Percentage body weight and the successive negative contrast effect in rats

In two runway experiments employing rats the successive negative contrast effect was evaluated for animals maintained at high or low body weights. In both experiments the effects on performance of shifting reward magnitude were independent of body weight. These results contrast with those of previous studies in which the successive negative contrast effect occurred only under low body weight. It was suggested that when conditions are maximal or near maximal for production of the successive negative contrast effect, as they were here but not in previous investigations, body weight will not influence the size of this effect.     

Spontaneous recovery of consummatory behavior, but not of consummatory successive negative contrast

Five experiments were designed to study spontaneous recovery (SR) in two situations involving consummatory behavior: consummatory successive negative contrast (cSNC) and consummatory extinction (cE). SR of consummatory suppression should occur if incentive downshift induces an egocentric memory encoding information about the emotional reaction to the downshift that is counterconditioned or extinguished during exposure to the downshifted reward. SR of cSNC failed to occur after resting periods of 24, 96, or 336 h interpolated following complete (Experiment 1) and incomplete (Experiment 2) recuperation of consummatory behavior, and was not induced by the opioid-receptor antagonist naloxone (2 mg/kg), known to enhance cSNC (Experiment 3). However, SR of consummatory behavior occurred across sessions in cSNC (Experiment 3) and cE (Experiments 4-5). Furthermore, naloxone facilitated cE without affecting SR (Experiments 4-5). These results are discussed in relation to evidence for the development of an egocentric memory of the aversive downshift experience in consummatory situations.     

Effects of early life and current housing on sensitivity to reward loss in a successive negative contrast test in pigs

Animal Cognition - Animals in a negative affective state seem to be more sensitive to reward loss, i.e. an unexpected decrease in reward size. The aim of this study was to investigate whether...     

Determinants of cumulative successive contrast in saltiness intensity judgments

When all stimuli elicit the same taste quality, solutions preceded by a high concentration level are judged to be significantly less intense than solutions preceded by a low concentration level. After repetitious stimulation with a different tasting stimulus, the intensity of the present stimulus is overestimated. This phenomenon is called “successive contrast.” In the present study, the cumulative effects of three identical stimuli on the saltiness ratings for a test stimulus are investigated. The preceding stimuli are manipulated with regard to taste quality, saltiness intensity, total taste intensity, and complexity. Whether the size of the cumulative contrast effect is associated with the degree of dissimilarity between preceding stimuli and test stimulus, or with the saltiness or total taste intensity of the preceding stimuli, is investigated. The size of the contrast effect depends on the type of preceding stimulus, its intensity, and the type of test stimulus. No association was found with judgments of the degree of dissimilarity between the preceding stimuli and the test stimulus. For nonsalty preceding stimuli, the contrast effects are independent of concentration level. When the preceding stimuli taste at least partly salty, the total intensity appears to determine the size of the contrast for an unmixed salty test stimulus.     

Gaze-following behind barriers in domestic dogs

Although gaze-following abilities have been demonstrated in a wide range of species, so far no clear evidence has been available for dogs. In the current study, we examined whether dogs follow human gaze behind an opaque barrier in two different contexts, in a foraging situation and in a non-foraging situation (food involved vs. food not involved in the situation). We assumed that dogs will spontaneously follow the human gaze and that the foraging context will have a positive effect on dogs’ gaze-following behaviour by causing an expectation in the dogs that food might be hidden somewhere in the room and might be communicated by the experimenter. This expectation presumably positively affects their motivational and attentional state. Here, we report that dogs show evidence of spontaneous gaze-following behind barriers in both situations. According to our findings, the dogs gazed earlier at the barrier in the indicated direction in both contexts. However, as we expected, the context also has some effect on dogs’ gaze-following behaviour, as more dogs gazed behind the barrier in the indicated direction in the foraging situation. The present results also support the idea that gaze-following is a characteristic skill in mammals which may more easily emerge in certain functional contexts.     

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.     

Transfer and non-transfer successive incentive contrast effects in the rat

Recent evidence concerning successive incentive contrast suggests the occurrence of both positive and negative contrast effects under both non-transfer and transfer conditions. There are three types of explanation for these contrast effects, based on frustration theory, sequential theory and adaptation level theory (perceptual accounts). One of the critical experiments favouring perceptual accounts, Collier and Marx (1959), is subject to a number of methodological criticisms. This experiment was repeated, with modifications to take account of these criticisms, and extended to include transfer, as well as non-transfer, conditions. There was no evidence of contrast. In a further experiment using Collier and Marx's procedure with lever pressing and panel pushing, positive and negative, transfer and non-transfer effects were found using Noyes pellets rather than sucrose as reward. It is suggested that these results contribute some support to perceptual accounts of incentive contrast, although no present theory is entirely satisfactory.     

A molecular analysis of multiple schedule interactions: negative contrast

The present experiments investigated the relationship between changes in the relative reinforced interresponse-time distributions and the occurrence of positive and negative contrast in multiple variable-interval—variable-interval and multiple variable-interval—extinction schedules of reinforcement. Experiment I demonstrated that changes in the interresponse-time distributions were consistently correlated with response-rate changes referred to as positive and negative contrast. Corresponding changes in the reinforced interresponse-time distributions suggested that negative contrast resulted as an inductive effect of selectively reinforcing long interresponse times in the altered component at the moment the baseline schedule was reintroduced. Experiment II demonstrated that the magnitude of the negative-contrast effect could be significantly decreased if the altered component schedule was modified in order to prevent the reinforcement of these interresponse times during the first few sessions of baseline recovery. The results supported a proposal that interresponse time—reinforcer relations may act as amplifiers or attenuators of negative contrast.     

Trait reappraisal amplifies subjective defeat, sadness, and negative affect in response to failure versus success in nonclinical and psychosis populations

Perceptions of defeat have been linked to a range of clinical disorders including psychosis. Perceived defeat sometimes increases in response to failure, but the strength of this association varies between individuals. The present research investigated whether trait reappraisal, a thought-focused coping style, amplified response to stressful events. Two studies (Study 1, n = 120 nonclinical participants; Study 2, n = 77 participants with schizophrenia-spectrum disorders) investigated whether trait reappraisal amplified feelings of defeat following an experience of failure versus success. Frequent reappraisers showed the largest increases in subjective defeat after failure versus success in both studies, with nonclinical participants with greater habitual reappraisal also showing larger increases in sadness and general negative affect. Frequent use of reappraisal may confer vulnerability to subjective defeat in response to stressful life events among nonclinical and clinical populations and could be an area for relapse prevention interventions to target.     

Chasing perception in domestic cats and dogs

Animal Cognition - Chasing motion is often used to study the perception of inanimate objects as animate. When chasing interaction and independent motions between two agents are displayed...     

Positive and negative behavioral contrast in the rat

Three groups of rats received either 8, 23, or 53 sessions of multiple variable-interval variable-interval baseline training before being shifted to a multiple extinction variable-interval schedule. The rate of responding during the unaltered component was higher for the groups shifted to multiple extinction variable-interval than for control groups remaining on multiple variable-interval variable-interval (positive contrast). Furthermore, when the multiple variable-interval variable-interval schedule was re-instated, stable negative contrast was found in the groups that had received 23 or 53 baseline sessions, but not for the group that had received only eight sessions. Positive and negative contrast were also demonstrated in the eight and 23-session groups when the multiple extinction variable-interval and multiple variable-interval variable-interval schedules were re-administered in further phases of the experiment. These results suggest that both positive and negative behavioral contrast can be obtained reliably in a species other than the pigeon.     

Deferred imitation and declarative memory in domestic dogs

This study demonstrates for the first time deferred imitation of novel actions in dogs (Canis familiaris) with retention intervals of 1.5 min and memory of familiar actions with intervals ranging from 0.40 to 10 min. Eight dogs were trained using the ‘Do as I do’ method to match their own behaviour to actions displayed by a human demonstrator. They were then trained to wait for a short interval to elapse before they were allowed to show the previously demonstrated action. The dogs were then tested for memory of the demonstrated behaviour in various conditions, also with the so-called two-action procedure and in a control condition without demonstration. Dogs were typically able to reproduce familiar actions after intervals as long as 10 min, even if distracted by different activities during the retention interval and were able to match their behaviour to the demonstration of a novel action after a delay of 1 min. In the two-action procedure, dogs were typically able to imitate the novel demonstrated behaviour after retention intervals of 1.5 min. The ability to encode and recall an action after a delay implies that facilitative processes cannot exhaustively explain the observed behavioural similarity and that dogs’ imitative abilities are rather based on an enduring mental representation of the demonstration. Furthermore, the ability to imitate a novel action after a delay without previous practice suggests presence of declarative memory in dogs.     

Attitudes toward empathy in domestic dogs and cats

This exploratory study included 524 undergraduate students (360 women, M age = 21.1 yr., SD = 6.1; and 164 men, M age = 20.0 yr., SD = 3.6) enrolled in introductory psychology sections who completed the Empathy in Pet Dogs and Cats Scale to assess their attitudes regarding how much domestic dogs and cats show vicarious experiencing of the thoughts, feelings, or attitudes of their owners. A principal components analysis followed by varimax rotation extracted five factors accounting for 60.85% of the total variance as follows: (1) Pets' empathy for owner, (2) Cats' empathy for owner, (3) Dogs' empathy for owner, (4) Souls in humans and pets, (5) Owners' empathy for pets. Women gave significantly higher ratings than men regarding dogs' and cats' knowing when their owners are happy, sad, or angry. Women also gave significantly higher ratings than men regarding dogs' and cats' feeling love and compassion for their owners. Specific instances of empathy in pets underscore the need for contemporary research to be inclusive of operational definitions of measures of empathy.     

认知重评对负性效价的抑制促进条件性恐惧消退

认知重评能有效降低个体对情感刺激的负性情绪体验, 但指导性认知重评在恐惧记忆治疗中效果存在争议。本文将认知重评范式与辨别式条件恐惧反应范式结合, 以效价和US预期值为指标, 探讨指导性认知重评训练对恐惧情绪习得和消退的影响效果。以低认知重评能力个体为被试, 在实验前24 h进行指导性认知重评训练。条件性恐惧任务为期2天, 第一天完成条件性恐惧的习得和消退任务, 第二天完成条件性恐惧的再消退任务。结果显示, 经过重评训练后个体在条件性恐惧任务中的恐惧情绪效价显著较低, 说明认知重评有效降低低认知重评能力个体在急性应激状态下的负性情绪体验。所有被试均成功完成辨别式条件性恐惧的习得和消退任务, 因此重评训练并不削弱个体对危险或者安全信息的辨别能力。但在条件性恐惧的消退过程中, 认知重评指导训练加快了恐惧消退, 且24 h后测得的条件性恐惧程度显著较低, 说明指导性重评提高了条件性恐惧记忆的消退效率, 并减弱了条件性恐惧的消退返回。