Comparing the effects of echoic prompts and echoic prompts plus modeled prompts on intraverbal behavior

We compared strategies to teach vocal intraverbal responses to an adolescent diagnosed with autism and Down syndrome. One strategy involved echoic prompts only. The second strategy involved an echoic prompt paired with a modeled prompt in the form of sign language. Presenting the modeled prompt with the echoic prompt resulted in faster acquisition of correct responding. Results are discussed in terms of using functional stimulus classes to facilitate vocal intraverbal acquisition with learners who have a history of sign language training.     

Children's reasoning about spatial relational similarity: the effect of alignment and relational complexity

We investigated 4- and 5-year-old children's mapping strategies in a spatial task. Children were required to find a picture in an array of three identical cups after observing another picture being hidden in another array of three cups. The arrays were either aligned one behind the other in two rows or placed side by side forming one line. Moreover, children were rewarded for two different mapping strategies. Half of the children needed to choose a cup that held the same relative position as the rewarded cup in the other array; they needed to map left-left, middle-middle, and right-right cups together (aligned mapping), which required encoding and mapping of two relations (e.g., the cup left of the middle cup and left of the right cup). The other half needed to map together the cups that held the same relation to the table's spatial features-the cups at the edges, the middle cups, and the cups in the middle of the table (landmark mapping)-which required encoding and mapping of one relation (e.g., the cup at the table's edge). Results showed that children's success was constellation dependent; performance was higher when the arrays were aligned one behind the other in two rows than when they were placed side by side. Furthermore, children showed a preference for landmark mapping over aligned mapping.     

Barriers and traps: great apes’ performance in two functionally equivalent tasks

Tool-using tasks that require subjects to overcome the obstacles to get a reward have been a major component of research investigating causal knowledge in primates. Much of the debate in this research has focused on whether subjects simply use certain stimulus features or instead use more functionally relevant information regarding the effect that certain features may have on a moving reward. Here, we presented two obstacle tasks, a trap platform and a barrier platform, to 22 great apes. Although perceptually similar, these two tasks contain two perceptually different but functionally equivalent obstacles: a trap and a barrier. In a pre-exposure phase, subjects either experienced an obstacle task or a task without any obstacle. In the transfer phase, all subjects were presented with an obstacle task, either the trap platform or the barrier platform. Our results show that those subjects who received an obstacle task prior to the second task performed better than those who first received a non-obstacle task. The type of obstacle task that subjects received first did not have any effect on their performance in the transfer phase. We suggest that apes possess some knowledge about the effects that obstacles have on slow-moving unsupported objects.     

Problem solving in great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo abelii): the effect of visual feedback

What kind of information animals use when solving problems is a controversial topic. Previous research suggests that, in some situations, great apes prefer to use causally relevant cues over arbitrary ones. To further examine to what extent great apes are able to use information about causal relations, we presented three different puzzle box problems to the four nonhuman great ape species. Of primary interest here was a comparison between one group of apes that received visual access to the functional mechanisms of the puzzle boxes and one group that did not. Apes' performance in the first two, less complex puzzle boxes revealed that they are able to solve such problems by means of trial-and-error learning, requiring no information about the causal structure of the problem. However, visual inspection of the functional mechanisms of the puzzle boxes reduced the amount of time needed to solve the problems. In the case of the most complex problem, which required the use of a crank, visual feedback about what happened when the handle of the crank was turned was necessary for the apes to solve the task. Once the solution was acquired, however, visual feedback was no longer required. We conclude that visual feedback about the consequences of their actions helps great apes to solve complex problems. As the crank task matches the basic requirements of vertical string pulling in birds, the present results are discussed in light of recent findings with corvids.     

Apes are intuitive statisticians

Inductive learning and reasoning, as we use it both in everyday life and in science, is characterized by flexible inferences based on statistical information: inferences from populations to samples and vice versa. Many forms of such statistical reasoning have been found to develop late in human ontogeny, depending on formal education and language, and to be fragile even in adults. New revolutionary research, however, suggests that even preverbal human infants make use of intuitive statistics. Here, we conducted the first investigation of such intuitive statistical reasoning with non-human primates. In a series of 7 experiments, Bonobos, Chimpanzees, Gorillas and Orangutans drew flexible statistical inferences from populations to samples. These inferences, furthermore, were truly based on statistical information regarding the relative frequency distributions in a population, and not on absolute frequencies. Intuitive statistics in its most basic form is thus an evolutionarily more ancient rather than a uniquely human capacity.     

Domestic dogs (Canis familiaris) coordinate their actions in a problem-solving task

Cooperative hunting is a cognitively challenging activity since individuals have to coordinate movements with a partner and at the same time react to the prey. Domestic dogs evolved from wolves, who engage in cooperative hunting regularly, but it is not clear whether dogs have kept their cooperative hunting skills. We presented pairs of dogs with a reward behind a fence with two openings in it. A sliding door operated by the experimenter could block one opening but not both simultaneously. The dogs needed to coordinate their actions, so that each was in front of a different opening, if one of them was to cross through and get food. All 24 dog pairs solved the problem. In study 1, we demonstrated that dogs understood how the apparatus worked. In study 2, we found that, although the performance of the pairs did not depend on the divisibility of the reward, pairs were quicker at coordinating their actions when both anticipated rewards. However, the dogs did not monitor one another, suggesting that their solutions were achieved by each individual attempting to maximize for itself.     

Domestic dogs conceal auditory but not visual information from others

A number of studies have shown that dogs are sensitive to a human’s perspective, but it remains unclear whether they use an egocentric strategy to assess what humans perceive. We investigated whether dogs know what a human can see and hear, even when the dogs themselves are unable to see the human. Dogs faced a task in which forbidden food was placed in a tunnel that they could retrieve by using their paw. Whereas the dogs could not see the experimenter during their food retrieval attempts, the experimenter could potentially see the dog’s paw. In the first experiment, dogs could choose between an opaque and a transparent side of the tunnel, and in the second experiment, they could choose between a silent and a noisy approach to the tunnel. The results showed that dogs preferred a silent approach to forbidden food but they did not hide their approach when they could not see a human present. We conclude that dogs probably rely on what they themselves can perceive when they assess what the human can see and hear.     

An assessment of antecedent events influencing noncompliance in an outpatient clinic

Several studies have shown that various factors can influence noncompliance, including task novelty, rate of presentation, and task preference. This study examined the impact of selected antecedent variables on noncompliance in an outpatient clinic setting. In two experiments involving 6 typically developing children, the consequences for noncompliance remained constant. During Experiment 1, demands that included noncontingent access to adult attention were contrasted with the same demands that did not include attention within a multielement design. In Experiment 2, demands were altered by decreasing the difficulty or amount of work or providing access to attention. In both experiments, results indicated idiosyncratic responses to the manipulated variables, with decreases in noncompliance observed following introduction of one or more antecedent variables with 5 of the 6 participants. These results suggested that noncompliance can be reduced via changes in antecedent variables, including adding potential positive reinforcers to the task situation, and that it is possible to probe variables that alter noncompliance in an outpatient clinic setting.