A Capuchin monkey (<Emphasis Type="Italic">Cebus apella</Emphasis>) recognizes when people do and do not know the location of food

In a previous study, Kuroshima and colleagues demonstrated that capuchin monkeys (Cebus apella) learned to discriminate between a "knower" who inspected a box for food, and a "guesser" who did not. The aim of the present study was to specify whether the subjects learned a simple conditional discrimination or a causal relationship that seeing leads to knowing. In experiment 1, we introduced five types of novel containers to two subjects. Each container was of different shape and color. The subjects gradually learned to reach toward the container the knower suggested. In experiment 2, we diversified the behavior of the knower and the guesser. In experiment 3, in order to eliminate the possibility of discrimination based on differences in the magnitude and the complexity of two trainers, we equated their behaviors. One subject adapted to the novel behaviors of the knower and the guesser, successfully discriminating the two trainers. Thus this monkey clearly learned to use the inspecting action of the knower and the non-inspecting action of the guesser as a discriminative cue to recognize the baited container. This result suggests that one capuchin monkey learned to recognize the relationship between seeing and knowing.     

10‐month‐old infants’ inference of invisible agent: Distinction in causality between object motion and human action1

Abstract: Two habituation experiments investigated 10‐month‐old infants’ interpretation of events where a stationary object began to move without any visible causes. During habituation, infants saw that an object partly hidden by an occluder began to move away from the occluder. Then, they were tested with three test events without the occluder: the ?rst event showed a hand pushing the object, the second event showed a hand failing to touch the object, and the last event had no agent. The objects were a ball in Experiment 1, and a person in Experiment 2. The test event that the infants looked at for the shortest duration in Experiment 1 was where the hand pushed the ball, whereas they looked at the three test events almost equal amounts of time in Experiment 2. These results indicate that 10‐month‐old infants responded to the events in terms of causality and could infer the presence of the agent behind the occluder only when they saw the habituation event featuring the ball.     

Effects of ratio reinforcement schedules on discrimination performance by Japanese monkeys

In Experiment 1, Japanese monkeys were trained on three conditional position-discrimination problems with colors as the conditional cues. Within each session, each problem was presented for two blocks of ten reinforcements; correct responses were reinforced under continuous-reinforcement, fixed-ratio 5, and variable-ratio 5 schedules, each assigned to one of the three problems. The assignment of schedules to problems was rotated a total of three times (15 sessions per assignment) after 30 sessions of acquisition training. Accuracy of discrimination increased to a moderate level with fewer trials under CRF than under ratio schedules. In contrast, the two ratio schedules, fixed and variable, were more effective in maintaining accurate discrimination than was CRF. With further training, as asymptotes were reached, accuracy was less affected by the schedule differences. These results demonstrated an interaction between the effects of reinforcement schedules and the level of acquisition. In Experiment 2, ratio sizes were gradually increased to 30. Discrimination accuracy was maintained until the ratio reached 20; ratio 30 strained the performance. Under FR conditions, accuracy increased as correct choice responses cumulated after reinforcement.     

Inhibition in Goal Systems: A Retrieval-Induced Forgetting Account

In social psychological models of goals, particular means or goals that receive more activation are pursued while their counterparts are “inhibited.” To account for inhibition, these theories emphasize structural distribution of resources and the consequences of goal or means choices. Absent are alternate accounts of inhibition based on memory processes that rely on retrieval or recall of items. We propose that the act of recalling means or goals from memory entails inhibition of competing alternatives. Two experiments using repeated retrieval paradigms present evidence that recalling one means associated with a particular goal inhibits competing means. Moreover, this inhibitory mechanism is sensitive to the structural relationship of goals and means. Implications for models of inhibition in goal pursuit are discussed.     

A Multi-informant Multi-Measure Approach to the Two Factor Model of Emotion with Youth

The two-factor model of emotion clarifies the complexities of the relationship between anxiety and depression through their varying associations with positive and negative affect. Although this model’s structure has been studied in children, the lack of parent report measures on model-specific constructs has thus far prevented a multi-informant perspective on the model. Capitalizing on recent advancements in parent report assessment instruments, the present investigation aimed to confirm the two-factor model of emotion per child self-report; expand the model’s applicability to include parent report; and create a combined-informant model with a large number of parent-child dyad pairs (N?=?610). Structural equation modeling demonstrated good fit within parent and child informant models, but diminished fit for the multi-informant model. These results suggest a high degree of robustness with respect to informant type. Implications for the integration of multi-informant assessment information are discussed.     

Are monkeys aesthetists? Rensch (1957) revisited

Three experiments assessed whether capuchin monkeys (Cebus apella) and squirrel monkeys (Saimiri sciureus) prefer regular and symmetrical visual patterns. Pictorial representations of faces were included in 1 stimulus set. When the monkeys could pick up and manipulate small cards bearing the stimuli, all preferences expressed by capuchins and most of those expressed by squirrel monkeys were for regular stimuli. Symmetry of the patterns was influential but not essential. Some preferences were also found for faces. When images of the patterns were presented on a touch screen, capuchins continued to express preferences especially for regular and symmetrical stimuli, but they showed some avoidance of faces. Squirrel monkeys responded less discriminatingly to the touch screen stimuli. The findings provide support for B. Rensch's (1957) claim that monkeys prefer visual stimuli that humans find aesthetically pleasing.     

Redundant food searches by capuchin monkeys (Cebus apella): a failure of metacognition?

This study investigated capuchin monkeys' understanding of their own visual search behavior as a means to gather information. Five monkeys were presented with three tubes that could be visually searched to determine the location of a bait. The bait's visibility was experimentally manipulated, and the monkeys' spontaneous visual searches before tube selection were analyzed. In Experiment 1, three monkeys selected the baited tube significantly above chance; however, the monkeys also searched transparent tubes. In Experiment 2, a bent tube in which food was never visible was introduced. When the bent tube was baited, the monkeys failed to deduce the bait location and responded randomly. They also continued to look into the bent tube despite not gaining any pertinent information from it. The capuchin monkeys' behavior contrasts with the efficient employment of visual search behavior reported in humans, apes and macaques. This difference is consistent with species-related variations in metacognitive abilities, although other explanations are also possible.     

High-resolution electron microscope studies of irradiation-induced crystalline-to-amorphous transition in boron carbide

Abstract

The crystalline-to-amorphous (C-A) transition in boron carbide induced by 2 MeV electron irradiation was studied by high-resolution electron microscopy. It is revealed that the C-A transition takes place not homogeneously but heterogeneously over the irradiated volume and the volume fraction of the amorphous phase continuously increases with increasing dose of electrons.     

The use of paraprofessionals in crisis intervention

Single-session crisis services by paraprofessionals (graduate students and community volunteers) in the emergency room of a community hospital were offered to 293 clients. These clients were followed-up 6 to 12 months after their last contact and asked about: (1) the effectiveness of the service, (2) their use of referrals, (3) the major source of change in their crisis situation, and (4) their rating of improvement for their presenting problem. There were 104 clients who completed the follow-up. The results support the interpretation that timely intervention by paraprofessionals may have long-lasting results in specific problem areas. A model emphasizing the use of service deliverers as researchers is proposed.