Journal of Experimental Psychology: Animal Behavior Processes

Inaugural editorial for Journal of Experimental Psychology: Animal Behavior Processes.
When applying for the editorship of the Journal of Experimental Psychology: Animal Behavior Processes, I was asked for my “vision” for the Journal, which I have outlined here as an inaugural editorial. My vision is in essence conservative in that I shall take the core of my brief to be that of maintaining the conception of the Journal established by Allan Wagner over 30 years ago and maintained so admirably by the subsequent editors over the intervening decades. I see this conception as having two main components, the first relating to content and the second to procedures. As far as the content is concerned, the primary aim of the Journal is to publish reports of empirical research that use behavior to investigate the psychological processes mediating learning, memory, motivation, and other forms of cognition in animals as diverse as invertebrates and humans. The criterion for publication is that the experimental research addresses issues of significant theoretical import. Although I shall retain the option of publishing Brief Communications, I intend to maintain a very high criterion for these communications. The primary goal will remain that of publishing substantial reports of integrative research that produce closure on an issue or analysis rather than piecemeal work. As far as procedures are concerned, over the last three decades the Journal’s editorial and refereeing process has made an important contribution to the intellectual climate of the research area. I hope to maintain this tradition by resisting pressures to constrain and truncate the refereeing and editorial processes in service of reducing the feedback and publication lags. The Journal publishes papers that have a substantial and sustained impact and therefore can tolerate a reflective and thoughtful editorial process. It is these two features that have enabled the Journal to maintain its position as the premier archival journal in the field, and I take my prime duty to be that of maintaining this preeminent status. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Same–different discrimination: The keel and backbone of thought and reasoning.
Discriminating same from different collections of items is central to human thought and reasoning. Recent comparative research suggests that same–different discrimination behavior is not uniquely human, does not require human language, is based on the variability of the collection of items, obeys fundamental psychophysical laws, and may be captured by quantitative models of the stimulus collection. The comparative study of same–different discrimination behavior sheds fresh light on the mechanisms and functions of abstract conceptualization. This study also has prompted the development of a theory—the Finding Differences Model—that successfully explains a wealth of findings in the comparative psychology of same–different discrimination behavior. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
“Learned predictiveness effects in humans: A function of learning, performance, or both?”: Correction.
Reports an error in "Learned predictiveness effects in humans: A function of learning, performance, or both" by M. E. Le Pelley, M. B. Suret and T. Beesley (Journal of Experimental Psychology: Animal Behavior Processes, 2009[Jul], Vol 35[3], 312-327). In the article “Learned predictiveness effects in humans: A function of learning, performance, or both?” by M. E. Le Pelley, M. B. Suret, and T. Beesley (Journal of Experimental Psychology: Animal Behavior Processes, 35, 312–327), an incorrect equation was printed. The correct version of Equation 2 is: ?ap > 0 if |? - Vp| |? - VQ|. (The following abstract of the original article appeared in record 2009-10283-002.) Many previous studies of animal and human learning indicate a processing advantage for cues previously experienced as good predictors of outcomes over those experienced as poorer predictors. Four studies of human associative learning investigated whether learned predictiveness acts at the level of learning (modulating the rate at which cue–outcome associations form), performance (modulating the strength of behavioral responses), or both. In Experiments 1–3, it was found that retrospectively altering the learned predictiveness of cues influenced responding to those cues, demonstrating that learned predictiveness influences performance. Experiment 4 indicates that learned predictiveness also influences learning by demonstrating that the learned predictiveness of a cue affects the acquisition of an association between a novel cue and the outcome with which it is paired. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Conditional same-different discrimination by pigeons: Acquisition and generalization to novel and few-item displays.
The authors explored whether pigeons can learn to discriminate simultaneously presented arrays of 16 identical (Same) visual items from arrays of 16 nonidentical (Different) visual items, when the correct choice was conditional on the presence of another cue: the color of the background. In one experiment, pigeons rapidly learned this task and, after training with arrays created from a 72-icon set, they exhibited nearly perfect transfer to novel testing arrays. In a second experiment, pigeons’ accuracy to 24-, 20-, 12-, and 8-icon arrays during later testing remained as high as accuracy to training arrays; although accuracy declined with 4- and 2-icon arrays, it was still significantly above chance. In both experiments, pigeons’ choice reaction time scores nicely complemented their choice accuracy scores. These results suggest that the conditional discrimination procedure is well suited to disclose same-different discrimination in pigeons and to elucidate the interaction between perception and abstraction in conceptual learning. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Stages of category learning in monkeys (Macaca mulatta) and humans (Homo sapiens).
Smith and Minda (1998) and Blair and Homa (2001) studied the time course of category learning in humans. They distinguished an early, abstraction-based stage of category learning from a later stage that incorporated a capacity for categorizing exceptional category members. The present authors asked whether similar processing stages characterize the category learning of nonhuman primates. Humans (Homo sapiens) and monkeys (Macaca mulatta) participated in category-learning tasks that extended Blair and Homa’s paradigm comparatively. Early in learning, both species improved on typical items more than on exception items, indicating an initial mastery of the categories’ general structure. Later in learning, both species selectively improved their exception-item performance, indicating exception-item resolution or exemplar memorization. An initial stage of abstraction-based category learning may characterize categorization across a substantial range of the order Primates. This default strategy may have an adaptive resonance with the family resemblance organization of many natural-kind categories. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Implicit and explicit category learning by macaques (Macaca mulatta) and humans (Homo sapiens).
An influential theoretical perspective differentiates in humans an explicit, rule-based system of category learning from an implicit system that slowly associates different regions of perceptual space with different response outputs. This perspective was extended for the 1st time to the category learning of nonhuman primates. Humans (Homo sapiens) and macaques (Macaca mulatta) learned categories composed of sine-wave gratings that varied across trials in bar width and bar orientation. The categories had either a single-dimensional, rule-based solution or a two-dimensional, information-integration solution. Humans strongly dimensionalized the stimuli and learned the rule-based task far more quickly. Six macaques showed the same performance advantage in the rule-based task. In humans, rule-based category learning is linked to explicit cognition, consciousness, and declarative reports about the contents of cognition. These results demonstrate an empirical continuity between human and nonhuman primate cognition, suggesting that nonhuman primates may have some structural components of humans’ capacity for explicit cognition. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
What do Arabic numerals mean to macaques (Macaca mulatta)?
In the past, rhesus macaques (Macaca mulatta) have demonstrated an ability to use Arabic numerals to facilitate performance in a variety of tasks. However, it remained unclear whether they understood the absolute and relative values of numerals. In Experiment 1, numeral-trained macaques picked the larger stimuli when presented with pairwise comparisons involving numerals and analog quantities. In Experiment 2, macaques were provided with numeral cues indicating the number of times a behavior could be performed in one location for a reward. Of the 4 monkeys, 3 performed above chance, but they often erred by performing more behaviors than indicated. The results of these studies indicate that the monkeys have knowledge of the approximate quantities represented by each numeral. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Effect of reward probability on spatial and temporal variation.
Gharib, Derby, and Roberts (2001) proposed that reducing reward expectation increases variation of response form. We tested this rule in a new situation and asked if it also applied to variation of response location and timing. In 2 discrete-trial experiments, pigeons pecked colored circles for food. The circles were of 6 possible colors, each associated with a different probability of reward. Reducing reward expectation did not affect peck duration (a measure of form) but did increase horizontal variation of peck location and interpeck-interval variation. The effect of reward probability on the standard deviation of interpeck intervals was clearer (larger t value) than its effect on mean interpeck interval. Two datasets from rats had similar interresponse-interval effects. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Searching in the middle—Capuchins’ (Cebus apella) and bonobos’ (Pan paniscus) behavior during a spatial search task.
In this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. Five bonobos (Pan paniscus) and 2 capuchin monkeys (Cebus apella) were tested in a series of experiments with the expansion test paradigm. The primates were trained to search in the middle of a 4- or 2-landmark configuration, and were then tested with the same configuration expanded. Neither species searched in the middle of the expanded 4-landmark configuration. When presented with a 2-landmark configuration and a constant or variable inter-landmark training distance, the subjects sometimes searched preferentially in the middle of the expanded configuration. We discuss 2 alternative explanations of the results: extracting a middle rule or averaging between different goal-landmark vectors. In any case, compared to adult humans, primates appear highly constrained in their abilities to search in the middle of a configuration of detached landmarks. We discuss some of the factors that may influence the primates’ behavior in this task. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Rats’ orientation is more important than start point location for successful place learning.
Rats were trained to locate food on a plus maze that was moved between 2 locations. The food was in a fixed location relative to room cues but the maze, and the animals’ start point, were either translated (shifted to the left or right) or rotated (by 90° or 45°) across trials. Rats started from the same or different places solved the problem if they headed in a direction different from the start point. Rats started from different places were impaired if they headed in the same direction, suggesting that orientation is more important than start point for successful performance. The same pattern of results was obtained when rats were trained inside a curtained enclosure, suggesting that orientation is not derived solely from a view of distal visual cues while on the maze. It appears that rats use their heading, or direction of movement, to guide their responses at a choice point. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Learned avoidance of flavors signaling reduction in a nutrient.
Food-deprived rats learned to avoid a flavor negatively correlated with access to a rich nutrient, 20% maltodextrin (20M) solution. This avoidance in two-bottle choice tests was produced by training consisting of either an unpaired condition where sessions of unflavored 20M were intermixed with sessions of 2 or 3% maltodextrin (2M or 3M) flavored with salt (Experiment 1) or almond (Experiments 3 and 4) or a differential conditioning procedure where one flavor was mixed with 20M and another with 2M (Experiment 2). Avoidance was counter-conditioned by mixing the target flavor with 20M (Experiment 1), generalized to a neutral context (Experiment 3), and displayed strong resistance to extinction (Experiment 4). The results demonstrated that food avoidance learning can occur in the absence of an aversive unconditioned stimulus and indicated that unpaired control groups and differential conditioning procedures may be misleading in flavor preference learning research when further control conditions are absent. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Using context to resolve temporal ambiguity.
Three conditioned lick suppression experiments with rats examined the role of the context in the selection and integration of independently acquired interval relationships. In Experiment 1, rats were exposed to separate conditioned stimuli 1 and 2 (CS1–CS2) pairings with 2 different interval relationships, each in its own distinctive context, X or Y. The resultant integration was determined by the training context (X or Y) in which unconditioned stimulus (US)–CS2 backward pairings occurred, as assessed in a third neutral context (Z). In Experiment 2, rats experienced CS1–CS2 pairings with 2 different interval relationships as in Experiment 1, and then received US–CS2 pairings in both contexts X and Y. The testing context (i.e., X or Y) determined the resultant integration. In Experiment 3, rats were exposed to CS1–CS2 pairings in 2 different interval relationships each in different phases (i.e., Phases 1 and 2), and then in Phase 3 received US–CS2 pairings. The temporal context of testing (i.e., short or long retention interval) determined the resultant integration. Thus, both physical and temporal context can be used to disambiguate conflicting temporal information. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Contrasting predictions of extended comparator hypothesis and acquisition-focused models of learning concerning retrospective revaluation.
Three conditioned suppression experiments with rats investigated contrasting predictions made by the extended comparator hypothesis and acquisition-focused models of learning, specifically, modified SOP and the revised Rescorla–Wagner model, concerning retrospective revaluation. Two target cues (X and Y) were partially reinforced using a stimulus relative validity design (i.e., AX–Outcome; BX–No outcome; CY–Outcome; DY–No outcome), and subsequently one of the companion cues for each target was extinguished in compound (BC–No outcome). In Experiment 1, which used spaced trials for relative validity training, greater suppression was observed to target cue Y for which the excitatory companion cue had been extinguished in relation to target cue X for which the nonexcitatory companion cue had been extinguished. Experiment 2 replicated these results in a sensory preconditioning preparation. Experiment 3 massed the trials during relative validity training, and the opposite pattern of data was observed. The results are consistent with the predictions of the extended comparator hypothesis. Furthermore, this set of experiments is unique in being able to differentiate between these models without invoking higher-order comparator processes. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Contrasting the edge- and surface-based theories of object recognition: Behavioral evidence from macaques (Macaca mulatta).
This study assessed the contribution of edge and surface cues on object representation in macaques (Macaca mulatta). In Experiments 1 and 2, 5 macaques were trained to discriminate 4 simple volumetric objects (geons) and were subsequently tested for their ability to recognize line drawings, silhouettes, and light changes of these geons. Performance was above chance in all test conditions and was similarly high for the line drawings and silhouettes of geons, suggesting the use of the outline shape to recognize the original objects. In addition, transfer for the geons seen under new lighting was greater than for the other stimuli, stressing the importance of the shading information. Experiment 3, using geons filled with new textures, showed that a radical change in the surface cues does not prevent object recognition. It is concluded that these findings support a surface-based theory of object recognition in macaques, although it does not exclude the contribution of edge cues, especially when surface details are not available. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Contrasting object-based and texture-based accounts of same/different discrimination learning with trial-unique stimuli.
Same/different discrimination is a classic task for investigating relational learning in animals. Recent research suggests that pigeons can learn a trial-unique same/different discrimination, which eliminates the opportunity to memorize the training items (Brooks & Wasserman, 2008). The authors conducted three tests to elucidate the role that item-based comparison plays in this trial-unique discrimination. In the first, the authors tested the possibility that pigeons’ same/different discrimination was based on textural features of the displays by creating a single, unitary texture from same and different displays; pigeons failed to discriminate these unitary textural displays. In the second, the authors varied the number of items (mosaics) in the display and the authors reproduced the characteristic decline in performance associated with fewer items. In the third, the authors systematically increased the area of two mosaics to closely match the area occupied by increasing numbers of mosaics; the results obtained with two small items persisted even when the size of the mosaics was increased. These results clearly show that pigeons’ same/different discrimination was based on object-level variability and not on other properties of the displays. (PsycINFO Database Record (c) 2009 APA, all rights reserved)

Journal of Experimental Psychology: Animal Behavior Processes - Vol 36, Iss 1