Cue interactions in flavor preference learning: A configural analysis: Correction to Dwyer et al. (2011).

Reports an error in Cue interactions in flavor preference learning: A configural analysis by Dominic M. Dwyer, Mark Haselgrove and Peter M. Jones (Journal of Experimental Psychology: Animal Behavior Processes, 2011[Jan], Vol 37[1], 41-57). There was an error in Figure 3. The X-axis of both panels of this figure should be labeled “3-trial block” and not “trial.” The analysis of the simulations presented in Figure 3 are unaffected by this change. The corrected figure is provided in the erratum. (The following abstract of the original article appeared in record 2011-01268-001.) Four experiments showed that the preference normally established to a neutral flavor cue that was paired with maltodextrin was attenuated when that cue was conditioned in compound with another flavor—overshadowing. Furthermore, two experiments showed that the preference for a neutral flavor conditioned as part of a compound was further attenuated if the other element in that compound was separately paired with the reinforcer—blocking. These results stand in contrast to a number of previous compound flavor preference conditioning experiments, which have not revealed reliable cue competition effects. These discrepant findings are discussed in terms of the effects of within-compound associations and a configural perspective on potentiation. Modeling of this configural perspective predicts that a compound of two separately trained cues will elicit a similar response to the individual cues themselves—absence of summation. Two experiments confirmed this prediction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Configural learning without configural training.

Rats learned discriminations in which 2 familiar compound visual stimuli AB and CD were nonreinforced, whereas less-familiar compounds (EF, GH, IJ…) were reinforced (constant-negative paradigm). Such discriminations can in principle be acquired through elemental (nonconfigural) learning. Three different types of compound—object/object, object/position, and shape/fill-pattern—were used, and the number of familiar compounds extended to 3 or 4. In all cases, when rats were tested for the first time with previously unseen recombinations of the familiar elements—for example, AC, BD—they preferred these to the familiar compounds, implying that they had encoded configural information during the original training. Moreover, preference remained constant despite extended exposure to configural training in the test phase. The findings extend the evidence that configural representations are formed independently of explicit configural training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potentiation, overshadowing, and blocking of spatial learning based on the shape of the environment.

Rats were trained in Experiment 1 to find a submerged platform in 1 corner of either a rectangular or a kite-shaped pool. When the walls creating this corner were a different color than the opposite walls, then learning about the shape of the pool was potentiated in the kite but not in the rectangle. Experiments 2-4 revealed that learning about the rectangle can be overshadowed and blocked when information about the wall color indicates the location of the platform. The results mimic findings that have been obtained with Pavlovian conditioning, and they challenge the claim that learning about the shape of the environment takes places in a dedicated geometric module. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction of conditioned flavor preferences.

In a series of 4 experiments, the effects of extinction on flavor preferences conditioned by mixing flavor cues with a nutrient were examined. In each experiment it was observed that rats preferred a flavor cue that had not undergone extinction to one that had. In addition, this preference was reversed in subjects trained thirsty (Experiments 1 and 2) if the associated nutrient had been devalued prior to the test or the preference for the nonextinguished cue was attenuated by nutrient devaluation in subjects trained hungry (Experiments 3 and 4). The results suggest that extinction may weaken associations between the flavor and the specific sensory properties of the nutrient and, for subjects trained hungry, between the flavor and the motivational components of the nutrient as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing elemental and configural associative theories in human causal learning: A case for attention.

In two causal learning experiments with human participants, the authors compared various associative theories that assumed either elemental (unique cue, modified unique cue, replaced elements model, and Harris' model) or configural processing of stimuli (Pearce's theory and a modification of it). The authors used modified patterning problems initially suggested by Redhead and Pearce (1995). Predictions for all theories were generated by computer simulations. Both configural theories and the unique cue approach failed to account for the observations. The replaced elements model was able to account for part of the data, but only if the replacement parameters could vary across discrimination problems. The Harris model and the modified unique cue approach, assuming that the salience of stimuli decreases with an increasing number of stimuli in a compound, successfully accounted for all of our data. This success implies that attentional factors should be explicitly taken into account in associative learning theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reinforcer devaluation in palatability-based learned flavor preferences.

Rats exposed to simultaneous compounds of 1 neutral flavor with dilute (2%) sucrose and a 2nd flavor with dilute (2%) maltodextrin subsequently consumed both flavors in preference to a 3rd flavor that was never paired with a palatable taste. Brief training exposure under ad lib food and water minimized the postingestive effects of nutrients, emphasizing the contribution of palatability to these preferences. Devaluation of sucrose or maltodextrin by pairing with illness (Experiment 1) or sensory-specific satiety (Experiment 2) selectively reduced the preference for the flavor previously paired with the devalued reinforcer. Such reinforcer-specific devaluation effects suggest that palatability-based learned flavor preferences are underpinned by a Pavlovian process whereby the cue flavor is associated with the taste of the concurrently consumed palatable reinforcer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancement of responding to A after A+/AX+ training: Challenges for a comparator theory of learning.

Two appetitive Pavlovian conditioning experiments with rats investigated the associative changes that A undergoes in an A+/AX+ blocking procedure. Conditioned responding to A was enhanced relative to stimulus B, which had been conditioned in isolation (B+). This result was interpreted in terms of the formation of a within-compound association between A and X. The results of Experiment 2 supported this conclusion by demonstrating that X had associative strength of its own and, furthermore, that extinguishing X resulted in a similar level of responding to A and B. These results are considered in terms of retrospective revaluation theories of learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer of configural learning between the components of a preexposed stimulus compound: Implications for elemental and configural models of learning.

In 2 experiments, rats received preexposure to 2 compound contexts: AB and CD for the congruent group and AC and BD for the incongruent group. Subsequently, all rats received a configural discrimination in which separate placement in contexts A or B indicated that presentations of stimulus X would be followed by food and presentations of Y would not, and separate placement in contexts C and D indicated that Y would be followed by food and X would not. In both experiments, rats in the congruent group acquired the conditional discrimination more rapidly than those in the incongruent group. These results are inconsistent with conventional associative accounts of either stimulus preexposure effects or configural learning and instead provide support for a connectionist account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blocking and overshadowing in human geometry learning.

In a two-dimensional computer-based search task, human participants were required to learn the location of a goal by using the geometric information available on the screen. When the goal location was defined by two shapes that differed in salience, the more salient shape overshadowed learning based on the less salient shape but not the other way round. Furthermore, when one shape was pretrained as a signal for the location of the goal, learning about the geometric cues of the other shape was blocked. These results suggest that spatial learning based on geometry is ruled by associative principles and support learning models that do not invoke a special status for geometric cues (e.g., Miller & Shettleworth, 2007). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parabrachial nucleus lesions block taste and attenuate flavor preference and aversion conditioning in rats.

Rats with ibotenic acid lesions of the parabrachial nucleus (PBN) failed to learn a taste aversion induced by lithium chloride (LiCl) toxicosis. The same rats also did not learn to prefer a taste that was paired with intragastric (IG) carbohydrate infusions during 22 hr/day trials. The PBN-lesioned rats did learn to prefer a flavor (odor?+?taste) paired with the IG carbohydrate infusions over a different flavor paired with IG water. The PBN-lesioned rats also learned to avoid a flavor paired with IG LiCl infusions during 22 hr/day trials. The flavor preference and aversion, however, were less pronounced than those displayed by control rats. These data indicate that the PBN is essential for forming orosensory-viscerosensory associations when taste is the primary cue but is less critical when more complex flavor cues are available. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal patterns of variable relationships in person-oriented research: Longitudinal models of configural frequency analysis.

This article reviews the premises of configural frequency analysis (CFA), including methods of choosing significance tests and base models, as well as protecting α, and discusses why CFA is a useful approach when conducting longitudinal person-oriented research. CFA operates at the manifest variable level. Longitudinal CFA seeks to identify those temporal patterns that stand out as more frequent (CFA types) or less frequent (CFA antitypes) than expected with reference to a base model. A base model that has been used frequently in CFA applications, prediction CFA, and a new base model, auto-association CFA, are discussed for analysis of cross-classifications of longitudinal data. The former base model takes the associations among predictors and among criteria into account. The latter takes the auto-associations among repeatedly observed variables into account. Application examples of each are given using data from a longitudinal study of domestic violence. It is demonstrated that CFA results are not redundant with results from log-linear modeling or multinomial regression and that, of these approaches, CFA shows particular utility when conducting person-oriented research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context conditional flavor preferences in the rat based on fructose and maltodextrin reinforcers.

In three experiments, rats were exposed to a flavor preference procedure in which flavor A was paired with the reinforcer and flavor B presented alone in Context 1, while in Context 2 flavor A was presented alone and flavor B with the reinforcer. With fructose as the reinforcer both two- and one-bottle training procedures produced a context-dependent preference (Experiments 1 and 2). With maltodextrin as the reinforcer two-bottle training produced a context-dependent preference (Experiment 1). Following one-bottle training with maltodextrin reinforcement rats demonstrated a context-dependent preference when the conditioned stimulus (CS)- was presented with a dilute solution of the reinforcer during training (Experiment 3B) but not when the CS- was presented alone (Experiments 2 and 3A). The pattern of results with maltodextrin reinforcement suggests that there was competition between the cue flavors and the taste of the maltodextrin as predictors of the postingestive consequences of the maltodextrin reinforcer. The fact that rats were able to display context-dependent flavor preferences is consistent with the idea that learned flavor preferences rely on the sort of cue-consequence associations that underpin other forms of conditioning which produce accurate performance on biconditional tasks. The differences between fructose- and maltodextrin-based preferences are discussed in terms of configural and elemental learning processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence of Preference for a Flavor Presented in Simultaneous Compound With Sucrose.

Rats exposed to a simultaneous compound of a flavor and sucrose subsequently exhibited a preference for the flavor over water. This preference persisted across repeated testing even though the flavor was presented in the absence of sucrose. The preference did, however, extinguish if the rats were hungry when trained or tested, or if they had been reexposed to sucrose between training and test. Though failing to extinguish the preference, presentation of the flavor outside the compound protected it from the effects of sucrose devaluation, indicating that these presentations extinguished the within-compound association between the flavor and sucrose. The authors conclude that the hedonic reaction elicited by sucrose imbues the flavor with the same hedonic properties, and these properties maintain the preference independently of the flavor-sucrose association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of similarity in human associative learning.

In 2 experiments, humans received sequences of patterns that were similar (AX→BX, AY→BY, AZ→BZ) or dissimilar (CX→DY, CY→DZ, CZ→DX). The patterns were portrayed as bugs that could be eliminated with 2 insecticide sprays (red or blue). Either spray eliminated bugs with Features A and C, and participants learned by trial and error to use one spray (e.g., red) to eliminate bugs with Feature B and the other spray (e.g., blue) to eliminate those with Feature D. In Experiment 1, participants' spray choice for bugs with Feature A came to match that used to eliminate bugs with Feature B, but there was no such associative transfer between Features C and D. That is, similarity promoted associative transfer of responding between paired patterns when the features used to manipulate similarity (i.e., X, Y, and Z) were irrelevant. In Experiment 2, in which X, Y, and Z were relevant to the solution of configural discrimination, similarity hindered such associative transfer. These results complement those found in pigeons (R. A. Rescorla & D. J. Gillan, 1980) and indicate that similarity should not be accorded independent status as a principle of associative learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequential and simultaneous feature positive discriminations: Occasion setting and configural learning in human Pavlovian conditioning.

Using a conditioned suppression preparation, the authors investigated sequential (X→A+/A–) versus simultaneous (XA+/A–) feature positive (FP) discrimination learning in humans. The sequential discrimination was expected to be resolved by means of a Feature X Modulated Target A–US association and the simultaneous discrimination by a feature X–US association. After sequential FP training, extinction of Feature X did not affect discriminative X→A/A responding (Experiment 1), and X transferred its modulatory ability only to new targets, B, that had also been modulated (Experiment 2). This suggests that the sequential FP discrimination indeed resulted in occasion setting. Unlike expected, Feature X Extinction did not affect discriminative XA/A responding after simultaneous FP training (Experiment 3), while at the same time Feature X did show the predicted nonselective transfer to new targets, B (Experiment 4). J. M. Pearce's (1987) configural learning theory can account for most but not all findings of Experiments 3 and 4. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of the content of configural representations: The role of associatively evoked and trace memories.

Two experiments examined the content of configural learning in rats. In Experiment 1, after simple pre-exposure to two hybrid contexts (AB and CD), rats acquired a configural discrimination involving two of the contexts (A and C) and two auditory stimuli (X and Y; AX→food, AY→no food, CX→no food, and CY→food). When rats were then placed in context B, they were more likely to respond to X than Y, and when they were placed in context D the reverse was the case. Experiment 2 demonstrated that rats can acquire a configural discrimination involving the presence of context (A) and its memory trace (a; AX→food, AY→no food, aX→no food, and aY→food). These results show that associatively provoked memories (Experiment 1) and memory traces (Experiment 2) can participate in configural discriminations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expression of flavor preference depends on type of test and on recent drinking history.

The persistence of a conditioned flavor preference was examined in 3 experiments. All contained an initial acquisition phase in which half the rats were given almond odor mixed with sucrose (AS) in some sessions and water (W) only in other sessions, whereas the other half (controls) were given explicitly unpaired exposures to almond (A) and sucrose (S) in separate sessions. Subsequent 2-bottle choice tests revealed a persistent preference for A, despite extinction exposure to A or S, but this depended on the choice offered on test: Exposure to A did not extinguish the preference for A over W but did reduce the preference for AS over S; conversely, exposure to S did not extinguish the preference for AS over S but did reduce the preference for A over W. These results indicate that flavor preferences can be resistant to extinction procedures but suggest that the expression of such preferences in choice tests depends on an adaptation-level process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Caffeine-reinforced conditioned flavor preferences in rats.

In 4 experiments, rats were trained to associate 1 of 2 differently flavored solutions with caffeine. During later 2-bottle extinction tests, they consistently preferred flavors that had been previously mixed with 2 lower (0.25 and 0.125 mg/ml), but not 2 higher (0.5 and 0.75 mg/ml), caffeine concentrations. Hunger during conditioning increased the size of these preferences, but neither preexposure to unflavored caffeine nor hunger during the choice test had any effect on them. Because caffeine is noncaloric, this last finding strengthens the hypothesis that hunger enhances the expression of only calorie-based conditioned flavor preferences. More fundamentally, the present results represent the first clear evidence that, through Pavlovian conditioning, rats can develop preferences for flavors associated with caffeine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial learning based on the shape of the environment is influenced by properties of the objects forming the shape.

In 3 experiments rats had to find a submerged platform that was located in a corner of a kite-shaped pool. The color of the walls creating this corner provided an additional cue for finding the platform in the shape + color condition but not the shape-only condition. During tests in a pool with walls of a uniform color but no platform, more time was spent in the corner where the platform was originally located after training in the shape + color than in the shape-only condition. The results challenge theories that assume either that learning about the shape of the environment takes place in a dedicated module or that cues compete for the control they acquire over behavior. (PsycINFO Database Record (c) 2011 APA, all rights reserved)