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This study partially replicated the research of Cook, Kwak, Hoffman, & Loftus where they examined post-event activities that induces subjects to pick a wrong person in a forced choice identification procedure. The goal was to investigate if providing a neither option to a match to sample task increases the accuracy of responding. Subjects were asked to study three faces for 10 seconds, after which they were asked to pick out the faces in a forced choice setting where two other faces were presented. Later the subjects were asked to pick out faces in a setting in which they could use a neither option. Results indicated that a generalization effect occurs when identifying faces and the effect is seen as subjects choosing the wrong face. This suggests that when using faces with some similar features in a lineup setting the procedure may cause the subject to pick the wrong person.

While it is known that acute and chronic stress can impact cognition, less is known about the immediate impacts of minor frustrations or positive experiences on subsequent behavior and cognition in primates. This study used a novel methodology to engineer both a positive and (slightly) frustrating experience, using the same apparatus, in 15 adult capuchin monkeys. Subjects were presented with a working memory task (DMTS) for 30 minutes after the experimental manipulations (or a control). As predicted, the frustrating task prior to testing resulted in a decrease in performance on the DMTS compared to performance after a positive experience or the control. Contrary to predictions, a positive experience did not facilitate performance to higher levels than the control condition. Manipulations also impacted several behaviors. Although there may be different results in different contexts, these results indicate that even mild negative experiences impact subsequent behavior and cognition in primates.

The experimenter asked if documented equivalence class membership would influence the development of shared discriminative stimulus function established through simple successive discrimination training. In Experiment 1, equivalence classes were established with two sets of 9 stimuli. Common stimulus functions were then trained within or across the equivalence classes. Greater acquisition rates of the simple discriminations with stimuli drawn from within the equivalence classes were observed. In Experiment 2, a third stimulus set was added with which no equivalence relations were explicitly trained. The findings of Experiment 1 were replicated, but the Set 3 results were inconsistent across subjects. The outcomes of the two experiments demonstrate that equivalence classes have an effect on other behavioral relations which requires further investigation.

The study assessed how stimuli that contradict pre-experimental histories affect the formation of new relations. The study also assessed whether social variables such as race would influence college students’ perceptions of people of different races and job types. Twenty-six college students at a Midwestern University participated in the study. During the pre-test, participants rated the degree of “Good” or “Bad” of various pictures of African American males, police officers, and random objects on a Likert-type scale. Next, based on their pre-test results, participants completed a match to sample task that paired pictures of African American males and police officers opposite of their initial perceptions. Afterward, all participants again completed the Likert-scale rating task. Pre-test results revealed that some participants demonstrated strong negative pre-experimental biases toward police officers and that the race of the participants influenced their pre-test ratings. Individual data showed that 22 out of 24 participants changed their perceptions for at least one stimulus. Match to sample and post-test results revealed that participants with strong pre-experimental biases took more trials to complete the task, scored less accurately when conditions included socially loaded stimuli, and were less likely to change mean ratings for police officers during the post-test rating scale.

If an organism is explicitly taught an A->B association, then might it also spontaneously learn the symmetrical B->A association? There is only a small amount of evidence that attests to the detection of emergent symmetry in nonhuman animals (e.g., one chimpanzee and two pigeons). This report examines the necessary and sufficient conditions for finding emergent symmetry in pigeons while attempting to control for the problems of spatial and temporal location found in previous symmetry and stimulus equivalence experiments. Using a successive go/no go matching-to-sample procedure, which showed all of the training and testing stimuli in one location, four experimental manipulations were examined. In Experiment 1 temporal location was controlled without the inclusion of identity matching intermixed with arbitrary matching; Experiment 2 contained identity matching with stimuli different from arbitrary matching; in Experiment 3 identity matching was trained to criterion and then intermixed with arbitrary matching; and in Experiment 4 two sets of arbitrary matching were trained (e.g., AB and CD) but only one of those stimulus sets was trained in identity matching (e.g., AB). No evidence of emergent symmetry was found in Experiments 1 and 2. In Experiment 3, two pigeons showed moderate evidence of emergent symmetry, one pigeon showed suggestive evidence of emergent symmetry, and one pigeon did not show any evidence of emergent symmetry. In Experiment 4, two pigeons showed moderate evidence of emergent symmetry with the AB Stimulus Set (one of those pigeons also showed suggestive evidence of emergent symmetry with the CD Stimulus Set) and one pigeon did not show any evidence of emergent symmetry with either stimulus set. These data suggest that intermixing identity matching with the same stimuli used in arbitrary matching is a necessary, but not sufficient condition to obtaining emergent symmetry in pigeons.

Functional magnetic resonance imaging (fMRI) is a relatively new tool that has been used to examine patterns of neural activation within those with traumatic brain injuries (TBI). A review of relevant literature is presented, including alterations in activity within the frontal and parietal regions that are thought to be compensatory in nature. In addition, possible explanations for discrepancies within this research are discussed. The current study expands upon previous work by incorporating a delayed-match-to-sample (DMS) task within an event-related paradigm and neuropsychological testing to compare 12 individuals with a history of TBI to 12 control participants with orthopedic injuries (OI). Participants in the TBI group were high functioning and in the chronic stage of recovery. Neuropsychological testing revealed statistically significant group differences in measures of working memory, processing speed, memory, and executive functioning. However, groups were comparable in accuracy on the DMS task. Percent signal changes in fMRI data revealed statistically significantly increased activation within the right dorsolateral prefrontal cortex (BA 46) for the TBI group compared to controls. Additional alterations in activation were found between groups within the inferior temporal (BA 37) and parietal (BA 7) regions. Regression analyses showed no relationship between neuropsychological testing and percent signal change within BA 46, but predictive relationships between testing and BA 37 and BA 7. Logistic regression analyses suggest that fMRI data did not add any incremental predictive value beyond neuropsychological testing alone when attempting to predict group (TBI vs. OI) membership.

Pigeons were trained on a zero-delay identity match-to-sample task. Experiment 1 started with every correct match reinforced with grain access and subsequent conditions include higher fixed-ratio values. Experiment 2 included the same fixed-ratio values as experiment 1 with and without a limited hold (LH) on the opportunity to select a comparison stimulus. Prior research suggested that trials after reinforcement would have an increased likelihood of error, and that these errors would be reduced in LH conditions. Results confirmed this expected error pattern and in most LH conditions errors were reduced early in the ratio.

Twenty-six participants, divided into three groups, learned to relate English words to Czech and Portuguese words in a matching-to-sample procedure. Half the word pairs were learned using English words as samples and foreign words as corresponding comparisons and the other half were learned with the foreign words serving as samples and English words as corresponding comparisons. The only difference in training across the three groups involved a programmed delay between the removal of the sample stimulus and the presentation of comparison stimuli. For Group 0, Group 2, and Group 8, the programmed delay values between sample offset and comparison onset were 0 s, 2 s, and 8 s, respectively. Test trials assessed the extent to which the conditional discriminations established during training had become reversible or the extent to which the effects of learning had transferred to a new situation. The results suggest that the likelihood of transfer was greatest for the group that learned the task with the largest delay (i.e., an 8 s delay between sample offset and comparison onset).

Fluent performance has been described as the retention, endurance, stability, and application of the material learned. Fluent performers not only respond quickly during training, they also make many correct responses during training. The current study used a within-subject design to analyze the effects of increased response rates on Retention, Endurance, Stability, and Application tests. Number of correct responses and number of unprompted, correct responses in error correction procedures were yoked for individual participants across an Accuracy-plus-Rate training condition and an Accuracy-Only training condition. One participant scored better in tests that followed the Accuracy-Only condition. One participant showed results that slightly favor the Accuracy-plus-Rate training condition. The two participants whose response rates were successfully reduced in the Accuracy-Only condition performed better on all tests that followed the Accuracy-plus-Rate condition.