The Effect of Information Strength and Weight on Behavior in Financial Markets

Griffin and Tversky (1992) explain evidence of individual over- and underconfidence as resulting from attending too much to the strength (i.e., extremity) of information and not enough to the weight (i.e., statistical reliability) of information. We report two experiments that demonstrate how information strength and weight affect confidence, trading, prices, and wealth in laboratory markets. Our results indicate that information strength and weight affect individual over- and underconfidence and that market participants lack sufficient self-insight to avoid trading when they are biased. As a consequence, market prices are biased, and market participants with high-strength, low-weight information systematically transfer wealth to participants with low-strength, high-weight information.     

Unrecognized Changes in the Self Contribute to Exaggerated Judgments of External Decline

People commonly perceive social conditions as declining. We propose that perceptions of social decline are often a consequence of a bias whereby people mistake change in themselves for change in the world. The present research demonstrates that common personal changes such as the parenthood transition (Studies 1–2) and physical aging (Study 3) may increase a person's sensitivity to dangers and thereby contribute to an illusory perception that external dangers are increasing. We use experimental models of the hypothesized change processes to test whether these common personal changes may contribute to judgments of social decline.     

From Mental Health to Juvenile Justice: What Factors Predict This Transition?

We identify youth who are at risk for a critical transition from mental health to juvenile justice. A statewide longitudinal sample of Medicaid-eligible youth (aged 10–17) in the public mental health system (n = 5,455), during approximately one fiscal year (July 1, 1994–August 30, 1995), was used to determine the risk factors for, and timing of, a subsequent juvenile justice detention or commitment during the three subsequent fiscal years (1994–1997). Logistic regression and Cox Proportional Hazards modeling were used. Risk factors for juvenile justice detention or commitment included being: male, black or Hispanic, in junior high school, involuntarily admitted to mental health, having a DSM-IV diagnosis of conduct disorder, alcohol problems, a constellation of risk behavior, and receiving prior mental health services. Factors that accelerate the timing of detention or commitment in the juvenile justice system after a mental health visit included most of the general risk factors except risk behavior and involuntary admission were no longer significant and having a DSM-IV nonalcohol drug use diagnosis, antisocial behavior, and school problems became significant. Our study helps to identify youth who are at risk for multiple system use so that they may be provided appropriate services to prevent multiple system use.     

Structure and strategy in the associative false memory paradigm

List-learning experiments can have several levels of structure: individual words, the gist (if any) of each list, and the task in which those lists are embedded. The usual presentation of the DRM associative paradigm (Deese, 1959; Roediger & McDermott, 1995) strongly encourages a focus on gist and produces a high rate of false recall of key words (FRK). The experiments reported here were designed to invite the use of memory strategies based on structures other than the gist and thus reduce FRK. The crucial condition of Experiment 1, short lists followed by rehearsal, encouraged a focus on individual words and produced a low rate of FRK. In Experiment 2, the lists were embedded in a guessing game, which virtually eliminated FRK. FRK was also low in Experiments 3a and 3b when participants engaged in a complex task involving the first letters of list words. The relevance of these findings to false memories in the DRM and the connection of false autobiographical memories is discussed.     

Timing of avoidance responses by rats

Three rats were trained on an unsignalled shuttlebox-avoidance task under three response-shock intervals (10, 20, and 40 sec). Under all conditions, subjects developed excellent temporal gradients of avoidance; that is, response rate was an increasing function of time since last response. Although the response rate at any given interval of time after the previous response was inversely related to the response-shock interval, there was an underlying similarity in the temporal gradients for the three intervals. In all cases, response rate relative to the maximum response rate was approximately equal to the proportion of the interval that had elapsed. This suggests that rats in unsignalled avoidance are estimating time from response completion, and that the units of the estimate are proportional parts of the response-shock interval.     

Group performance as a function of group type,task condition and scholastic level

Studied performance on a multiple-solution anagrams task by two-member nominal, pseudo, quasi, and real groups in relation to task conditions (set versus nonset) and school grades (10th, 11th, and 12th). Nominal groups were made up of individuals working alone. Pseudo groups were made up of members sitting together but working independently for individual scores. Quasi groups were made up of members who were working together for a common or shared goal but were not allowed to communicate with each other. Real groups were the usual teams of freely interacting and mutually consulting members. Five words were presented to the subjects in the set condition (unlike in the nonset co ndition) in order to channelize their problem-solving activity in particular directions. The subjects were 192 male American high school students. The most important finding was that both nominal and pseudo groups produced more errors than real groups. Also the set condition generated more errors than the nonset condition. These and other findings were discussed and interpreted in the context of previous research.     

Islamic Trauma Healing: Integrating Faith and Empirically Supported Principles in a Community-Based Program

Access to adequate, much less state-of-the-art, mental health care is a global problem. Natural disasters, civil war, and terrorist conflict have forcibly displaced millions of Muslims and have resulted in a remarkable level of individual and communitywide trauma exposure. As a result, many are at risk for posttraumatic stress and other trauma-related disorders. Many religiously oriented Muslims traditionally rely on Islamic principles and teachings, as well as their community, to cope with and address trauma-related distress. Islamic Trauma Healing is a six-session, lay-led group intervention developed within a Somali Muslim community that integrates evidence-based trauma-focused cognitive-behavioral therapy principles with cultural and religious practices aimed to enhance uptake and create an easily up-scalable intervention for a wide range of trauma. In sessions, narratives of prophets who have undergone trauma (e.g., Prophet Ayyub, faith during hard times) present Islamic principles and facilitate cognitive shifts. Group members spend individual time turning to Allah in dua (i.e., informal prayer), focused on exposure to trauma memories. Program themes arc across suffering to healing to growth following trauma. This paper describes the core theoretical principles and methods in the Islamic Trauma Healing program. We also describe leader perspectives and the program’s train-the-trainer model, in which lay leaders are trained to further disseminate the program and allow Islamic Trauma Healing to be owned and sustained by the Muslim community.     

Hair today, gone tomorrow: a comparison of body hair removal practices in gay and heterosexual men

Although hairlessness is rapidly becoming a component of the ideal male body, little research has examined men's concerns about their body hair or their hair removal practices. Samples of gay and heterosexual men completed questionnaires that assessed whether they had ever removed their back, buttock or pubic hair, the frequency with which they did so, the methods used and their self-reported reasons for removing this hair, as well as their level of appearance investment. Results indicated that many gay and heterosexual men remove their back, buttock and pubic hair regularly and that their primary reason for doing so is to maintain or improve their appearance. The frequency of hair removal was also associated with the motivational salience component of appearance investment. The findings offer further support to the premise that gay and heterosexual men exhibit similar body image concerns.     

Gender Discrimination as a Function of Stereotypic and Counterstereotypic Behavior: A Cross-Cultural Study

This study investigated gender discriminatory behavior of early adolescents from a cross-cultural perspective. One hundred sixty 7th-graders (80 Israeli Arabs and 80 Israeli Jews) were presented with two male candidates for class representative, one outstanding candidate with traditional feminine interests and characteristics, and the other an average candidate with masculine interests and characteristics. Participants were asked to rate the candidates on various measures such as their own election choice, others' election choice, their prediction of the candidate's likelihood of being elected, and their affinity and willingness to engage in activities with the candidate. The results showed that while both Arab and Jewish participants discriminated against the feminine candidate, the Arab participants discriminated to a much greater degree. The results emphasize the important role that culture plays in gender discriminatory behavior.