Aversive and appetitive electrodermal classical conditioning using pictures as stimuli

The principal goal of this study was to verify whether it was possible to obtain both aversive and appetitive electrodermal classical conditioning, using pictures as conditioned stimuli (CS), and unconditioned stimuli (US). Additionally, we tried to verify whether, as a consequence of such conditioning, diminution of the unconditioned response (UR) was observed. With this aim, IAPS (?International Affective Picture System?) pictures were selected as stimuli. A picture showing a burnt face was used as the aversive US (USav), and a picture showing a scene with erotic content was used as the appetitive US (USap). As the aversive CS (CSav), and appetitive CS (CSap), two images with intermediate values of valence and arousal showing male faces were selected. In the experimental group, 10 CSav/USav and 10 CSap/USap trials were presented. In the control group 10 CSav, CSap, USav, and USap trials were presented in pseudorandom order. Skin conductance response (SCR) elicited by both the CSs and the USs was scored. Results showed aversive conditioning, but neither appetitive conditioning nor UR diminution. Problems to obtain conditioning using pictures as stimuli and possible options to overcome them in future research are discussed.     

Aversive conditioning in the sociopath

Results of two experiments on differential conditioning of the skin conductance (SCR) in sociopaths and normal control subjects are described. In the first experiment it was found that an equal number of sociopaths and control subjects were aware of the conditioning contingency. However, only the normal subjects displayed reliable differential SCR conditioning. Sociopaths showed a dissociation between verbal learning and conditioning of a physiological change. The second experiment examined the differential conditioning of normal subjects and sociopaths in partial remission. The number of aware subjects in the two groups did not differ. Aware subjects in both groups showed differential SCR conditioning. Differential conditioning in sociopaths did not persist over trials as it did in control subjects. A deficiency in ACTH 4–10 as well as neurological dysfunctions were considered possible factors in the etiology of sociopathy. Further research on the relation of neuropeptides to the etiology and treatment of sociopathy is suggested.     

Computational heterogeneity in the human mesencephalic dopamine system

Recent evidence in animals has indicated that the mesencephalic dopamine system is heterogeneous anatomically, molecularly, and functionally, and it has been suggested that the dopamine system comprises distinct functional systems. Identifying and characterizing these systems in humans will have widespread ramifications for understanding drug addiction and mental health disorders. Model-based studies in humans have suggested an analogous computational heterogeneity, in which dopaminergic targets in striatum encode both experience-based learning signals and counterfactual learning signals that are based on hypothetical information. We used brainstem-tailored fMRI to identify mesencephalic sources of experiential and counterfactual learning signals. Participants completed a decision-making task based on investing in markets. This sequential investment task generated experience-based learning signals, in the form of temporal difference (TD) reward prediction errors, and counterfactual learning signals, in the form of “fictive errors.” Fictive errors are reinforcement learning signals based on hypothetical information about “what could have been.” An additional learning signal was constructed to be relatable to a motivational salience signal. Blood oxygenation level dependent responses in regions of substantia nigra (SN) and ventral tegmental area (VTA), where dopamine neurons are located, coded for TD and fictive errors, and additionally were related to the motivational salience signal. These results are highly consistent with animal electrophysiology and provide direct evidence that human SN and VTA heterogeneously handle important reward-harvesting computations.     

Procrastination: Self-regulation in Initiating Aversive Goals

Procrastination is a common phenomenon that is easily recognised as one of the behaviours involved in not doing and avoiding work. However, work motivation theories have not devoted much attention to why people don't do things at work. Just as the study of abnormal behaviour is used to understand normal behaviour, so can the study of procrastination enhance the understanding of self-regulation. In this paper, procrastination is defined as the avoidance of the implementation of an intention. It is characterised by the avoidance of the intention and the preference for behaviour or thoughts that distract from the aversiveness of the intention. Individual difference variables, processes, and conditions are identified. Strategies to overcome procrastination are suggested.     

A delivery system for olfactory stimuli

This paper describes the design of a new method for controlling and administering olfactory stimuli—namely, thehood system. The hood system involves a stream of vaporized odor (at known concentrations) mixed with odorless air and pumped (at a constant flow rate) into an oxygen therapy hood. It is designed to be used with odorants in solution, such as essential oils, as the olfactory stimulus. The use of oxygen therapy hoods allows for the precise control of a constant concentration of odorized air over time, while allowing subjects to breathe normally. The hood system provides a natural administration of olfactory stimuli and the exact determination of the stimulus concentration. The use of this system will allow experimental conditions to be completely defined and results and replication studies to be accurately interpreted. The hood system is portable, cost effective, and constructed from readily available components. It is proposed that the hood system could be adopted to suit a wide range of olfactory research, particularly that in which the effects of chronic exposure to olfactory stimuli on cognition are examined.     

Aversive and positive conditioning treatments of homosexuality

Thirty-one male homosexual patients were randomly allocated to receive either aversive therapy, in which unpleasant shocks were associated with pictures of nude males; or positive conditioning, in which pictures of nude women were associated with similar pictures of men and later with pictures of heterosexual relationships. The patients were further randomly allocated to receive either procedure according to a forward or backward conditioning paradigm. Before, 3 weeks and 1 yr following 5 days of treatment, the patients were shown a film containing at 1-min intervals 10-sec segments of pictures of nude women or men. During this and all treatment procedures their penile volume responses were measured.

The positive conditioning technique proved ineffective and hence acted as a placebo treatment control for the aversive therapy. Patients reported significantly greater reduction in homosexual feelings and behaviour following the latter. After both the aversive and the positive conditioning technique, patients showed significantly less penile volume increase to the pictures of men. There was no trend for this change to be greater following aversive therapy. It was concluded that this therapy reduced the secondary reinforcement value of homosexual stimuli but did not alter sexual orientation.     

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.     

Aversive properties of the negative stimulus in a successive discrimination

Experiment I sought to determine if the stimulus correlated with extinction in a successive discrimination was an aversive stimulus. An escape response provided an index of aversive control. Two groups of pigeons were exposed to a multiple variable-interval 30-sec extinction schedule. For the experimental group, a single peck on a second key produced a timeout during which all lights in the chamber were dark. For the control group, pecks on the second key had no contingency. The rate of responding on the timeout key during extinction for the experimental group was higher than that of the control group during all sessions of discrimination training except the first. In Exp. II, green was correlated with variable interval 30-sec and red was correlated with variable-interval 5-min. Timeouts were obtained from variable-interval 5-min. There were more timeouts from extinction in Exp. I than from variable-interval 5-min in Exp. II. Experiment III showed that not presenting the positive stimulus reduced the number of timeouts from the negative stimulus for the two birds from Exp. I that had the highest rate of timeouts from extinction, but had little effect on the two birds that had the lowest rate of timeouts. These results suggest that in a multiple schedule, the stimulus correlated with extinction, or the lower response rate, functions as a conditioned aversive stimulus. Explanations of the timeout response in terms of extinction produced variability, displaced aggression, and stimulus change, were considered but found inadequate.     

Aversive racism and selection decisions: 1989 and 1999

The present study investigated differences over a 10-year period in whites' self-reported racial prejudice and their bias in selection decisions involving black and white candidates for employment. We examined the hypothesis, derived from the aversive-racism framework, that although overt expressions of prejudice may decline significantly across time, subtle manifestations of bias may persist. Consistent with this hypothesis, self-reported prejudice was lower in 1998–1999 than it was in 1988–1989, and at both time periods, white participants did not discriminate against black relative to white candidates when the candidates' qualifications were clearly strong or weak, but they did discriminate when the appropriate decision was more ambiguous. Theoretical and practical implications are considered.     

Aversive control of self-injurious behavior in a psychotic boy

Two studies are reported which indicate how quickly and effectively chronic self-injurious behavior was controlled in a 9-yr-old blind psychotic boy. In the first study, the self-injurious responses were punished by contingent withdrawal of human physical contact. In the second study, response-contingent electric shock was employed.     

Aversive conditioning,schizotypy, and affective temperament in the framework of the salience hypothesis

During classic conditioning, the processing of conditioned stimuli (CSs+) is enhanced relative to neutral stimuli (CSs−). In patients with psychotic disorders, CSs− become abnormally relevant relative to CSs+, which may lead to the formation of aberrant associations. In this study, we explored how schizotypal and affective personality traits are associated with salience processing in nonclinical individuals. We used aversive conditioning and personality questionnaires in 100 healthy volunteers. The CSs+ were colored circles predicting the unconditioned stimulus (US), which was a loud noise. Circles of another color were the CSs− predicting no US. Conditioning was measured with skin conductance responses (SCRs) and reaction time. Results revealed that higher reality distortion, introvertive anhedonia, and cyclothymic personality negatively correlated with SCRs and positively correlated with reaction time for CSs+, which indicates less efficient conditioning. After taking into account the covariance between these personality traits, only reality distortion and introvertive anhedonia remained significant for CS+ SCRs, and introvertive anhedonia remained significant for CS+ reaction time. Enhanced responses to CSs− were positively predicted only by reality distortion. These results suggest that salience-processing biases are related to schizotypal personality traits in healthy individuals, exhibiting a similar pattern to that observed in psychotic disorders.     

Aversive properties of the negative stimulus during learning with and without errors

In a successive discrimination four groups of pigeons were trained to discriminate between red and green. The groups differed with respect to the procedure used to introduce S?: Early-Progressive, Early-Constant, Late-Progressive, and Late-Constant. The aversive properties of S? were measured by an escape response in which a single peck at a second key terminated S? for 10 sec and darkened the chamber. The correlation between the aversive and error-producing properties of extinction was zero. More errors occurred when S? was introduced abruptly at a constant intensity while more timeouts from S? occurred when S? was introduced late. The procedure for introducing S? rather than the number of responses to S? appears crucial in determining how aversive S? becomes.     

Emotionally Based Expectancies and Willingness To Use Aversive Therapy

Intellectually based expectancies are beliefs about the world that are subjectively perceived as true. Emotionally based expectancies are beliefs that have an "as if" quality to them. The two types of expectancies derive from different sources and are influenced by different variables. This study examined the relationship between these two types of expectancies and willingness to use aversive therapy. Forty-seven undergraduate subjects were first given a brief lecture on childhood autism and the treatment of self-injurious behavior by aversive therapy. Afterwards, they indicated on a brief questionnaire their intellectually and emotionally based expectancies about how effective aversive therapy would be. Finally, they indicated their willingness to use aversive therapy themselves with autistic children. The partial correlation of emotionally based expectancies with stated intentions was .48, that of intellectually based expectancies with stated intentions was .10. As predicted, the emotionally based expectancy correlation was significantly higher.