Model Existence in Non-Compact Modal Logic

Predicate modal logics based on Kwith non-compact extra axioms are discussed and a sufficient condition for the model existence theorem is presented. We deal with various axioms in a general way by an algebraic method, instead of discussing concrete non-compact axioms one by one.     

Thought control strategies as mediators of trauma symptoms in young women with histories of child sexual abuse

The current retrospective study examined thought control strategies, or cognitive techniques individuals use to deal with unpleasant thoughts following stressful events, as potential mediators of adjustment in young women with histories of child sexual abuse (CSA). In a sample of 76 undergraduate women who self-reported on abuse experiences, thought control strategies, and current trauma symptoms, several key findings emerged: (i) Greater severity of the CSA event was associated with greater reported use of worry and punishment strategies and less use of social control strategies; (ii) Increased use of worry and punishment strategies following the CSA event was associated with greater levels of trauma symptoms, while increased use of social control strategies following the CSA event was associated with lower levels of trauma symptoms; and (iii) Worry, punishment, and social control strategies served as mediators between CSA severity and trauma symptoms. The results suggest that thought control strategies, specifically increased worry and punishment, and decreased social control, play a vital role in understanding adjustment after CSA. Future research should examine the roles of these cognitive control strategies as possible avenues of intervention following CSA.     

Token transfer between mother and offspring chimpanzees (Pan troglodytes): mother–offspring interaction in a competitive situation

Chimpanzees can flexibly use tokens in cognitive tasks, but it is still unknown if they can share and/or compete over tokens as they do for food. This study aimed to evaluate the interactions spontaneously occurring between mother and offspring chimpanzees when tokens exchangeable for food were provided. Forty tokens were scattered on the floor in an experimental playroom. Three mother and offspring chimpanzee pairs were tested. Each token was exchangeable for a piece of food in a vending machine installed on the wall of the playroom. In the beginning of the study, both mother and offspring took tokens and exchanged them for pieces of food independently. Later, two offspring started to take more tokens than their mothers. At that time, the offspring whimpered or cried more often than during earlier sessions. This behavior compelled the mothers to abstain from taking tokens. The mothers sometimes shared their tokens with their offspring, or were tolerant of their offspring taking their tokens from their hand. For one pair, the offspring sometimes shared tokens with her mother when her mother begged for the tokens. These results suggest that chimpanzees’ cognitive abilities enable them not only to use tokens, but also to compete for tokens, as they do for food. The results also suggest that token sharing between mother and offspring may be bidirectional and that transfer of tokens mainly occurs as a result of begging, although on some occasion offspring were able to obtain a token directly from his/her mother through tolerated scrounging.     

Selfish strategies develop in social problem situations in chimpanzee (Pan troglodytes) mother–infant pairs

Humans employ various strategies, including selfish and altruistic strategies, depending on the situation. In order to examine whether non-human animals show such flexibility or not, we analyzed chimpanzees’ selfish and cooperative behavior in two types of social problem situations. In this study, we tested chimpanzee mother–infant pairs in two adjacent booths, each equipped with a vending machine. When a token was inserted into a vending machine, the vending machine delivered food rewards to the adjacent booth. In experiment 1, a partition between the two booths was open. In experiment 2, the partition was closed and a mother and her infant were placed in separate booths, so that reciprocal cooperation was essential for them to receive rewards. The participants did not cooperate reciprocally in either experiment. In experiment 1, the chimpanzees developed selfish tactics to get rewards and changed their tactics flexibly according to the partner’s behaviors. In experiment 2, in which they could not receive rewards without cooperation, they stopped altogether inserting tokens. In both cases, the infants stopped cooperating first. These findings support the idea that chimpanzees are primarily competitive rather than cooperative. Chimpanzees’ high social intelligence might be demonstrated in the flexibility of their selfish tactics, but not in the form of reciprocal cooperation at least when food is involved. We suggest that the failure to establish reciprocal cooperation was due to the social relationship between the mother and her infant, which was characterized by infant’s privilege and mother’s tolerance.     

The neural plasticity of other-race face recognition

Although it is well established that people are better at recognizing own-race faces than at recognizing other-race faces, the neural mechanisms mediating this advantage are not well understood. In this study, Caucasian participants were trained to differentiate African American (or Hispanic) faces at the individual level (e.g., Joe, Bob) and to categorize Hispanic (or African American) faces at the basic level of race (e.g., Hispanic, African American). Behaviorally, subordinate-level individuation training led to improved performance on a posttraining recognition test, relative to basic-level training. As measured by event-related potentials, subordinate- and basic-level training had relatively little effect on the face N170 component. However, as compared with basic-level training, subordinate-level training elicited an increased response in the posterior expert N250 component. These results demonstrate that learning to discriminate other-race faces at the subordinate level of the individual leads to improved recognition and enhanced activation of the expert N250 component.     

Impaired Interpretation of Others’ Behavior is Associated with Difficulties in Recognizing Pragmatic Language in Patients with Schizophrenia

Much attention has been paid to the pragmatic language function in schizophrenia. This study of Japanese patients with schizophrenia examined the relationship between impaired interpretation of the behaviors of other people in social contexts and the ability to recognize metaphor and irony. We assessed 34 patients with schizophrenia and 34 normal subjects using first- and second-order theory of mind tasks, the Metaphor and Sarcasm Scenario Test, and the Dewey Story Test (which tests the ability to judge others’ social behaviors). We compared the performance between the groups and analyzed correlations between the tasks. All tasks revealed significant deficits in the patients compared with the controls. In the patient group, metaphor comprehension was correlated with the ability to judge normal behaviors, and irony comprehension was correlated with the ability to judge abnormal behaviors, suggesting that deficits of social cognition in schizophrenia include these two types of factors associated with pragmatic language.     

A case report of compensation in daily life of a person with memory problems: detailed functional use of memory aids over a five-year period

Numerous studies have been conducted on memory aids for memory-impaired people. However, it is not known how they use these memory aids in a functional, practical way. A 20-year-old patient (MH) was monitored for five years to identify what memory aids or other means she used and how she used them to compensate for her memory problems, e.g., forgetting what was said by others in a few minutes and getting lost or turning in the wrong direction on a walk or in a building. Results indicated MH did not necessarily always use memory aids such as a notebook or calendar to compensate for her memory problems, although MH and her mother reported that she frequently used them in daily life. She coped with memory problems by using various "resources" besides the memory aid. These facts suggest that it may be necessary to redefine functionally useful compensations, which include both memory aids and resources in daily life.     

Early development of perceptual expertise: Within-basic-level categorization experience facilitates the formation of subordinate-level category representations in 6- to 7-month-old infants

A behavioral manifestation of perceptual expertise is the shift in recognition downward toward the subordinate level. Here, a familiarization-novelty preference procedure was used to determine whether 6- to 7-month-old infants could be induced to form category representations for cats and dogs at the subordinate level. In Experiment 1, the infants succeeded in forming subordinate-level category representations for beagle dogs and Siamese cats, but only when provided with previous experience on a subordinate-level category-formation task from within the same basic-level category (i.e., Saint Bernard dogs or tabby cats). When the prior category-formation task involved a different basic-level category, subsequent subordinate-level category learning was not in evidence. The preferences in Experiment 1 were shown in Experiments 2 and 3 not to be attributable to a priori preference or within-category discrimination failure. The findings suggest that within-basic-level categorization experience can facilitate the formation of subordinate-level category representations in the first half-year of life.     

Spontaneously occurring mother-infant swapping and the relationships of infants with their biological and foster mothers in a captive group of lowland gorillas (Gorilla gorilla gorilla)

The present study describes spontaneously occurring infant-mother swapping and the relationships of infants with their biological and foster mothers after swapping in a captive social group of lowland gorillas (Gorilla gorilla gorilla). After infant-swapping took place between a primiparous mother with a neonate and a multiparous mother with a 10-month-old infant, the mothers provided appropriate maternal care, including nursing, to their adopted infants, but the older infant still sought refuge with its biological mother more frequently than with its foster mother. Almost 2 years later, the younger infant who was weaned by its foster mother began nursing from its biological mother; the latter subsequently weaned her adopted infant. Thereafter, the older infant who was weaned exhibited an abnormal hair-plucking behavior. These results indicate that it was psychologically stressful for the gorilla infant to quickly transfer its attachment figure from the mother to another adult female when the mother continued to remain in the group.     

Gravity bias in young and adult chimpanzees (Pan troglodytes): tests with a modified opaque-tubes task

Young human children at around 2 years of age fail to predict the correct location of an object when it is dropped from the top of an S-shape opaque tube. They search in the location just below the releasing point (Hood, 1995). This type of error, called a 'gravity bias', has recently been reported in dogs and monkeys. In the present study, we investigated whether young and adult chimpanzees also show such a gravity bias in a modified version of the original opaque-tube task. The original task by Hood and colleagues required the subject to search in a location after the object had fallen, while in the task reported here, subjects were required to predict the location before the object was dropped. Thus the present procedure does not involve explicit invisible displacement operations, one of the important components of the original procedure. In Experiment 1 both young (1.5-2.5-year-old) and adult chimpanzees predicted the location of falling food items below the releasing point even when crossed tubes were used. These gravity errors remained after the extensive experience of using the tubes themselves. Experiment 2 further tested adult and 4-year-old chimpanzees under the set-up in which the straight and crossed tubes were simultaneously presented. The results were the same as those in the previous test, suggesting that developmental changes and learning effect do not affect the gravity bias in chimpanzees.