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We report how the trajectories of saccadic eye movements are affected by memory interference acquired during associative learning. Human participants learned to perform saccadic choice responses based on the presentation of arbitrary central cues A, B, AC, BC, AX, BY, X, and Y that were trained to predict the appearance of a peripheral target stimulus at 1 of 3 possible locations, right (R), mid (M), or left (L), in the upper hemifield. We analyzed as measures of associative learning the frequency, latency, and curvature of saccades elicited by the cues and directed at the trained locations in anticipation of the targets. Participants were trained on two concurrent discrimination problems A+R, AC+R, AX+M, X+M and B+L, BC+L, BY+M, Y+M. From a connectionist perspective, cues were predicted to acquire associative links connecting the cues to the trained outcomes in memory. Model simulations based on the learning rule of the Rescorla and Wagner (1972) model revealed that for some cues, the prediction of the correct target location was challenged by the interfering prediction of an incorrect location. We observed that saccades directed at the correct location in anticipation of the target curved away from the location that was predicted by the interfering association. Furthermore, changes in curvature during training corresponded to predicted changes in associative memory. We propose that this curvature was caused by the inhibition of the incorrect prediction, as previously has been suggested with the concept of distractor inhibition (Sheliga, Riggio, & Rizzolatti, 1994; Tipper, Howard, & Houghton, 2000). The paradigm provides a new method to examine memory interference during associative learning. (Contains 1 footnote, 2 tables, and 10 figures.)

In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y-) was trained in Context A. During Phase 2, participants received discrimination reversal training (X-, Y+) either in Context A (Group AAB) or in Context B (Group ABA, Group ABC). Testing occurred in the reversal context and in a neutral context (Group AAB, Group ABC) or in the reversal context and in the acquisition context (Group ABA). Recovery effects were similar in ABA and ABC procedures, whereas no AAB recovery effect occurred. Furthermore, the rate of discrimination reversal learning during Phase 2 was unaffected by whether training was conducted in the same or in a different context as initial learning. Results indicate that contextual stimuli are processed before interfering information is presented. These representations, however, do not acquire the ability to control performance. (Contains 2 figures and 1 table.)

In two conditioning experiments with humans, we found that participants' prior experience exerted considerable influence on later learning of configural discrimination problems. Prior experience was manipulated by pre-training participants before the main acquisition stage. They either received a discrimination problem that encouraged an elemental solution (A+, B-, AB+, CD- in Experiment 1 and A+, AB+, C-, CB- in Experiment 2) or one that required a configural solution (AB+, BC-, CD+, DA- in Experiment 1 and A-, AB+, C+, CB- in Experiment 2). Then, all participants were shown a discrimination that required a configural solution (E+, F+, EF- in Experiment 1 and DE+, EF-, FG+, GD- in Experiment 2). In both experiments, participants who had received elemental pre-training were impaired on the later configural problem compared to participants who had received configural pre-training. The results suggest that organisms can flexibly process stimuli elementally or configurally.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.lmot.2007.08.001 Byline: Metin Angor, Harald Lachnit Keywords: Human predictive learning; Discrimination reversal; Context change; Renewal; Reinforcement history Abstract: In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y-) was trained in Context A. During Phase 2, participants received discrimination reversal training (X-, Y+) either in Context A (Group AAB) or in Context B (Group ABA, Group ABC). Testing occurred in the reversal context and in a neutral context (Group AAB, Group ABC) or in the reversal context and in the acquisition context (Group ABA). Recovery effects were similar in ABA and ABC procedures, whereas no AAB recovery effect occurred. Furthermore, the rate of discrimination reversal learning during Phase 2 was unaffected by whether training was conducted in the same or in a different context as initial learning. Results indicate that contextual stimuli are processed before interfering information is presented. These representations, however, do not acquire the ability to control performance. Author Affiliation: Faculty of Psychology, Philipps-Universitat Marburg, GutenbergstraAe 18, 35032 Marburg, Germany Article History: Received 20 April 2007; Revised 8 August 2007 Article Note: (footnote) [star] This research is part of the doctoral thesis of Metin Angor and was supported by the DFG graduate program 'Brain and Behavior' (DFG 885/1). We thank Andreas Malkmus, Anna Lilienfeld, Jana Becht, Jeannine Kolender, Johannes Lange, Michele Wrede, and Pit Marquardt for their help with data collection.

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. Keywords: associative learning, Pavlovian conditioning, elemental, configural, discrimination

In 3 human predictive learning experiments, the authors examined contextual control of responding in discrimination reversal learning. In Phase 1, a discrimination between 2 stimuli (A+, B-) was trained in Context 1. During Phase 2, participants received discrimination reversal training (A-, B +) in Context 2. Testing occurred in Context 1 and Context 2 (Experiments 1A and 1B) or in Context 1 and Context 3 (Experiment 2). During the test phase, performance in Context 1 and Context 2 reflected the contingencies trained during Phase 1 and Phase 2, respectively. When testing occurred in Context 3, there was no discriminative responding between A and B. In addition, the experiments demonstrated that discriminating stimuli with a consistent reinforcement history were also affected by contextual manipulations. Results indicate that each training context acquires the ability to control performance. Unique-cue and configural approaches account for a major part of the results. Keywords: human predictive learning, discrimination reversal, context change, renewal, reinforcement history

Participants were shown A+ and C- trials followed by AB+ and CD+ trials. These trials were embedded in a causal learning task in which participants had to learn either the relationship between different foods and allergic reactions or the relationship between different stocks and an increase in the stock market index. The authors orthogonally varied the manner in which the different cues were presented to participants during training. Cue competition was related to the causal learning scenario but not to the manner in which the different cues were presented. These results question claims of a human bias toward configural processing that were based on difficulties in finding cue competition in some previous causal learning experiments. Keywords: human causal learning, experimental task, elemental, configural, cue competition

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.lmot.2004.06.002 Byline: Klaus G. Melchers (a)(b), Harald Lachnit (b), Metin Angor (b), David R. Shanks (c) Keywords: Elemental processing; Configural processing; Pavlovian conditioning; Associative learning; Transfer of learning; Skin conductance response; Humans Abstract: In two conditioning experiments with humans, we found that participants' prior experience exerted considerable influence on later learning of configural discrimination problems. Prior experience was manipulated by pre-training participants before the main acquisition stage. They either received a discrimination problem that encouraged an elemental solution (A+, B-, AB+, CD- in Experiment 1 and A+, AB+, C-, CB- in Experiment 2) or one that required a configural solution (AB+, BC-, CD+, DA- in Experiment 1 and A-, AB+, C+, CB- in Experiment 2). Then, all participants were shown a discrimination that required a configural solution (E+, F+, EF- in Experiment 1 and DE+, EF-, FG+, GD- in Experiment 2). In both experiments, participants who had received elemental pre-training were impaired on the later configural problem compared to participants who had received configural pre-training. The results suggest that organisms can flexibly process stimuli elementally or configurally. Author Affiliation: (a) Psychologisches Institut, Universitat Zurich, Ramistrasse 62, CH-8001 Zurich, Switzerland (b) Philipps-Universitat Marburg, Germany (c) University College London, UK Article History: Received 3 February 2004; Revised 24 June 2004 Article Note: (footnote) [star] The research reported in this article was supported by Grants La 564/12-1 and La 564/12-3 from the German Science Foundation (Deutsche Forschungsgemeinschaft) to Harald Lachnit. We thank Sarah Schreckenberg, Kathrin Hansen, and Nina Hartwich for their help with the experiments. K. G. Melchers has previously published with the surname 'Lober.'

In three human causal learning experiments we investigated the role of within-compound associations in learning about absent cues versus learning about present cues. Different theoretical approaches agree that within-compound associations are essential for learning about absent cues--that is, for retrospective revaluation. They differ, however, with regard to the role of within-compound associations for learning about present cues--that is, for direct learning. A memory test was used to assess within-compound associations. Experiment 1 used a blocking/release from overshadowing design, Experiment 2 used a conditioned inhibition design, and Experiment 3 used a higher-order cue selection design. In all experiments, first-order retrospective revaluation was significantly correlated with within-compound associations, but no significant correlations were found for the direct learning conditions. In addition to this, second-order retrospective revaluation in Experiment 3 was positively correlated to joint knowledge of first-order and second-order within-compound associations. Furthermore, cue selection effects were stronger for direct learning conditions than for retrospective learning conditions. These results are at variance with the comparator hypothesis but are in agreement with a modified associative theory and with the suggestion that retrospective revaluation might be due to rehearsal processes.

Two experiments are reported, which employed a Pavlovian eyelid conditioning procedure with human participants. The experiments tested the predictions of three models of the time-course of processing under time pressure. These were the extended generalized context model (Lamberts, 1998), and two variants of the Rescorla-Wagner model (Rescorla & Wagner, 1972), which were activated in cascade mode. Reinforcement schedules in the experiments were equivalent either to an AND rule or to an XOR rule. The time available for processing the conditioned stimulus and initiating a conditioned response was manipulated by varying the interval from the onset of the conditioned stimulus to the onset of the unconditioned stimulus. The results were in accord with the predictions of one of the two variants of the Rescorla-Wagner model.