Concept Discovery in a Scientific Domain

The scientific reasoning strategies used to discover a new concept in a scientific domain were investigated in two studies. An innovative task in which subjects discover new concepts in molecular biology was used. This task was based upon one set of experiments that Jacob and Monod used to discover how genes are controlled, and for which they were awarded the Nobel prize. In the two studies reported in this article, subjects were taught some basic facts and experimental techniques in molecular biology, using a simulated molecular genetics laboratory on a computer. Following their initial training, they were then asked to discover how genes are controlled by other genes. In Study 1, subjects found no evidence that was consistent with their initial hypothesis. Subjects then set one of two goals for conducting experiments and evaluating data. One goal was to search for evidence consistent with the current hypothesis (and they did not attend to the features of discrepant findings); none of the subjects who only had this goal succeeded at discovering how the genes were controlled. Other subjects in Study 1 used a different goal: Upon noticing evidence inconsistent with their current hypothesis, these subjects set a new goal of attempting to explain the cause of the discrepant findings. Using this goal, a subset of these subjects discovered the correct solution to the problem. Study 2 was conducted to test the hypothesis that subjects' goals of finding evidence consistent with their current hypothesis blocks consideration of alternate hypotheses and generation of new goals, it was predicted that if subjects could achieve their initial goal of discovering evidence consistent with their current hypothesis, they would then attend to particular features of discrepant evidence and solve the problem. To test this prediction, an additional mechanism of genetic control that was consistent with subjects' initial goal was added to the genes. Here, subjects had to discover two mechanisms of control: one mechanism consistent with their current hypothesis, and one inconsistent with their hypothesis. Twice as many subjects reached the correct solution in Study 2 than in Study 1. The findings of the two studies indicate that goals provide a powerful constraint on the cognitive processes underlying scientific reasoning and that the types of goals that are represented determine many of the reasoning errors that subjects make.     

Separating the reinforcing and discriminative properties of brief-stimulus presentations in second-order schedules.

Pigeons' responses were maintained under multiple schedules to study properties of briefly presented stimuli. Responses in one component produced food according to a second-order schedule with fixed-interval components in which food or a brief stimulus occurred with equal probability. In the second component responses produced only the brief stimulus under a fixed-ratio schedule. Under various conditions the brief stimulus in the first component was (a) paired with food, (b) not paired with food, (c) partially omitted, or (d) scheduled simultaneously with the second-order schedule under an independent variable-interval schedule. Paired and nonpaired brief stimuli maintained similar response patterning in the second-order schedule. However, only paired stimuli maintained responses in the second component. The data suggest that nonpaired brief stimuli engender response patterning in second-order schedules as a result of their discriminative properties. When the stimulus is paired with food, these discriminative properties sometime mask a reinforcement effect, and no change in response patterning is observed. When the discriminative properties of the brief stimulus are absent, the reinforcing effects of pairing the brief stimulus with food may be observed.     

Under Reporting of Suicide Ideation in US Army Population Screening: An Ongoing Challenge

Previous research in US Army Soldiers shows rates of mental health concerns as two to four times higher on anonymous surveys than on postdeployment health assessments. In this study, Soldiers presenting for health reassessment completed two questionnaires on suicide risk factors: one linked to the health assessment and one anonymous. About 5.1% of respondents reported suicide ideation on the anonymous questionnaire, 3.0% on the linked questionnaire, and 0.9% on the health reassessment. About 56.4% who reported suicide ideation anonymously told nobody of their thoughts. Current screening procedures identify only one in seven Soldiers experiencing suicide ideation and highlight the need for alternative risk‐detection strategies.     

Risk Factors of a Suicide Reattempt by Seasonality and the Method of a Previous Suicide Attempt: A Cohort Study in a Japanese Primary Care Hospital

Suicide has a great impact on the individual whose life is lost and the bereaved family members. The risk of a suicide reattempt is particularly high during the first 12 months after a suicide attempt. In this cohort study, risk factors for a suicide reattempt were explored among 291 patients at suicide risk. Clinical and demographic data were collected from a Japanese primary care hospital. Past psychiatric history and multiple diagnoses were associated with suicide reattempts in both genders. Drug overdose, past psychiatric history, and the summer season were linked to suicide reattempts among males. Past psychiatric history and multiple diagnoses were linked to suicide reattempts among females. Appropriate assessment of past psychiatric history, season and method of suicide attempt, gender, and diagnosis may play a role in preventing suicide.     

Nonsuicidal Self‐Injury in Adolescents: Characterization of the Disorder and the Issue of Distress and Impairment

Nonsuicidal self‐injury disorder (NSSID) is a condition in need of further study to assess the validity of the potential diagnosis and its suggested criteria. This study examined the NSSID diagnosis and investigated the distress/impairment criterion by comparing community adolescents who met all criteria for NSSID (n = 186) to adolescents with five or more nonsuicidal self‐injury (NSSI) episodes (n = 314), and to a group of adolescents who met all criteria but negated that their NSSI caused them any distress or impairment, thus failing to meet criterion E (n = 29). The NSSID group delimited from the ≥ 5 NSSI group by reporting significantly more frequent and severe self‐injurious thoughts and behaviors, as well as having more experiences of negative life events and higher levels of trauma symptoms. There were also some differences between the NSSID group and adolescents without distress/impairment, which together contribute valuable information on the potential NSSID diagnosis, as well as the discussion of criterion E.