Contextually Based Conditional Discrimination of the Rabbit Eyeblink Response

Rabbits received conditional discrimination training using contextual stimuli to set the occasion for stimulus pairings during eyelid conditioning. Specifically, animals were exposed to either the presence or the absence of an oscillating chamber light throughout the intertrial interval (50 ± 10 s). For half the animals, this light signaled paired presentations of a discrete tone conditioned stimulus (CS) and air puff unconditioned stimulus (US) while darkness signaled presentations of only the tone CS. The remaining animals experienced the opposite contextual relationship to the conditioning stimuli. These trial types occurred pseudo-randomly across a session, with all transitions between contextual settings (i.e., light or dark) taking place immediately at the CS–US offset. Under these conditions, animals successfully utilized the contextual stimuli as conditional cues for differential responding to the shared CS. Moreover, both light and dark were equally effective as discriminative stimuli. A subset of animals received further training in which the contextual contingency was removed by restricting all conditioning to the CS-alone context. Without the contingency in place, subsequent CS presentations (paired and CS-alone) evoked equivalent conditioned responding across three sessions of training. Following the reinstatement of the contextual contingencies, discriminatory responding was immediately observed and returned to previous levels within three sessions. Finally, animals appeared to use the static representation of the conditional cue, rather than the phasic transition between cues, for discriminatory responding. These findings are discussed in terms of current neurobiological models of eyelid conditioning.     

Counterconditioning of appetitive and defensive CRs in rabbits

Two experiments examined interactions between conditioned appetitive and defensive responses in the rabbit. In Experiment I, a conditioned jaw-movement response was established by following presentations of a clicker CS with intra-oral sucrose delivery on 50% of trials. The jaw-movement response was then maintained on this partial reinforcement schedule during a counterconditioning phase. A group which received para-orbital shock paired with the CS on non-sucrose trials showed acquisition of eyeblink responding and suppression of jaw-movement responding to the CS, in comparison to control groups which received either no shock or unpaired presentations of the CS and shock. Experiment II was identical in design to Experiment I except that the roles of the sucrose and shock reinforcers were reversed. The paired group acquired a conditioned jaw-movement response when sucrose was added in the counterconditioning phase, but in contrast to Experiment I showed a slight enhancement of the previously established eyeblink response. The asymmetry of appetitive and defensive counterconditioning was discussed in relation to opponent-process theories of motivation and reinforcement.     

Acquisition,Extinction, Recovery,and Reversal of Different Response Sequences Under Conditional Control by Nicotine in Rats

Complex voluntary behaviors occur in sequence. Eight rats were trained in an operant procedure that used nicotine and non-drug (saline) states as interoceptive cues that signaled which of two behavioral sequences led to food reward. The distal and proximal responses in the chain were always maintained on variable interval 30-sec and fixed ratio-1 schedules, respectively, and rate differences between the responses were used as the dependent variable. Extinction and reversal training was conducted. Distal response rates were significantly greater than proximal response rates during training, testing, extinction, and reversal learning. These data suggest that (a) nicotine can establish interoceptive control over different response sequences, and (b) extinction of one response sequence may be state-dependent. The clinical relevance of extinction of complex behavioral repertoires such as drug-seeking and drug-taking behavior that are evoked by specific interoceptive cues is addressed in regard to drug abuse treatment and relapse.     

Counterconditioning in the treatment of spider phobia: effects on disgust, fear and valence

From the perspective that disgust is a core feature of spider phobia, we investigated whether the treatment efficacy could be improved by adding a counterconditioning procedure. Women with a clinically diagnosed spider phobia (N = 34) were randomly assigned to the regular one-session exposure condition (EXP) or to the exposure with counterconditioning condition (CC). In the CC-condition tasty food-items were used during the regular exposure exercises and the participants' favourite music was played. Both treatment conditions appeared very effective in reducing avoidance behaviour and self-reported fear of spiders, strongly attenuated the disgusting properties of spiders and altered the affective evaluations in a positive direction. CC was not more effective in altering the affective valence of spiders than EXP and was not superior with respect to the long term treatment efficacy at 1 year follow up. Apparently, regular exposure treatment is already quite effective in altering the affective-evaluative component of spider phobia and it remains to be seen whether it is possible to further improve treatment outcome by means of procedures which are specifically designed to reduce the spiders' negative affective valence.     

Control by Contextual Stimuli in Novel Second-Order Conditional Discriminations

The Psychological Record - Eighteen undergraduates participated in studies designed to examine the factors that produce transfer of contextual functions to novel stimuli in second-order conditional...     

Counterconditioning and exposure-only in the treatment of specific (conditioned suppression) and generalized fear in rats

In Experiment 1 the conditioned suppression technique was used to condition specific fear, suppression of operent lever pressing for food to a discrete CS. The efficacy of four treatment conditions on fear reduction was evaluated. Counterconditioning in which exposure to the CS was contiguously paired with food was significantly less effective than noncontiguous CS exposure and food. An exposure-only effect was indicated by the superiority of all three treatments involving CS exposure (the above two plus a typical conditioned suppression extinction procedure) to treatment consisting of food only. The reverse counterconditioning effect and the exposure effect are consistent with current views that emphasize the centrality of aversive stimulus exposure in fear reduction. Experiment 2 investigated elimination of generalized fear produced by unsignalled, inescapable shocks in the lever-pressing apparatus. Two treatments (counterconditioning and exposure-only) were equally effective and they were superior to no exposure control treatment. The results of the two experiments reinforce recent attempts toward a reevaluation of the role of anxiety-competing responses in elimination of fear.     

Conditional discrimination and equivalence relations: Control by negative stimuli

Three adult subjects were taught the following two-sample, two-comparison conditional discriminations (each sample is shown with its positive and negative comparison, in that order): A1-B1B2, A2-B2B1; B1-C1C2, B2-C2C1; and C1-D1D2, C2-D2D1. A teaching procedure was designed to encourage control by negative comparisons. Subjects were then tested for emergent performances that would indicate whether the baseline conditional discriminations were reflexive, symmetric, and transitive. The tests documented the emergence of two classes of equivalent stimuli: A1, B2, C1, D2 and A2, B1, C2, D1. These were the classes to be expected if the negative comparisons were the controlling comparisons in the baseline conditional discriminations. The negative comparisons, however, were not the comparisons that subjects were recorded as having chosen in the baseline conditional discriminations. Differential test results confirmed predictions arising from a stimulus-control analysis: In reflexivity tests (AA, BB, CC, DD), subjects chose comparisons that differed from the sample; one-node transitivity (AC, BD) and "equivalence" (CA, DB) tests also yielded results that were the opposite of those to be expected from control by positive comparisons; symmetry tests (BA, CB, DC), two-node transitivity (AD) tests, and two-node "equivalence" (DA) tests yielded results that were to be expected from control by either positive or negative comparisons.     

Differential Mastication Kinematics of the Rabbit in Response to Food and Water: Implications for Conditioned Movement

Analysis of naturalistic chewing patterns may provide insight into mapping the neural substrates of jaw movement control systems, including their adaptive modification during the classically conditioned jaw movement (CJM) paradigm. Here, New Zealand White rabbits were administered food and water stimuli orally to evaluate the influence of stimulus consistency on masticatory pattern. Chewing patterns were recorded via video camera and movements were analyzed by computerized image analysis. The mandibular kinematics, specifically the extent of dorsal/ventral, medial/lateral, and rostral/caudal movement, were significantly larger in food-evoked than water-evoked chewing. Water-evoked chewing frequency, however, was significantly higher than that of food-evoked movements. In light of known cortical mastication modulatory centers, our findings implicate different neural substrates for the responses to food and water stimuli in the rabbit. A detailed delineation of jaw movement patterns and circuitry is essential to characterize the neural substrates of CJM.     

The Effect of Counterconditioning on Evaluative Responses and Harm Expectancy in a Fear Conditioning Paradigm

In fear conditioning, extinction targets harm expectancy as well as the fear response, but it often fails to eradicate the negative affective value that is associated with the conditioned stimulus. In the present study, we examined whether counterconditioning can serve to reduce evaluative responses within fear conditioning. The sample consisted of 70 nonselected students, 12 of whom were men. All participants received acquisition with human face stimuli as the conditioned stimuli and an unpleasant white noise as the unconditioned stimulus. After acquisition, one third of the sample was allocated to an extinction procedure. The other participants received counterconditioning with either a neutral stimulus (neutral tone) or a positive stimulus (baby laugh). Results showed that counterconditioning (with both neutral and positive stimuli), in contrast to extinction, successfully reduced evaluative responses. This effect was found on an indirect measure (affective priming task), but not on self-report. Counterconditioning with a positive stimulus also tended to enhance the reduction of conditioned skin conductance reactivity. The present data suggest that counterconditioning procedures might be a promising approach in diminishing evaluative learning and even expectancy learning in the context of fear conditioning.     

Statistical Tests of Conditional Independence Between Responses and/or Response Times on Test Items

Three plausible assumptions of conditional independence in a hierarchical model for responses and response times on test items are identified. For each of the assumptions, a Lagrange multiplier test of the null hypothesis of conditional independence against a parametric alternative is derived. The tests have closed-form statistics that are easy to calculate from the standard estimates of the person parameters in the model. In addition, simple closed-form estimators of the parameters under the alternatives of conditional dependence are presented, which can be used to explore model modification. The tests were applied to a data set from a large-scale computerized exam and showed excellent power to detect even minor violations of conditional independence.     

Obligation and the Conditional in Stit Theory

In this paper, we consider two different ways in which modus-ponens type reasoning with conditional obligations may be formalized. We develop necessary and sufficient conditions for the validity of each, and make some philosophical observations about the differences between the minor premises that each formalization requires. All this is done within the context of the Belnap-Perloff stit theory.     

Conditional Reactions in the Rat

To assess the effects of the presence of the experimenter (E) and/or modelrewarder (MR), elementary school children observed a model emit specific sequences on a button pressing task in two separate experiments (N = 50 and N = 80). The first design was a 2 × 2 factorial involving the presence-absence of the E/MR and model reward vs. model no-consequences; the second design was a 4 × 2 factorial with all possible combinations of presence-absence of the E and/or MR, and model reward vs. model no-consequences. It was found that model reward increased imitation only in the condition in which the E was present and the MR was absent.     

Shaking That Icky Feeling: Effects of Extinction and Counterconditioning on Disgust-Related Evaluative Learning

Learned disgust appears to play an important role in certain anxiety disorders, and can be explained by the process of evaluative conditioning, in which an affective evaluative reaction evoked by an unconditional stimulus (US) is transferred to a conditional stimulus (CS). Much remains unknown about how disgust-related evaluative learning can be effectively eliminated. Study 1 of the present investigation examined the effects of extinction on reducing the negative evaluation of a CS that was acquired during disgust conditioning. Participants completed acquisition trials, with a disgusting picture as US and two neutral pictures as CS (CS + was paired with the US; CS- was unpaired), followed by extinction trials ("CS only"; experimental condition) or a filler task (control condition). Extinction trials reduced acquired US expectancy to the CS +, but did not extinguish negative evaluations of the CS +. Study 2 examined the effects of counterconditioning on evaluative learned disgust. After disgust acquisition trials, counterconditioning trials followed in which the CS + was paired with a pleasant US (experimental condition) or a filler task (control condition). Counterconditioning trials reduced acquired US expectancy to the CS + and reduced evaluative conditioned disgust. Implications of the potential differential effects of extinction and counterconditioning on evaluative learning for exposure-based treatment of specific anxiety disorders are discussed.     

Establishing Transfer of Compound Control in Children: A Stimulus Control Analysis

The Psychological Record - Five-year-old children received training on four symbolic match-to-sample tasks with single-element stimuli (A1-B1, A2-B2; P1-Q1, P2-Q2). Then they received training on...     

Response Conflict and Affective Responses in the Control and Expression of Race Bias

Models of racial attitudes traditionally have assumed that individual differences in the strength of underlying, 'implicit' associations between racial categories and stereotypical traits are the primary determinant of the expression of race bias. Thus, individual differences in performance on laboratory tasks designed to assess implicit race bias tend to be interpreted in terms of association strength. Here, we argue that such associations tell only part of the story, and probably the least interesting part. We posit that response conflict and its regulation are critical to understanding the need for control, and that affect-related processes help to determine the extent to which control resources will be implemented to overcome biased associations. We present data from a number of recent behavioral and psychophysiological studies in support of this idea, as well as conceptual accounts that point toward a model of race bias regulation that depends upon processes identified as important for regulation of thought, affect and action more generally.     

Conditional discrimination learning in the pigeon

Four pigeons received conditional discrimination training in which reinforcement contingencies were related to specific combinations of color and form, but were unrelated to either color or form considered separately. During discrete-trial training, each response in the presence of two of four color-form displays produced reinforcement and terminated the trial; responding to the other two displays was never reinforced, and each such response prolonged the particular trial on which it occurred. Subsequently, the subjects received multiple-schedule training in which responding to either of the displays previously associated with reinforcement was now reinforced on a variable-interval schedule, and extinction was the schedule again correlated with the other two displays. After differential responding to the stimuli was clearly evident, intensity of the combination displays was changed in subsequent training sessions. Complex stimulus control was generally maintained across variation in intensity, although there were temporary disruptions in performance associated with onset of some of the intensity changes. Finally, a component-stimulus test revealed considerably more responding to the forms than to the colors.