Comparisons of stimulus learning and response learning in a punishment situation

These experiments use a procedure in which a rat is trained to make two topographically distinct responses on a single manipulandum, and then one of the responses is punished. Differential suppression of the punished response is taken as evidence of response learning, whereas the common suppression of both responses is attributed to stimulus learning or to general and nonassociative factors. Thus, this procedure begins the experimental separation of animals learning about the consequences of their behavior and animals learning what happens in a particular environment. A further separation is effected by using two such manipulanda; this procedure begins to distinguish between stimulus learning about the manipulandum and the more gereral factors that cause suppression. Some parameters affecting the relative importance of stimulus learning and response learning are examined.     

Reaction to punishment, reflectivity, and passive avoidance learning in extraverts

Passive avoidance learning occupies a central role in accounts of disinhibited behavior, ranging from psychopaths' persistent criminality (Hare 1970) to extraverts' gregariousness (Gray, 1972). To explore the mechanism underlying passive avoidance deficits, we assessed the relation of extraversion, neuroticism, and response latency after punishment to passive avoidance learning by using two successive go/no go discrimination tasks. The tasks were designed to examine two aspects of subjects' reactions to punishment: response speed on trials immediately following punishment (Experiment 1) and time to terminate punishment feedback between successive trials (i.e., reflectivity; Experiment 2). Consistent with previous findings, the results of Experiment 1 showed that extraverts commit more passive avoidance errors than introverts do (Newman, Widom, & Nathan, 1985) and fail to pause following punished errors (Nichols & Newman, 1986). In Experiment 2, only neurotic extraverts displayed this pattern of performance differences. In both experiments, longer pausing following punishment predicted better learning from punishment for both introverts and extraverts. These results suggest that, in the presence of salient cues for reward, extraverts' characteristic reaction to punishment interferes with processing punished errors and may contribute to their more general propensity for impulsive, nonreflective action.     

Stimulus specificity in avoidance learning

The present experiments address the issue of stimulus specificity in fear and avoidance learning. First, it was established that light stimuli are effective warning signals (WS) in shuttle avoidance. Then light stimuli were shown to produce conditioned suppression in the conditioned emotional response situation comparable to that produced by noise conditioned stimuli. Finally, the effectiveness of noise onset and noise offset as feedback signals was tested. This was assessed under conditions of immediate and delayed termination of a light WS. Delayed termination of a light WS interfered with avoidance learning and the introduction of noise offset as a feedback signal enhanced it. The only demonstration of stimulus specificity was the failure of noise onset to function as a feedback signal.     

The learning of goal-directed locomotion: A perception-action perspective

This study was designed to better understand the process underlying the learning of goal-directed locomotion. Subjects walked on a treadmill in a virtual reality setting and were asked to cross pairs of oscillating doors. The subjects' behaviour was examined at the beginning of the learning process (pretest), after 350 trials (intermediate test), and after 700 trials (posttest). The data were analysed at three different levels, each representing a specific aspect of the global response: performance outcome, displacement kinematics, and current arrival condition. While some aspects of performance outcome suggested the presence of a ceiling effect in the intermediate test, both displacement kinematics and current arrival condition clearly highlighted continuous transformations of the control mechanism involved. The learning process is best described as (1) the establishing of a relationship between specific information and a movement parameter and (2) the optimization of this relationship. The optimization process is characterized by the further exploration of the available behavioural repertoire and by the refinement of the dialogue between information and movement.     

Aversive learning overcomes appetitive innate responding in honeybees

Despite their miniature brain, honeybees have emerged as a powerful model for the study of learning and memory. Yet, they also exhibit innate responses to biologically relevant social signals such as pheromones. Here, we asked whether the bees’ developed learning capabilities allow them to overcome hardwired appetitive responses. Can they learn that attractant pheromones, that are not normally associated with a noxious stimulation in nature, predict the punishment of an electric shock? Immobilized honeybees were trained to discriminate two odorants, one that was paired with a shock and another that had no consequences. We measured whether they learned to produce aversive sting extension responses to the punished but not the non-punished odorant. One odorant was a neutral odor without innate value while the other was either an attractive pheromone (geraniol or citral) or an attractive floral odorant (phenylacetaldehyde). In all cases, bees developed a conditioned aversive response to the punished odorant, be it pheromone or not, and efficiently retrieved this information 1 h later. No learning asymmetries between odors were found. Thus, associative aversive learning in bees is strong enough to override preprogrammed responding, thus reflecting an impressive behavioral flexibility.     

Working memory load in the initial learning phase facilitates relearning: a study of vocabulary learning

In this study, the effect of working memory load in the initial learning phase on the relearning phase was examined. Exp. 1 examined the effect of articulatory suppression in paired associative learning with a relearning method. In the learning phase, 28 participants (M age=21.8 yr., SD=2.1) learned all word-nonword associations under conditions of articulatory suppression or simple tapping. After a delay, they answered a cued recall task in a nonsuppressed condition and a relearning task in a simple tapping condition. The subjects who learned under the simple tapping condition in the learning phase required significantly more trials in the relearning phase. In Exp. 2, 28 participants (M age=20.8 yr., SD=1.5) participated, and the result was replicated. These results suggested that working memory load facilitates relearning. Results are best explained by contextual interference (Battig) rather than by the less-is-more hypothesis of Newport.     

Drug-behavior interaction history: modification of the effects of morphine on punished behavior.

Squirrel monkeys were trained to respond under a multiple fixed-interval, fixed-interval schedule in which the first response after 5 min terminated a visual stimulus in the presence of which electric shocks could occur. During one component of the schedule, correlated with one color of stimulus lights, every 30th response also produced electric shock; responding was suppressed during this component to approximately 10 to 12% of that occurring in the alternate component in which responding was not punished. In contrast to previous research, morphine (0.03 to 1.0 mg/kg) increased punished responding. Unpunished responding, however, was either not affected or decreased at doses of morphine that increased punished responding. Increases in rate of punished responding also occurred when the single-schedule punishment condition was studied alone in these animals. Subsequent experimentation, which systematically analyzed the development of the rate-enhancing effects of morphine on punished responding, involved the study of drug effects in additional monkeys trained initially under a single-schedule punishment condition. The effects of morphine on punished responding were studied before, after, and then during exposure to the multiple schedule that included a component in which responding was not punished. Increases in response rate with morphine did not occur until it was administered during exposure to the multiple schedule that included a component in which responding was not punished. As with the other monkeys, once the rate increases in punished responding occurred under the multiple schedule, these effects of morphine persisted, even when the multiple schedule was removed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Timeout as a punishing stimulus in continuous and intermittent schedules

The effectiveness of a brief period of isolation (timeout) in the control of disruptive behavior emitted by a retarded child in a preschool classroom setting was examined. Timeout was shown to be an effective punishing stimulus, and its control of the child's disruptive behavior was investigated under four schedules of intermittent timeout. The results suggest that as a larger percentage of responses were punished, a greater decrease in the frequency of that response occurred. This inverse relationship between the percentage of responses punished and the frequency of the response did not appear to be linear, but rather a non-linear function. This function suggests that some schedules of intermittent punishment may be as effective as continuous punishment, at least in the case of the continued suppression of a response that has already been reduced to a low frequency.     

Implicit task sequence learning with auditory stimuli

We investigated implicit task sequence learning with auditory stimuli. In previous studies only visual stimuli have been used and thus learning may have been due to visuoperceptual learning. Further, we explored the generality of the correlated streams account which holds that correlated streams of information are necessary for implicit sequence learning to occur. We used three classification tasks with auditory stimuli. The presence or absence of a task sequence was orthogonally manipulated with that of a response sequence. Sequence-specific learning was found, but only in the condition with both a task and a response sequence. No learning was found in the conditions with a single task sequence and with a single response sequence. These results show that task–response sequence learning occurs with auditory stimuli and that visuoperceptual learning is not necessary. Moreover, they underscore the importance of correlated streams of information for implicit sequence learning.     

Paleostriatal lesions and instrumental learning in the pigeon

In three experiments, pigeons with lesions of the paleostriatum (experimental subjects) and unoperated control birds were trained on tasks designed to assess their instrumental learning abilities. In Experiment 1, using an orthodox Skinner box, training was given on a variable interval (VI) followed by a fixed interval (FI) schedule of reinforcement and only non-significant differences between the groups emerged. Experiment 2 examined the performance of the same subjects on a VI schedule in which a response-contingent signal accompanied reinforcement. For control subjects the presence of the signal resulted in a low rate of response compared with that found in equivalent conditions with the signal omitted. Experimental subjects showed the same response rate when the signal was present as when it was absent. Experiment 3 employed naive subjects, and a Skinner box modified to facilitate key-pecking in total darkness. In this apparatus, experimental subjects showed a lowered response rate on a VI schedule. These tasks were analyzed in terms of the classical (stimulus-reinforcer) and instrumental (response-reinforcer) learning they involve. The results suggest that pigeons with paleostriatal lesions show a deficit in forming response-reinforcer associations, perhaps because the lesions reduce the salience of response-produced cues.     

Transfer of avoidance responding to a sensory preconditioned cue: Evidence for the role of S-S and R-S knowledge in avoidance learning

In avoidance learning studies, a warning signal (Sd) is directly paired with an aversive unconditioned stimulus (US) unless a particular response is performed. Research by Augustson and Dougher (1997) demonstrated that not only warning signals but also stimuli that are indirectly paired with the aversive event are capable of affecting the avoidance response. In the present study, we extended these results by incorporating a sensory preconditioning paradigm in an avoidance learning procedure. Sensory preconditioning training influenced the selection of avoidance responses in the presence of warning signals that were never paired directly with the aversive events. Moreover, results suggest that the selection of the avoidance responses was based on an integration of knowledge about the relation between the Sd and the US (S-S knowledge) and knowledge about the relation between the avoidance response and the US (R-S knowledge). As the expectancy-based theory of Lovibond (2006) is the only theory of avoidance that incorporates both knowledge structures, the results provide unique support for this theory.     

Motivational aspects of escape from punishment

Punishment and escape were studied simultaneously by allowing a subject to escape from a stimulus situation in which responses were punished, into a stimulus situation in which responses were not punished. The frequency of the punished responses was found to be an inverse function of the intensity of punishment, whereas the frequency of the escape response was a direct function of the intensity of punishment. Both of these functions were obtained under three different schedules of food reinforcement. The strength of the escape behavior was evidenced by (1) the emergence of the escape response even when the frequency of food reinforcement decreased as a consequence of the escape response, (2) the maintenance of the escape response by fixed-interval and fixed-ratio schedules of escape reinforcement, and (3) the occurrence of escape responses at intensities of punishment that otherwise produced only mild suppression of the punished response when no escape was possible. This last finding indicates that a subject may be driven out of a situation involving punishment even though the punishment is relatively ineffective in suppressing the punished responses when no escape is possible.     

Intentional fixation of behavioural learning,or how R-O learning blocks S-R learning

Four experiments deal with the acquisition of knowledge for the control of voluntary behaviour. Subjects had to accomplish a computer-controlled learning task that required them to learn which one of four actions (R) had to be performed in order to attain a certain one of four outcomes (O) in the presence of one of four situational contexts (S). Reinforcements were assigned to actions according to two schedules: In the S-R condition each of the four actions was consistently reinforced in the presence of a certain situation, whereas in the R-O condition each of the actions was either always (Experiments 1-3) or mostly (Experiment 4) reinforced if a certain outcome was required. Furthermore, the type of feedback was varied. In Experiment 1, only positive or negative reinforcements were fed back, whereas in Experiments 2-4 the actions resulted in outcomes that had to be compared with the required outcomes in order to determine successes and failures. The results indicate a preference for learning R-O contingencies over learning S-R contingencies. Most subjects were so fixated on learning R-O relations that they remained completely blind to the consistent reinforcement of S-R mappings. The data suggest that, in line with the ideomotor principle, the acquisition of behavioural competence is based primarily on the formation of bidirectional action-outcome relations. Specifications of the underlying learning mechanisms are discussed.     

Sign tracking in cuttlefish (Sepia officinalis)

Two groups of cuttlefish (Sepia officinalis) were used to demonstrate classical conditioning in this species and to determine whether the resulting approach response would be that of sign tracking or goal tracking. For cuttlefish in the paired condition, a flashing light was presented at one end of a long tank followed by food dropped into the center of the tank. For cuttlefish in the unpaired condition, food was dropped into the center of the tank either before or after the flashing-light stimulus. Paired cuttlefish oriented to the light, positioned themselves within striking distance, and occasionally attacked the light. Unpaired cuttlefish showed no reliable response to either stimulus. The results demonstrate that cuttlefish are capable of signal learning and that, under the conditions tested, cuttlefish sign tracked. This study begins a comparative analysis of learning in cuttlefish and offers a possible ecological advantage for sign-tracking behavior.     

The role of anticipation and intention in the learning of effects of self-performed actions

The anticipative learning model for acquiring action-effect relations states that the acquisition of action-effect relations depends on processes that are part of action planning, in particular the anticipation of possible effects. Experiment 1 shows that response planning is indeed crucial for the learning of response effects. In this experiment distractors (tones) were presented either during response preparation or in the time interval between response execution and the presentation of a response effect. Response-effect learning was impaired when the distractors were presented during response preparation. The finding is consistent with the assumption that the distractors impaired the anticipation of potential effects and therefore reduced effect learning. In Experiment 2 all responses had two effects. Participants were instructed to produce one of the effects. Under this condition, response-effect learning was only found for the instructed effect, not for the non-instructed effect. The two experiments thus support the view that response-effect learning is selective and depends on the anticipation of potential effects during response planning. The results are discussed in terms of a model that explains both the learning of response-effect relations and the use of these effects for action control within the same theoretical framework.     

A choice technique to assess the effects of selective punishment on fixed-ratio performance

The emission of a fixed number of responses by rats was followed by food reinforcement. This fixed number could be accumulated in any way from two continuously available but mutually incompatible response classes, bar pressing, and not bar pressing for a fixed time period. A preference for one response class was arranged by specifying different maximum reinforcement rates for the two classes. Under selective punishment conditions, the preferred response occasionally led to both food and electric shock, while the non-preferred response led only to food. Selective punishment effects were measured through changes in the preference to the two responses in the sequence. The actions of shock intensity, deprivation, the specification of the non-preferred response, and three drugs were investigated. The results were broadly similar to the work reported by Dardano and Sauerbrunn (1964), who found localized increases in interresponse times before punished responses in fixed-ratio schedules. Performance under this procedure was found to be stable and sensitive to each of the experimental variables examined.     

Context blocking in rat autoshaping: Sign-tracking versus goal-tracking

Prior experience of unsignaled food can interfere with subsequent acquisition by birds of autoshaped key-pecking at a signal light. This has been understood to indicate that unsignaled food results in context conditioning, which blocks subsequent learning about the keylight-food relationship. In the present experiment with rats lever insertion as the conditioned stimulus (CS) preceded sucrose delivery as the unconditioned stimulus (US). Half the rats initially received unsignaled USs in the conditioning context, while the remainder did not. Both lever-presses (sign-tracking) and magazine-entries (goal-tracking) were recorded. Under immediate reinforcement conditions, prior unsignaled US interfered with sign-tracking, but had no effect on goal-tracking. In two further groups, a trace condition prevented development of sign-tracking. In this case, prior context conditioning interfered with goal-tracking. These results suggest that interference with sign-tracking may reflect response competition, while interference with goal-tracking under trace conditions may reflect failure to acquire a CS-US association.     

Learning on a response continuum: Comparison of a linear change and a functional learning model

Two reinforcement schedules were used to compare the predictive validity of a linear change model with a functional learning model. In one schedule, termed “convergent,” the linear change model predicts convergence to the optimum response, while in the other, termed “divergent,” this model predicts that a subject's response will not converge. The functional learning model predicts convergence in both cases. Another factor that was varied was presence or absence of random error or “noise” in the relationship between response and outcome. In the “noiseless” condition, in which no noise is added, a subject could discover the optimum response by chance, so that some subjects could appear to have converged fortuitously. In the “noisy” conditions such chance apparent convergence could not occur.The results did not unequivocally favor either model. While the linear change model's prediction of nonconvergence in the divergent conditions (particularly the “noisy” divergent condition) was not sustained, there was a clear difference in speed of convergence, counter to the prediction inferred from the functional learning model. Evidence that at least some subjects were utilizing a functional learning strategy was adduced from the fact that subjects were able to “map out” the relation between response and outcome quite accurately in a follow-up task. Almost all subjects in the “noisy” conditions had evidently “learned” a strong linear relation, with slope closely matching the veridical one.The data were consistent with a hybrid model assuming a “hierarchy of cognitive strategies” in which more complex strategies (e.g., functional learning) are utilized only when the simpler ones (e.g., a linear change strategy) fail to solve the problem.     

Biased feedback in spatial recall yields a violation of delta rule learning

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4° toward the vertical axis (toward condition) or 4° farther away from the vertical axis (away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) produced a stronger experience-dependent change over blocks in the away condition than in the toward condition. This violates delta rule learning. Subsequent simulations of the dynamic field theory of spatial cognition provide a theoretically unified account of these results.     

Punishment-specific effects of pentobarbital: dependency on the type of punisher.

Pigeons were trained to peck a key under a multiple random-interval 1-minute, random-interval 6-minute schedule of food presentation. Subsequently, over three phases, additions were made during the random-interval 1-minute component as follows: pecks during the component occasionally were punished by timeout presentation (Phase 1), timeouts were presented independently of responding during the component (Phase 2), pecks during the component occasionally were punished by electric-shock presentation (Phase 3). In Phases 1 and 3, response-dependent timeout and shock suppressed responding and established equivalent rates in both components of the multiple schedule. Intermediate doses of pentobarbital increased responding suppressed by electric-shock punishment but had little or no effect on responding suppressed by timeout punishment. Response-independent presentation of timeouts did not result in suppression of responding (thus showing that response-dependent timeout acted as a punisher), and pentobarbital did not reliably increase unpunished responding. Pentobarbital's selective "punishment-attenuating" properties depend on the nature of the punisher.