Strategies in probabilistic categorization: results from a new way of analyzing performance

The "Weather Prediction" task is a widely used task for investigating probabilistic category learning, in which various cues are probabilistically (but not perfectly) predictive of class membership. This means that a given combination of cues sometimes belongs to one class and sometimes to another. Prior studies showed that subjects can improve their performance with training, and that there is considerable individual variation in the strategies subjects use to approach this task. Here, we discuss a recently introduced analysis of probabilistic categorization, which attempts to identify the strategy followed by a participant. Monte Carlo simulations show that the analysis can, indeed, reliably identify such a strategy if it is used, and can identify switches from one strategy to another. Analysis of data from normal young adults shows that the fitted strategy can predict subsequent responses. Moreover, learning is shown to be highly nonlinear in probabilistic categorization. Analysis of performance of patients with dense memory impairments due to hippocampal damage shows that although these patients can change strategies, they are as likely to fall back to an inferior strategy as to move to more optimal ones.     

Sickle cell disease as a neurodevelopmental disorder

Sickle cell disease (SCD) is a blood disorder; however, the central nervous system (CNS) is one of the organs frequently affected by the disease. Brain disease can begin early in life and often leads to neurocognitive dysfunction. Approximately one-fourth to one-third of children with SCD have some form of CNS effects from the disease, which typically manifest as deficits in specific cognitive domains and academic difficulties. We discuss SCD as a neurodevelopmental disorder by reviewing the mechanisms of neurological morbidity in SCD, the timing of these mechanisms, the types of cognitive and behavioral morbidity that is typical, and the interaction of social-environmental context with disease processes. The impact of the disease on families shares many features similar to other neurodevelopmental disorders; however, social-environmental factors related to low socioeconomic status, worry and concerns about social stigma, and recurrent, unpredictable medical complications can be sources of relatively higher stress in SCD. Greater public awareness of the neurocognitive effects of SCD and their impact on child outcomes is a critical step toward improved treatment, adaptation to illness, and quality of life.     

Inter- and intra-group variability in perceptions of behavior among Asian Americans and European Americans

Between-group and within-group differences in perceptions of behavior were examined among 74 Asian Americans and 111 European Americans. Participants rated videotaped interactions of Asian American mothers and daughters. Asian Americans, and a more homogeneous sample of Chinese Americans, perceived less maternal control and more reciprocity than did European Americans. Intra-cultural variations in perceptions were also evident, as within-group analyses revealed differences in perceptions based on the generational status of Asian Americans and the degree of multicultural experience of European Americans. Overall, findings suggest that perceptions of behavior are shaped as much by within-group differences in familiarity and experience with the target culture as by between-group differences in ethnicity. Implications for theories of child socialization, multicultural counseling, and observational research are discussed.     

The concept of risk and responsible conduct of research

Assessment of risk is one of the key issues in the field of responsible conduct of research which covers discourses of research ethics and research integrity. The principle of minimizing risks and balancing of risks and benefits is one of the main requirements of research ethics. In addition, the content of informed consent that is another fundamental principle of research ethics derives from the assessment of risks and benefits related to a particular research project. Risk assessment also plays a crucial role in methodological design of the research project. This is an important point where research ethics and research integrity discourses overlap. Firstly, because the choice of a control group (e.g., placebo control) is a key ethical issue related to the protection of the research subjects' interests. Secondly, because the quality of the research data, that is one of the key elements of research integrity, is closely connected to the choice of research methodology as well. The problem of biased interpretation or manipulation of risk related features of biomedical research should also be taken into account. Despite the importance of the concept of risk to the field of biomedical research, its relevance has not yet attracted a sufficient attention in the responsible conduct of research debate.     

The protection of patients’ rights in clinical trials

The Helsinki Declaration is a very important document regarding the protection of patients’ rights in clinical trials and one of the fundamental sources of operational principles for every ethics committee. Although they have been updated, the international guidelines for ethics committees continually fail to address certain issues pertaining to the protection of patients’ rights in clinical trials. These issues include, most significantly, the method of electing ethics committees (a free, secret ballot should be preferred to direct appointment), the avoidance of conflict of interest during the election of ethics committee members, and the necessary insurance coverage for the participants of clinical trials. Polish law should, on the other hand, be developed in such way as to not limit the effectiveness of ethics committees in protecting patients’ rights in clinical trials. The ideal solution would be to draft a uniform law concerning not only clinical trials, but all medical experiments. The opinions of experts who have been reviewing medical research projects for several years may prove to be especially valuable in this setting. This paper was presented at the 6th International Bioethics Conference on the subject of ‘The Responsible Conduct of Basic and Clinical Research’, held in Warsaw, Poland, 3–4 June 2005. The author is Chairman, Bioethics Committee of the Warsaw Regional Chamber of Physicians and Dentists.     

The mentor and the trainee in academic clinical medicine

Medicine is a scientific discipline, but it is sometimes difficult to separate what is scientific and what is a clinical, practical activity. Man is the object, but he is always the subject of medical research and therefore these two elements become closely bound together by a thread of moral interdependencies. Every mentor of a young academic and all institutions dealing with the teaching of and research into medicine must understand multidimensional, multifaceted, and multilevel aspects of their activity and give them due regard in the educational process. The educational mission of an academic institution and of the teacher working there may be summed up in one phrase: Teach thinking! At the same time, the task of a school and the individual mentor is to teach the student to distinguish personal freedom from a lack of the feeling of responsibility. The medieval principle “Universitas magistrorum et scholarium”, and thus the corporation, the community of teachers and students, has not lost any of its relevance and value today. The situation is, in its far-reaching consequences, tragic in which the “insufficiently tutored teach”. Both physician and teacher, and especially physician-teacher, are not only professions, but also callings. This paper was presented at the 6th International Bioethics Conference on the subject of ‘The Responsible Conduct of Basic and Clinical Research’, held in Warsaw, Poland, 3–4 June 2005.     

Spatial encoding by bumblebees (Bombus impatiens) of a reward within an artificial flower array

We presented bumblebees a spatial memory task similar to that used with other species (e.g., cats, dogs, and pigeons). In some conditions we allowed for presence of scent marks in addition to placing local and global spatial cues in conflict. Bumblebees (Bombus impatiens) were presented an array of artificial flowers within a flight cage, one flower offering reward (S+), while the others were empty (S−). Bees were tested with empty flowers. In Experiment 1, flowers were either moved at the time of testing or not. Bees returned to the flower in the same absolute position of the S+ (the flower-array-independent (FAI) position), even if it was in the wrong position relative to the S− and even when new flower covers prevented the use of possible scent marks. New flower covers (i.e., without possible scent marks) had the effect of lowering the frequency of probing behavior. In Experiment 2, the colony was moved between training and testing. Again, bees chose the flower in the FAI position of the S+, and not the flower that would be chosen using strictly memory for a flight vector. Together, these experiments show that to locate the S+ bees did not rely on scent marks nor the positions of the S−, though the S− were prominent objects close to the goal. Also, bees selected environmental features to remember the position of the S+ instead of relying upon a purely egocentric point of view. Similarities with honeybees and vertebrates are discussed, as well as possible encoding mechanisms.     

Social perspective-taking skills in maltreated children and adolescents

The primary goal of this study was to assess the ability of maltreated school-age children and adolescents to understand the thoughts, feelings, and points of view of others. Level of egocentrism and social perspective-taking coordination were assessed in a group of 49 maltreated and 49 demographically matched nonmaltreated children. Twenty-six elementary and 23 high school students in each group were individually interviewed and their responses to hypothetical interpersonal situations coded for egocentricity and level of perspective-taking ability. The findings revealed that maltreated children and adolescents were more egocentric and delayed in their social perspective-taking development than their nonmaltreated peers and that they reported lower levels of global self-worth. However, differences within the group of maltreated children and adolescents emerged with regard to negotiating novel relationships, as those with fewer internalizing or externalizing symptoms exhibited better skills in this area than their peers who displayed more symptoms.     

Violent self-harm in schizophrenia

Patients with schizophrenia have a substantial lifetime suicide risk, especially by violent means. Little published work exists on self-harm (SH) in this population. The goal of this study was to examine whether patients with schizophrenia were also more likely to self-harm in a violent manner. A retrospective analysis performed on method, motive, and suicidal intent in patients with schizophrenia (n = 50) and adjustment reaction (n = 138) who presented with SH over a 3-year period found that there was no significant difference between the two groups in terms of violence of method or suicidal intent. Presence of positive symptoms of schizophrenia was not significantly associated with use of a violent method. This study suggests that the expected pattern of violent SH in schizophrenia is inaccurate and for the majority the acts are of a similar nature to those seen in adjustment reactions.     

Becoming a face expert

Expertise in recognizing facial identity, and, in particular, sensitivity to subtle differences in the spacing among facial features, improves into adolescence. To assess the influence of experience, we tested adults and 8-year-olds with faces differing only in the spacing of facial features. Stimuli were human adult, human 8-year-old, and monkey faces. We show that adults' expertise is shaped by experience: They were 9% more accurate in seeing differences in the spacing of features in upright human faces than in upright monkey faces. Eight-year-olds were 14% less accurate than adults for both human and monkey faces (Experiment 1), and their accuracy for human faces was not higher for children's faces than for adults' faces (Experiment 2). The results indicate that improvements in face recognition after age 8 are not related to experience with human faces and may be related to general improvements in memory or in perception (e.g., hyperacuity and spatial integration).