风险投资中的短视效应及理论解释

“投资者难以长远地将多重投资看作整体,而更倾向于分割成单一决策进而表现出每次决策风险规避的现象”被称为风险投资中的短视效应.短视/远视风险投资常通过单一决策/重复决策范式予以研究.大多数的研究发现,在单一决策条件下,投资者接受投资的人数比例或者投资金额低于重复决策条件.短视效应的调节机制有反馈频率、投资灵活性、选择组块、风险状况等.研究者分别提出短视损失厌恶（myopic loss aversion,简称MLA）理论和短视预期理论（myopic prospect theory,MPT）对短视现象进行解释;但这些理论受到基于齐当别理论（equate-to-differentiate theory）研究的挑战.文章在总结短视效应已有相关研究的基础上指出今后有必要深入探索的方向.     

Parental loss of close family members and propensities towards absorption in offspring

Parental unresolved/disorganized responses to loss assessed in the Adult Attachment Interview predict infant disorganized (D) attachment. Parental experiences of loss near the birth of an infant should therefore increase the likelihood of D attachment to that parent. Liotti (1992) suggested that D attachment may increase tendencies to altered states of consciousness, and some support for this hypothesis has been obtained in clinical and high-risk samples. Here, Tellegen's Absorption Scale was used to measure propensities to altered consciousness in two low-risk samples of young adults (N=136, N=308). In both studies, participants whose parents experienced familial loss within two years of their birth showed elevated levels of absorption. These outcomes (a) support the proposed connection between disorganized attachment and tendencies to altered consciousness, and (b) suggest that queries regarding parental loss experiences should be further explored as a ‘rough and ready’ estimate of disorganized attachment in large-scale studies.     

THEORETICAL,PRACTICAL, AND SOCIAL ISSUES IN BEHAVIORAL TREATMENTS OF OBESITY

Although showing superior maintenance, behavioral treatments of obesity typically produce small weight losses at a decelerating rate. Rather than reflecting poor compliance with treatment, these findings are consistent with known compensatory metabolic changes that operate to slow weight loss and promote regain. Other problems associated with dieting include failure of caloric regulation, hyper-responsivity to food palatability, and hunger, which is greatest under conditions of moderate restriction and unpredictability of access to food. The inevitability of treatment failure in many instances must be faced and efforts made to prevent further worsening of the obese patient's self-esteem. Prognosis and treatment planning may be aided by consideration of the historical difficulties of weight loss, the degree of hunger experienced on diets, which may reflect important physiological differences among individuals, and the use of food to optimize arousal level. Full involvement of the patient in setting goals and planning treatment is recommended.     

Contingency-shaped and rule-governed behavior: instructional control of human loss avoidance

Instructions can override the influence of programmed schedules of reinforcement. Although this finding has been interpreted as a limitation of reinforcement schedule control in humans, an alternative approach considers instructional control, itself, as a phenomenon determined by subjects' reinforcement histories. This approach was supported in a series of experiments that studied instructional and schedule control when instructions either did or did not accord with the schedule of reinforcement. Experiment I demonstrated that accurate instructions control discriminative performances on multiple avoidance schedules, and that such control persists in a novel discrimination. Experiments II and III showed that elimination of instruction-following occurs when inaccurate instructions cause subjects to contact a monetary loss contingency. Experiment IV demonstrated the reinforcing properties of accurate instructions. Skinner's view of rule-governed behavior is consistent with these findings, and can be extended to account for many aspects of instructional control of human operant behavior.     

Loss context enhances preferences for generosity but reduces preferences for honesty: Evidence from a combined behavioural-computational approach

The current literature has revealed mixed evidence on whether loss (vs. gain) context promotes or curtails human prosociality. The current study (N=96) aimed to address this issue by examining whether gain/loss context has distinct effects on different prosocial preferences combining computational modelling with Dictator Game and Message Game. These interactive games allow for dissociating preferences for generosity and honesty, which have been respectively associated with intuitive and deliberative systems. Our behavioural and computational modelling results indicate that loss context enhances concerns for generosity but reduces concerns for honesty. These findings support an account under the framework of dual process model asserting that loss facilitates intuitive responses during social decision-making, regardless of whether they are prosocial or proself. The current findings reconcile previous debates on the relationship between loss-gain context and human prosociality and shed light on the design of institutions to promote human prosocial behaviours.     

Gender differences in optimism,loss aversion and attitudes towards risk

Systematic differences in the attitudes of men and women towards risk is well established. In this paper, we investigate the joint role of two prominent psychological characteristics in explaining this difference. Our starting point is that risk assessments can be thought of, in general terms, to combine beliefs about the probability of negative outcomes occurring with a subjective valuation of how painful that negative outcome would be. Exploiting large-scale panel data from the United Kingdom, we find that gender differences in financial optimism and financial loss aversion – the stronger psychological response to monetary losses than monetary gains – explain a substantial proportion of the parallel gender difference in willingness to take risks. This result prevails even after controlling for the Big Five personality traits, suggesting that the prominent psychological characteristics capture different aspects of behaviour than the Big Five.     

社会价值取向与损失情境对不同时间压力下双人社会困境中合作行为的影响

为揭示双人社会困境中合作行为的影响因素,选取四种不同类型的双人社会困境,采用实验法考察社会价值取向与损失情境对不同时间压力下合作行为的影响。结果显示,亲社会个体的合作率显著高于亲自我个体的合作率,收益情境下的合作率显著高于损失情境下的合作率,在社会困境中双方冲突程度越大合作率越低;此外,高时间压力提升了亲自我个体在囚徒困境以及收益情境下信任困境中的合作率,同时降低了亲自我个体在损失情境下最大差异困境中的合作率。结果表明,社会价值取向、收益损失情境以及困境冲突程度均对合作行为的发生具有影响作用,而时间压力对合作行为的作用也同样受到三者的影响。这些发现能够为合作行为自动性的理论分歧提供新的证据。     

On the loss of information in conditional maximum likelihood estimation of item parameters

In item response models of the Rasch type (Fischer & Molenaar, 1995), item parameters are often estimated by the conditional maximum likelihood (CML) method. This paper addresses the loss of information in CML estimation by using the information concept of F-information (Liang, 1983). This concept makes it possible to specify the conditions for no loss of information and to define a quantification of information loss. For the dichotomous Rasch model, the derivations will be given in detail to show the use of the F-information concept for making comparisons for different estimation methods. It is shown that by using CML for item parameter estimation, some information is almost always lost. But compared to JML (joint maximum likelihood) as well as to MML (marginal maximum likelihood) the loss is very small. The reported efficiency in the use of information of CML to JML and to MML in several comparisons is always larger than 93%, and in tests with a length of 20 items or more, larger than 99%.     

Complicated grief following job loss: Risk factors for its development and maintenance

Increasing evidence shows that job loss can lead to symptoms of complicated grief (CG). However, little is known about which factors relate to the development and maintenance of CG symptoms following job loss. This study aimed to examine risk factors for the development and maintenance of job loss-related CG symptoms. For this study 485 Dutch workers who had lost their job were recruited (239 men and 246 women), with an average age of 50.2 years. A subsample of 128 participants also completed questionnaires at a six-month follow-up. We conducted correlational and multiple regression analyses (MRA) to examine the influence of the former work situation, coping strategies, and negative cognitions on job loss-related CG symptoms. MRA results showed that belief in an unjust world was related to job loss-related CG symptoms, cross-sectionally and longitudinally. Further, there was a significant relationship between CG symptoms following job loss and a preference for maladaptive coping over adaptive coping styles and a low level of self-esteem. This effect remained stable over time. These findings can inform the development of interventions for and early detection of job loss-related CG symptoms.     

Contextual framing of loss impacts harm avoidance during risky spatial decisions

Although the same decision to act can occur in multiple contexts, how these contexts differentially influence behavior is not well understood. In this paper, we investigate whether contextual framing affects individuals' behavior in spatial decision making. Although previous research suggests that individuals' judgments are sensitive to contextual (and particularly moral) factors of a scenario, no work has addressed whether this effect extends to spatial decisions. To investigate the impact of context on perceptual sensorimotor behavior, we superimposed two moral dilemmas (which we call help and harm) on a spatial decision-making paradigm. The basic task required participants select a target area while avoiding an overlapping nontarget area. Although the visuospatial task was constant, the moral context was changed when participants had to execute either a drone missile strike on enemies in the harm context or deliver ammunition to allies in the help context. Participants more strongly avoided losses in the harm context, reflected by a greater selection bias away from the nontarget (i.e., allies) on drone strike trials. These findings suggest that the contextual framing of a subjective perceived loss on a spatial decision can drive avoidant motor execution behavior.