Occasional reinforced responses during extinction can slow the rate of reacquisition of an operant response

Three experiments with rats examined reacquisition of an operant response after either extinction or a response-elimination procedure that included occasional reinforced responses during extinction. In each experiment, reacquisition was slower when response elimination had included occasional reinforced responses, although the effect was especially evident when responding was examined immediately following each response-reinforcer pairing during reacquisition (Experiments 2 and 3). An extinction procedure with added noncontingent reinforcers also slowed reacquisition (Experiment 3). The results are consistent with research in classical conditioning (Bouton, M. E., Woods, A. M., & Pineño, O. (2004). Occasional reinforced trials during extinction can slow the rate of rapid reacquisition. Learning & Motivation, 35, 371-390) and suggest that rapid reacquisition after extinction is analogous to a renewal effect that occurs when reinforced responses signal a return to the conditioning context. Clinical implications are also discussed.     

Transformation of the discriminative and eliciting functions of generalized relational stimuli

In three experiments, match-to-sample procedures were used with undergraduates to establish arbitrary relational functions for three abstract visual stimuli. In the presence of samples A, B, and C, participants were trained to select the smallest, middle, and largest member, respectively, of a series of three-comparison arrays. In Experiment 1, the B (choose middle) stimulus was then used to train a steady rate of keyboard pressing before the A (choose smallest) and the C (choose largest) stimuli were presented. Participants pressed slower to A and faster to C than to B. Then B was paired with mild shock in a Pavlovian procedure with skin conductance change as the dependent variable. When presented with A and C, 6 of 8 experimental participants showed smaller skin conductance changes to A and larger skin conductance changes to C than to B. In Experiment 2, A was then used as a sample in a match-to-sample procedure to establish an arbitrary size ranking among four same-sized colored circle comparisons. One of the middle circles was then used to establish a steady rate of pressing before the other circles were presented. Five of 6 participants responded slower to the "smaller" circle and faster to the "larger" circle than they did to the "middle" circle. In Experiment 3, A, B, and C were then presented on a series of test trials requiring participants to pick the comparison that was less than, greater than, or equal to the sample. Novel stimuli were included on some trials. Results indicated that the relational training procedures produced derived relations among the stimuli used in training and that these allowed correct inferences of relative size ranking among novel stimuli.     

Generalisation of fear and avoidance along a semantic continuum

Directly conditioned fear and avoidance readily generalises to dissimilar but conceptually related stimuli. Here, for the first time, we examined the conceptual/semantic generalisation of both fear and avoidance using real words (synonyms). Participants were first exposed to a differential fear conditioning procedure in which one word (e.g., “broth”; CS+) was followed with brief electric shock [unconditioned stimulus (US)] and another was not (e.g., “assist”; CS–). Next, an instrumental conditioning phase taught avoidance in the presence the CS+ but not the CS–. During generalisation testing, synonyms of the CS+ (e.g., “soup”; GCS+) and CS– (e.g., “help”; GCS–) were presented in the absence of shock. Conditioned fear and avoidance, measured via skin conductance responses, behavioural avoidance and US expectancy ratings, generalised to the semantically related, but not to the semantically unrelated, synonyms. Findings have implications for how natural language categories and concepts mediate the expansion of fear and avoidance repertoires in clinical contexts.     

Emotional Valence Precedes Semantic Maturation of Words: A Longitudinal Computational Study of Early Verbal Emotional Anchoring

We present a longitudinal computational study on the connection between emotional and amodal word representations from a developmental perspective. In this study, children's and adult word representations were generated using the latent semantic analysis (LSA) vector space model and Word Maturity methodology. Some children's word representations were used to set a mapping function between amodal and emotional word representations with a neural network model using ratings from 9-year-old children. The neural network was trained and validated in the child semantic space. Then, the resulting neural network was tested with adult word representations using ratings from an adult data set. Samples of 1210 and 5315 words were used in the child and the adult semantic spaces, respectively. Results suggested that the emotional valence of words can be predicted from amodal vector representations even at the child stage, and accurate emotional propagation was found in the adult word vector representations. In this way, different propagative processes were observed in the adult semantic space. These findings highlight a potential mechanism for early verbal emotional anchoring. Moreover, different multiple linear regression and mixed-effect models revealed moderation effects for the performance of the longitudinal computational model. First, words with early maturation and subsequent semantic definition promoted emotional propagation. Second, an interaction effect between age of acquisition and abstractness was found to explain model performance. The theoretical and methodological implications are discussed.     

Appetitive learning using visual conditioned stimuli in the pond snail, lymnaea

Feeding can be conditioned in the pond snail Lymnaea stagnalis to two different visual stimuli (a black panel or a 5-mm black and white check surround) by pairing the potential conditioned stimulus (CS) with sucrose. Exclusion of chemical cues (associated with differences between the water in home tank and that in training apparatus) that could serve as CS is important for successful visual conditioning. A featureless gray surround, used as an alternative to the check (to which it was matched in luminance) in counterbalanced training designs, was discriminated from the check, showing that resolution (for which the eyes would be necessary) was occurring. The gray surround was largely ineffective as a CS. Single-trial learning was possible with the black panel, but not with the check; it is argued that this may be due to lack of prior experience of stimuli like the check. Conditioning of feeding has now been obtained in Lymnaea to chemical, tactile, and visual cues, opening the way to comparative studies of the neural circuitry underlying appetitive conditioning in different senses, so far explored in Lymnaea only for tactile CS. Such comparative studies are as yet largely lacking in invertebrates.     

The effect of comparative context on evaluative conditioning

Evaluative conditioning (EC) is a change in the evaluation of a stimulus after the stimulus co-occurred with affective stimuli. The present research examined whether EC of one stimulus depends also on the co-occurrence of another stimulus with positive or negative stimuli. We paired two target people with affective stimuli. We found that a person who appeared eight times with positive stimuli and eight times with negative stimuli was liked more when the other person appeared always (16 times) with negative stimuli than when the other person appeared always with positive stimuli. The manipulation did not change the US evaluation or the general standard on the value dimension of what a positive or negative stimulus is. We suggest that like other evaluative traits (e.g., evil, pretty) co-occurrence with affective stimuli is sensitive to temporary standards. The manipulation changed the standard of what co-occurrence with affective stimuli is considered positive versus negative.     

Changing likes and dislikes through the back door: The US-revaluation effect

US-revaluation refers to the observation that subsequent changes in the valence of an unconditioned stimulus (US) after pairing it with a neutral, conditioned stimulus (CS) also changes the valence of the associated CS. Experiment 1 found evidence for the US-revaluation effect using an unobtrusive measure of evaluation. However, US-revaluation effects were more pronounced for positive-to-negative compared to negative-to-positive revaluations. Experiment 2 replicated this finding for self-reported evaluations, further showing that US-revaluation effects are stable over time and independent of explicit memory for the revaluating information. Using a modified paradigm, Experiment 3 ruled out method-related explanations for these findings and showed that changes in CS evaluations are correlated with parallel changes in US evaluations. These findings encourage the view of evaluative conditioning as an instance of stimulus–stimulus (S–S) rather than stimulus-response (S–R) learning. Implications for basic and applied research are discussed.     

Hating the cute kitten or loving the aggressive pit-bull: EC effects depend on CS–US relations

Evaluative conditioning (EC) refers to valence changes of initially neutral stimuli (CSs) through repeated pairings with positive or negative stimuli (USs). The current study is about the moderating role of qualifiers that specify the CS–US relation during these pairings. We show successful EC with pictures of men (CSs) and of liked/disliked animals or landscapes (USs). More importantly, the same pairings resulted in standard and reversed EC effects depending on semantic qualifier of the CS–US relation. CSs loving positive (negative) USs became more positive (negative), while CSs loathing positive (negative) USs became more negative (positive). These data favour a propositional EC account (De Houwer, 2009) over a purely associative account, as they show that it is not only relevant that CS and US are related, but how they are related.     

Attentional prioritisation of threatening information: Examining the role of the size of the attentional window

In line with most models of emotion, research has shown that threatening information receives attentional priority over neutral information. Recently, it has been suggested that the degree to which participants divide their attention across the visual field (the attentional window) may modulate the extent to which salient objects are attentionally prioritised. In the current study, participants were required to identify a target inside one of a variable number of coloured circles. One colour (Conditioned Stimulus, CS +) was fear-conditioned using an electrocutaneous stimulus at tolerance level. This search task was combined with a go/no-go task that required participants to either divide attention across the visual field to create a broad attentional window (global group), or focus their attention on the fixation point to create a narrow attentional window (local group). The results showed that only in the global group was the CS + colour prioritised over the neutral colours, indicating that a broader attentional window leads to enhanced attentional prioritisation of threat. Implications for research on attentional bias to threat are discussed.