The organization and temporal properties of appetitive behavior in rats

In the presence and absence of an externalinterfood clock stimulus (a sequence of flashing lights), rats showed a multimodal behavior pattern during successive quarters of interfood intervals (IFI) ranging from 12 to 192 sec. Responses near the feeder peaked before and just after food presentations, whereas locomotion remote from the feeder peaked toward the middle of the IFI. The temporal patterns of nosing in the feeder and remote locomotion were scalar (the time at which a response peaked in the IFI was proportional to the IFI length), whereas the patterns of postfood feeder-directed behavior, rearing, and pawgrooming were time bound (peaking at a fixed time after food, regardless of IFI length). Responses varied in their control by the external clock stimulus. During the last half of the IFI, rats nosed in the feeder more with an external clock, but only at intermediate IFIs. During the first quarter of the IFI, rats pawgroomed more with an external clock, but only at the longest IFI. The general sequence of responses during the interfood clock was consistent with the view that food delivery engages an organized sequence of search states that are expressed through a variety of responses.     

Facilitation of appetitive conditioning with naturalistic conditioned stimuli: CS and US factors

Adding limited female cues to a conditioned stimulus (CS) facilitates conditioned male sexual responding. In two experiments, we examined the mechanisms of this facilitation effect. The color of the female cues on the CS was varied in Experiment 1. Similarity between the CS plumage color and the color of the live female (the unconditioned stimulus [US]) could only partially account for the results. The extent to which the facilitation effect represents a specialization of sexual behavior was examined in Experiment 2 by comparing conditioning with either food or copulation as the US. The CSs with female cues elicited more approach and grab responses regardless of which US was used. However, uniquely sexual conditioned responses (mounts and cloacal contacts) were enhanced only when sexual reinforcement served as the US. These findings suggest that the facilitation effect of female cues represents a general feature of appetitive behavior systems.     

The effects of separate presentations of the US on conditioned suppression

Four experiments examined the effects of separate presentations of shock on conditioned suppression of instrumental responding evoked by a CS previously paired with shock. Experiment 1 showed that conditioned suppression of responding resulting from noise-shock pairings increased as a function of time after the initial noise-shock pairings. However, it also showed that this time-dependent increase in conditioned suppression of responding could be attenuated by presentations of light-shock pairings immediately prior to the test of the noise CS. Experiment 2 showed that this attenuation effect can be produced by presentations of either light-shock pairings or shock alone. Experiment 3 showed that the magnitude of this attenuation effect was directly related to the temporal proximity of the light-shock pairings to the test of the noise CS. Experiment 4 showed that the magnitude of this attenuation effect was inversely related to the intensity of separate shock presentations.     

Dissociation of conditioned appetitive and consummatory sexual behavior: Satiation and extinction tests

Sexual responses were conditioned in male Japanese quail using the opportunity to copulate with a female as the unconditioned stimulus (US). The conditioned stimulus (CS) was a 3-D object made of a taxidermically prepared female quail head mounted on a terry-cloth body. Both appetitive conditioned responses (approach and proximity to the CS) and consummatory conditioned responses (mount and cloacal contact directed toward the CS) developed when 2-min presentations of the CS were followed immediately by the US, but not when the CS and US were separated by trace intervals of 10 or 20 min (Experiment 1). Postconditioning sexual satiation suppressed conditioned cloacal contact responses more than conditioned approach to the CS (Experiment 2), and “acute” extinction suppressed both conditioned mounting and conditioned cloacal contact responses more than conditioned approach to the CS (Experiment 3). These results demonstrate a functional dissociation between conditioned appetitive and consummatory responses and imply that the motivational and/or associative mechanisms underlying the two types of behavior are distinct.     

Divergence of conditioned eyeblink and conditioned fear in backward Pavlovian training

Two experiments of Pavlovian conditioning with rabbits evaluated the effects of initiating or continuing a conditioned stimulus (CS) after a paraorbital unconditioned stimulus (US). In Experiment 1, backward pairings, in which a CS came on after the US, produced a CS that appeared inhibitory on a measure of eyeblink conditioning but excitatory on a potentiated-startle measure of conditioned fear. In Experiment 2, extending the duration of a CS that came on prior to the US, so that it continued after the US, decreased eyeblink conditioned responses, whereas it increased conditioned fear. The data from the two experiments confirm and extend those of Tait and Saladin (1986), supporting the suppositions of AESOP (Wagner & Brandon, 1989) that conditioned eyeblink and conditioned fear can be dissociated under various temporal relationships between the CS and US.     

Effects of the correlation between a positive and negative US on conditioned suppression in rats

For three groups of rats, an auditory CS, presented while the animals were responding on a variable-interval schedule for food reinforcement, was terminated on half of the trials with a noncontingent footshock. For two groups, half of the trials were also followed after 5 sec by the delivery of free food. In the positively correlated condition (PC) the free food was presented on shocked trials and in the negatively correlated condition (NC) on the nonshocked trials, while the remaining group (S) never received free food. In a fourth group the shock was omitted and free food delivered on half of the trials. Although all shocked groups showed a significant suppression, the magnitude was greater for Group PC than for Groups NC and S, which did not differ. Suppression did not result from the pairing of the CS with food alone. These results do not support the counterconditioning hypothesis that the pairing of a normally noxious stimulus with food reduces its aversiveness.     

Dissociation of the blocking of conditioned eyeblink and conditioned fear following a shift in US locus

Two experiments with rabbits investigated the concordance of two measures of conditioning, eyeblink and potentiated startle, during a blocking sequence with paraorbital shock reinforcement. In both, a shift in the locus of shock from one eye to the other between the conditioning of an element and a compound of that element and a new cue had differential effects on the two measures of conditioning to the new cue. When the shock was unchanged, diminished conditioning in relation to controls (i.e., blocking) was observed on both measures. When the shock was changed, little conditioning was observed in startle, but control-equivalent amounts were observed in eyeblink (i.e., blocking occurred on the former but not the latter). The results are interpreted as showing a dissociation of the associative learning involving the emotive features of Pavlovian reinforcers and that involving the remaining sensory-perceptual features, and more compatible with a diminished US-processing, than with a CSprocessing, view of blocking.     

定性实验与定量实验的区别及应用

从实验结果的性质进行分类,实验可分为定性实验和定量实验。定性实验是判断研究对象具有哪些性质,并判断某种物质的成分、结构或鉴别某种因素是否存在以及某些因素之问是否具有某种关系的一种实验方法。其特点是回答“有没有”或者“是不是”等问题。这种实验在中学教材中很普遍。定量实验是研究对象的性质、组成和影响因素之间的数量关系。     

The effects of Pavlovian CSs on two food-reinforced baselines— with and without noncontingent shock

Two experiments explored the effects of Pavlovian (tone-shock) CS+, CS?, and truly random control (TRC) contingencies on two different food-reinforced instrumental baselines. One food-reinforced baseline contained noncontingent shock, while the other did not. In the first experiment, a TRC contingency was shown to produce suppression of food-reinforced responding, while a CS? contingency did not. When noncontingent shock was added to the baseline, however, the TRC stimuli failed to produce suppression, and the CS? contingency increased response rates over baseline level. In a second experiment, the effects of TRC and CS+ contingencies were compared on these same two baselines. While the CS+ produced suppression on both shock and no-shock baselines, the TRC contingency again produced suppression on only the no-shock baseline.     

Transient variations in responding to Pavlovian conditioned stimuli have implications for the mechanisms of “priming”

Conditioned responding to a well-trained conditioned stimulus (CS) was assessed in an eyelid conditioning situation under three conditions of prior stimulation: when preceded by recent presentation of the same CS, when preceded by recent presentation of a different CS, and when preceded by no recent stimulation. As compared to the latter condition, prior presentation of the same CS depressed responding, while prior presentation of a different CS augmented responding. Both effects diminished as the interval separating the test stimulus from the preceding CS was lengthened over the range of 2.5 to 10 sec. The results were discussed in terms of the interaction of short-term memory representations with subsequent stimulation, and a specific theory concerning the effects of “priming.”     

Classically conditioned tail flexion in rats: CR-contingent modification of US intensity as a test of the preparatory response hypothesis

A classically conditioned tail flexion in rats with a white noise as the conditioned stimulus and a tailshock as the unconditioned stimulus is shown to arise as a result of contingent presentation of the two stimuli rather than from sensitization or pseudoconditioning. After achieving an asymptote for conditioned tail flexion, different groups received response-contingent tail-shock increment, decrement, or omission. None of these treatments appreciably altered the probability of a conditioned response. Evidence is presented demonstrating that the response was sensitive to changes in the relationship between the stimuli and that the subjects could differentiate the various shock levels. The present data are viewed as inconsistent with the preparatory response hypothesis, which posits that classically conditioned behavior depends upon intrinsic reinforcement of components of the conditioned response syndrome. The possibility is discussed that classically conditioned responses observed in the laboratory are often only part of a larger, perhaps more clearly instrumental, set of behaviors that would occur in the unrestrained animal.     

The impact of individual forms of childhood maltreatment on health behavior

OBJECTIVE: This study examines the unique contribution of five types of maltreatment (sexual abuse, physical abuse, emotional abuse, physical neglect, emotional neglect) to adult health behaviors as well as the additive impact of exposure to different types of childhood maltreatment. METHOD: Two hundred and twenty-one women recruited from a VA primary care clinic completed questionnaires assessing exposure to childhood trauma and adult health behaviors. Regression models were used to test the relationship between childhood maltreatment and adult health behaviors. RESULTS: Sexual and physical abuse appear to predict a number of adverse outcomes; when other types of maltreatment are controlled, however, sexual abuse and physical abuse do not predict as many poor outcomes. In addition, sexual, physical, and emotional abuse and emotional neglect in childhood were all related to different adult health behaviors. The more types of childhood maltreatment participants were exposed to the more likely they were to have problems with substance use and risky sexual behaviors in adulthood. IMPLICATIONS: The results indicate that it is important to assess a broad maltreatment history rather than trying to relate specific types of abuse to particular adverse health behaviors or health outcomes.     

The use of quantitative and qualitative methods in the analysis of academic achievement among undergraduates in Jamaica

This paper describes a study which uses quantitative and qualitative methods in determining the relationship between academic, institutional and psychological variables and degree performance for a sample of Jamaican undergraduate students. Quantitative methods, traditionally associated with the positivist paradigm, and involving the counting and measurement of events and statistical analysis of a body of numerical data, constitute the primary research approach to this investigation. At the same time, qualitative methods are also employed to enhance the contextual meaning and to provide insight into the quantitative-based findings. Full account is taken of concerns relating to paradigmatic violations – that of the positivist and interpretivist in particular – and relevant literature is used to carve a clearer path towards an understanding and reconciliation of combining quantitative and qualitative methods. Further, implications for the findings as they relate to mixed-method design and institutional direction are discussed.     

Context effects on conditioning,extinction, and reinstatement in an appetitive conditioning preparation

Three experiments with rat subjects examined the effects of contextual stimuli on performance in appetitive conditioning. A 10-sec tone conditioned stimulus (CS) was paired with a food-pellet unconditioned stimulus (US); conditioning was indexed by the observation of headjerking, a response of the rat to auditory stimuli associated with food. In Experiment 1, a context switch following initial conditioning did not affect conditioned responding to the tone; however, when the response was extinguished in the different context, a return to the original conditioning context “renewed” extinguished responding. These results were replicated in Experiments 2 and 3 after equating exposure to the two contexts (Experiment 2) and massing the conditioning and extinction trials (Experiment 3). The results of Experiment 1 also demonstrated that separate exposure to the US following extinction reinstates extinguished responding to the tone; this effect was further shown to depend at least partly on presenting the US in the context in which testing is to occur (Experiments 2 and 3). Overall, the results are consistent with previous data from aversive conditioning procedures. In either appetitive or aversive conditioning, the context may be especially important in affecting performance after extinction.     

个体差异中的动机因素对二语习得的影响

个体差异是客观存在的个体因素,个体差异因素中包括认知风格、个体智商、学习动机、学习风格和学习策略等等个体差异因素,其中最主要的还是学习动机。而这一因素在很大程度上影响着第二语学得,对英语的教学也起着至关重要的作用。该文主要论述的是国内外对动机类型,动机对第二外语习得影响的研究以及激励学习动机的策略。     

Gender Differences in the Experience of Higher Education: quantitative and qualitative approaches

This paper reviews the evidence for differences between men and women in their experience of higher education. It is generally agreed that students manifest a number of different approaches to learning, and these have been operationalised in terms of quantitative measures derived from responses to formal questionnaires. Nevertheless, there is little consistent or valid evidence for gender differences in the responses to these instruments. Other researchers have used qualitative methodologies in order to identify different stages of intellectual development among students in higher education. Their findings indicate the existence of parallel, but distinct developmental schemes in male and female students.     

On the generality of conditioned bradycardia in rabbits: Assessment of CS and US modality

To determine whether the magnitude of heart rate (HR) slowing induced by classical conditioning contingencies is comparable under a broad range of stimulus conditions, experiments were conducted in which rabbits were exposed to tones, increases in illumination, or vibratory stimuli as conditioned stimuli (CSs) and in which paraorbital electric shocks, corneal airpuffs, or intraoral pulses of water served as unconditioned stimuli (USs). The results indicated that conditioned bradycardia was elicited by all three CSs. Moreover, when a corneal airpuff served as the US, small but reliable CS-evoked HR decelerations also occurred. Finally, CS-evoked HR slowing also occurred in response to a tone CS employed in an appetitive task, in which water was the US. These findings suggest that HR slowing is a general phenomenon that occurs when rabbits are exposed to signals that systematically predict aversive or appetitive consequences according to a Pavlovian conditioning paradigm.     

幼儿行为问题家庭成因的个案研究

幼儿的行为问题一般是指对身心健康发展有重要障碍的行为和情绪方面的异常表现。弗洛依德的儿童精神发展理论告诉我们,０～６岁是一个人性格行为形成发展的重要阶段,如果在这个阶段,儿童身心需要都得到满足和受到父母良好的教养,儿童就会成为人格健全的人,否则,儿童可能会出现行为障碍、人格缺陷等问题。０～６岁时期,家庭是幼儿主要的生活环境,父母是幼儿接触最多的人,所以家庭因素在幼儿行为问题发生中起着最直接和最重要的作用。尽管幼儿行为问题产生的原因十分复杂,既有幼儿自身的生理和心理特质的原因,也有幼儿园和社会等方…     

The overshadowing of background stimuli by an informative CS in aversive Pavlovian conditioning with rats

Two experiments investigated the capacity of a nominal CS to overshadow background stimuli. Rats received CS-shock pairings in one compartment of a double-compartment apparatus. After training, the shock compartment was re-presented but in the absence of both the CS and shock, and overshadowing was assessed by measuring the rats’ latency to enter the compartment. In the first experiment, predictive values of temporal cues provided by CS onset and CS offset were manipulated. Rats readily entered the shock compartment, provided shock onset had previously been predicted by CS onset or CS offset. This indicates that background cues in the shock compartment had acquired little associative strength during training. In contrast, rats avoided the shock compartment under every condition in which shock onset had not previously been predicted by either CS onset or CS offset. In the second experiment, a precise temporal cue provided by CS onset was dissociated from other factors arising from CS-shock contiguity. It was found that rats’ reactions to the shock compartment after training was governed by both temporal and contiguity factors. The results are relevant to theories which state that conditioning is a function of a competitive relationship between stimuli present in an animal’s environment during training.