcer (15 pellets/trial). These results are discussed in the context of spaced-trial instrumental performance (key pecking and running), in pigeons.     

Apparent Incentive Contrast Effects in Autoshaping with Rats

The effects of shifts in reward quality and quantity on Pavlovian acquisition were studied in rats. In Experiment 1, animals preexposed to unsignaled food pellets, 10% sucrose solution, or home cage controls subsequently received autoshaping training (response-independent lever-pellet or lever-solution pairings, in three groups each). Unsignaled preexposure to sucrose solution facilitated autoshaping for pellets (relative to unshifted controls), whereas unsignaled preexposure to pellets retarded autoshaping for sucrose solution. In Experiment 2, unsignaled preexposure to 30% sucrose solution impaired acquisition reinforced by food pellets, relative to 2% solution. Using a choice procedure, Experiment 3 demonstrated that rats prefer pellets to either 2 or 10% sucrose solutions, but they prefer the 30% solution to the pellets. Experiment 4 demonstrated the facilitatory effect after an upward shift in reward magnitude rather than quality (from 1 to 12 pellets), but provided weaker evidence for retardation following a downward magnitude shift. Experiment 5 was similar to Experiment 4, except that animals received autoshaping training from the outset. No evidence of successive positive contrast was obtained, but there was a significant successive negative contrast effect. Moreover, extinction was faster after acquisition with 12 pellets rather than 1. These results suggest the presence of incentive contrast effects under Pavlovian training conditions.     

Psychodynamic treatment of failure in homeostatic organization in infancy

Failure in homeostatic organization in the early years of life is purported to indicate an early disorder in relationships. We report a method of psychodynamic psychotherapy with parents and child that addresses these problems with an emphasis on enhancing the maternal function. The nodal point of treatment consists of the “negotiation” between the needs of the child and the adaptive capacity of the environment, and includes both aspects of the primary adaptive modes: that of the child's ability to organize increasingly complex modes of adaptation and that of the organizing quality of the maternal function. One case is reported in depth to illustrate the problem and our psychotherapeutic approach.     

Duration of extinction trials as a determinant of instrumental extinction in terrestrial toads (<Emphasis Type="Italic">Rhinella arenarum</Emphasis>)

Instrumental learning guides behavior toward resources. When such resources are no longer available, approach to previously reinforced locations is reduced, a process called extinction. The present experiments are concerned with factors affecting the extinction of acquired behaviors in toads. In previous experiments, total reward magnitude in acquisition and duration of extinction trials were confounded. The present experiments were designed to test the effects of these factors in factorial designs. Experiment 1 varied reward magnitude (900, 300, or 100 s of water access per trial) and amount of acquisition training (5 or 15 daily trials). With total amount of water access equated in acquisition, extinction with large rewards was faster (longer latencies in 900/5 than 300/15), but with total amount of training equated, extinction with small rewards was faster (longer latencies in 100/15 than 300/15). Experiment 2 varied reward magnitude (1200 or 120 s of water access per trial) while holding constant the number of acquisition trials (5 daily trials) and the duration of extinction trials (300 s). Extinction performance was lower with small, rather than large reward magnitude (longer latencies in 120/300 than in 1200/300). Thus, instrumental extinction depends upon the amount of time toads are exposed to the empty goal compartment during extinction trials.     

Effect of schedule and magnitude of reinforcement on instrumental learning in the toad, Bufo arenarum

Extinction after training with continuous (CR) or 50% partial (PR) reinforcement, and with different magnitudes of reward, was studied in the amphibian Bufo arenarum, in a runway situation. In Experiment 1, a group of toads received massed-trial, CR training with access to water as the reward. Performance improved during acquisition, including an improvement on the first trial of each session. Extinction was rapid and there was evidence for spontaneous recovery of the running response. In Experiment 2, groups of toads received PR or CR training at a rate of one trial per day. PR impaired acquisition and resulted in poor responding during extinction, compared to CR. Experiment 3 factorially studied the effects of schedule (PR vs CR) and distribution of practice (15 s vs 300 s intertrial interval). Acquisition was impaired by PR training but had little effect on extinction performance. Different magnitudes of water reinforcement were used in Experiment 4 in a one-trial-per-day situation. Terminal acquisition performance was a monotonic function of reward magnitude, but there were no differences in extinction performance across groups. The results are discussed in relation to comparative and developmental data on the paradoxical effects of reward.