Emergence of Third-Order Conditional Discriminations from Learning Discriminations with Unrelated Stimuli

This study explored learning and generalization of a third-order conditional discrimination. Two 8-year-old children learned two auditory–visual conditional discriminations in which they selected visual Japanese syllabic symbols in response to syllables spoken by the experimenter. Then, they learned a third-order conditional discrimination in which they selected between two visual symbols after being exposed to two spoken syllables and one visual symbol. Thereafter, we probed generalization with novel symbols and names by teaching two additional conditional discriminations with Nahuatl symbols and spoken words and probing without reinforcement a new third-order conditional discrimination in which they had to select between two visual Nahuatl symbols after being exposed to two spoken Nahuatl words and one visual Nahuatl symbol. The two children responded in a predicted way to the novel third-order conditional discrimination. The emergent performance was possible because the set of relations established among the stimuli of the third-order conditional discrimination with Japanese syllables was analogous to the set of relations established among the stimuli of the third-order conditional discriminations with Nahuatl words. These results demonstrated a novel type of emergent responding in third-order conditional discrimination with arbitrary relations.

Optogenetic suppression of the medial septum impairs working memory maintenance

Spatial working memory (SWM) is the ability to encode, maintain, and retrieve spatial information over a temporal gap, and relies on a network of structures including the medial septum (MS), which provides critical input to the hippocampus. Although the role of the MS in SWM is well-established, up until recently, we have been unable to use temporally precise circuit manipulation techniques to examine the specific role of the MS in SWM, particularly to distinguish between encoding, maintenance, and retrieval. Here, we test the hypothesis that the MS supports the maintenance of spatial information over a temporal gap using precisely timed optogenetic suppression delivered during specific portions of three different tasks, two of which rely on SWM and one that does not. In experiment 1, we found that MS optogenetic suppression impaired choice accuracy of a SWM dependent conditional discrimination task. Moreover, this deficit was only observed when MS suppression was delivered during the cue-sampling, but not the cue-retrieval, portion of the trial. There was also no deficit when MS neurons were optogenetically suppressed as rats performed a SWM-independent variant of the task. In experiment 2, we tested whether MS suppression affected choice accuracy on a delayed nonmatch to position (DNMP) task when suppression was limited to the sample, delay, and choice phases of the task. We found that MS suppression delivery during the delay phase of the DNMP task, but not during the sample or choice phases, impaired choice accuracy. Our results collectively suggest that the MS plays an important role in SWM by maintaining task-relevant information over a temporal delay.

Emergent categorization in the recognition of black and white paintings through conditional discrimination

Background The emergent categorization involving paintings by renowned painters and their corresponding names was demonstrated by previous studies. However, the results of these studies suggest that the colors of the pictures may have played a preponderant role, obscuring other aspects of the stimuli that could be more directly related to the style of each painter. To verify this possibility, the present study used the same methodology of Ferreira et al. to investigate the establishment of emergent conditional relations between categories composed of black and white paintings and the names of their authors. Method The procedure consisted of the training of relations between each of the ten paintings and an abstract picture, for each of the three painters Botticelli, Monet, and Picasso. Relations between each of the three abstract figures and the printed name of one of the painters were verified in sequence. Finally, tests of relations between five trained and five untrained paintings of each artist and the printed names were conducted. Results The participants’ performance suggests that the outcome was properly controlled by aspects pertinent to the paintings that belonged to each painter’s category. Conclusions The results reinforced the data obtained previously with colored pictures, suggesting that the process of emergent categorization involving artificial categories of paintings is robust. It also indicates possibilities for future investigations, for example, using stimuli of other artistic productions, such as sculpture and music.

Conditional Learning Deficits in Children with ADHD can be Reduced Through Reward Optimization and Response-Specific Reinforcement

When children with ADHD are presented with behavioral choices, they struggle more than Typically Developing [TD] children to take into account contextual information necessary for making adaptive choices. The challenge presented by this type of behavioral decision making can be operationalized as a Conditional Discrimination Learning [CDL] task. We previously showed that CDL is impaired in children with ADHD. The present study explores whether this impairment can be remediated by increasing reward for correct responding or by reinforcing correct conditional choice behavior with situationally specific outcomes (Differential Outcomes). An arbitrary Delayed Matching-To-Sample [aDMTS] procedure was used, in which children had to learn to select the correct response given the sample stimulus presented (CDL). We compared children with ADHD (N = 45) and TD children (N = 49) on a baseline aDMTS task and sequentially adapted the aDMTS task so that correct choice behavior was rewarded with a more potent reinforcer (reward manipulation) or with sample-specific (and hence response-specific) reinforcers (Differential Outcomes manipulation). At baseline, children with ADHD performed significantly worse than TD children. Both manipulations (reward optimization and Differential Outcomes) improved performance in the ADHD group, resulting in a similar level of performance to the TD group. Increasing the reward value or the response-specificity of reinforcement enhances Conditional Discrimination Learning in children with ADHD. These behavioral techniques may be effective in promoting the learning of adaptive behavioral choices in children with ADHD.

Naming of Stimuli in Equivalence Class Formation in Children

In the present study, two typically developing 4-year-old children, Pete and Joe, were trained six conditional discriminations and tested for the formation of three 3-member equivalence classes. Pete and Joe did not establish the AC relation within 600 trials and were given two conditions of preliminary training, including naming of stimuli with two different stimulus sets. Pete started with preliminary training with common naming of stimuli, followed by conditional-discrimination training and testing for emergent relations, and continued with preliminary training on individual naming of stimuli, followed by the same training and testing as described previously. Joe experienced the same conditions but in reversed order. Pete responded in accordance with equivalence in the second round in the condition with common naming. In the first round of testing in the condition with individual naming, he responded in accordance with equivalence. In the condition with individual naming, Joe did not respond in accordance with stimulus equivalence but established all of the directly trained relations during training. In the condition with common naming, he responded in accordance with equivalence in the first round of testing. The results from the experiment support earlier findings that both common and individual naming could facilitate the emergence of equivalence classes.

Bigfin reef squid demonstrate capacity for conditional discrimination and projected future carbon dioxide levels have no effect on learning capabilities

Anthropogenic carbon dioxide (CO2) emissions are being absorbed by the oceans, a process known as ocean acidification, and risks adversely affecting a variety of behaviours in a range of marine species, including inhibited learning in some fishes. However, the effects of elevated CO2 on learning in advanced invertebrates such as cephalopods are unknown. Any impacts to the learning abilities of cephalopods could have far-reaching consequences for their populations and the communities they inhabit. Cephalopods have some of the most advanced cognitive abilities among invertebrates and are one of the few invertebrate taxa in which conditional discrimination has been demonstrated, though the trait has not been demonstrated in any species of squid. Here, we tested for the first time the capacity for conditional discrimination in a squid species (Sepioteuthis lessoniana). Furthermore, we investigated the effects of projected future CO2 levels (1,084 µatm) on conditional discrimination and learning more generally. A three-task experiment within a two-choice arena was used to test learning and conditional discrimination. Learning was measured by improvements in task completion in repeated trials over time and the number of trials required to pass each task. Squid exhibited significant learning capabilities, with an increase in correct choices over successive trials and a decrease in the number of trials needed to complete the successive tasks. Six of the 12 squid tested successfully passed all three tasks indicating a capacity for conditional discrimination in the species. Elevated CO2 had no effect on learning or on the capacity for conditional discrimination in squid. This study highlights the remarkable cognitive abilities of S. lessoniana, demonstrated by their capacity for conditional discrimination, and suggests that ocean acidification will not compromise learning abilities. However, other behavioural traits in the species have been shown to be altered at comparable elevated CO2 conditions. It is not clear why some ecologically important behaviours are altered by elevated CO2 whereas others are unaffected. Future research should focus on the physiological mechanism responsible for altered behaviours in squid at elevated CO2.

Children Only 3 Years Can Succeed At Conditional "If, Then" Reasoning, Much Earlier Than Anyone Had Thought Possible

We report results showing success at 3 years on conditional discrimination (CD) -- 12-18 months younger than previously reported. Three-year-olds succeeded when color was a property of the stimulus, rather than a property of the background, as in all past CD testing. Previously, we and others found children succeed on the dimensional change card sort (DCCS) test at 3 years -- 12-24 months earlier than previously reported -- by making color a property of the background, instead of a property of the stimulus, as in standard DCCS testing. Neither the change to CD or DCCS affected the rule structure or reasoning requirements of the task. This double dissociation, with 3-year-olds performing better on CD when color and shape were integrated but better on DCCS when color and shape were separated, indicates that when superficial stimulus properties are modified 3-year-olds can do conditional reasoning and grasp a hierarchical rule structure - but they seem to need perceptual boot-strapping to do that. Children of 3 years evidently have difficulty mentally separating physical dimensions (e.g., color and shape) of the same object and difficulty mentally integrating physical dimensions not part of the same object. These results provide the strongest evidence to date against conceptual accounts of why children of 3 years fail conditional discrimination or card sorting.

Using Stimulus-Equivalence Technology to Teach Skills About Nutritional Content

Twenty-two adult participants, assigned to three conditions, were trained nutrition knowledge (i.e., carbohydrate values) for different food items. In a stimulus sorting test, the participants were asked to sort stimuli (names of food items) into one of three different ranges of carbohydrate values ("less than 20", "20–40", "more than 40" gram per 100 gram). Conditional-discrimination training and testing followed the sorting test, and finally, a postclass formation sorting test of the stimuli used in the conditional-discrimination training. The conditional-discrimination training used tailored stimuli, that is, the food items that each of the participants categorized incorrectly in the sorting test. Participants exposed to Conditions 1 and 2 were trained on six conditional discriminations and tested for the formation of three 3-member classes. Conditions 2 and 3 had a “don’t know” option together with the three different ranges of carbohydrate values in the sorting for tailoring the stimuli. Participants exposed to Condition 3 trained were trained on 12 conditional discriminations and tested for the formation of three 5-member classes. The main findings showed that all but one of the participants responded correctly on at least one test for equivalence class formation and sorted the stimuli correctly in the postclass formation sorting test.