Empirical underidentification in estimating random utility models: The role of choice sets and standardizations

A standard approach to distinguishing people’s risk preferences is to estimate a random utility model using a power utility function to characterize the preferences and a logit function to capture choice consistency. We demonstrate that with often-used choice situations, this model suffers from empirical underidentification, meaning that parameters cannot be estimated precisely. With simulations of estimation accuracy and Kullback–Leibler divergence measures we examined factors that potentially mitigate this problem. First, using a choice set that guarantees a switch in the utility order between two risky gambles in the range of plausible values leads to higher estimation accuracy than randomly created choice sets or the purpose-built choice sets common in the literature. Second, parameter estimates are regularly correlated, which contributes to empirical underidentification. Examining standardizations of the utility scale, we show that they mitigate this correlation and additionally improve the estimation accuracy for choice consistency. Yet, they can have detrimental effects on the estimation accuracy of risk preference. Finally, we also show how repeated versus distinct choice sets and an increase in observations affect estimation accuracy. Together, these results should help researchers make informed design choices to estimate parameters in the random utility model more precisely.     

The sibling familiarity effect: Is within-person facial variability shared across siblings?

Humans are experts at familiar face recognition, but poor at unfamiliar face recognition. Familiarity is created when a face is encountered across varied conditions, but the way in which a person’s appearance varies is identity-specific, so familiarity with one identity does not benefit recognition of other individuals. However, the faces of biological siblings share structural similarities, so we explored whether the benefits of familiarity are shared across siblings. Results show that familiarity with one half of a sibling pair improves kin detection (experiment 1), and that unfamiliar face matching is more accurate when targets are the siblings of familiar versus unfamiliar individuals (experiment 2). PCA applied to facial images of celebrities and their siblings demonstrates that faces are generally better reconstructed in the principal components of a same-sex sibling than those of an unrelated individual. When we encounter the unfamiliar sibling of someone we already know, our pre-existing representation of their familiar relation may usefully inform processing of the unfamiliar face. This can benefit both kin detection and identity processing, but the benefits are constrained by the degree to which facial variability is shared.     

幽门螺杆菌感染的检测

幽门螺杆菌感染的诊断方法,按检测原理不同可分为形态学检查、细菌培养、尿素酶依赖性试验、血清免疫学、基因分子生物学检测五大类。而按照检测创伤性的不同可分为侵入和非侵入检查两类。本文将对这些方法分类介绍评价。     

EFFECTS OF POINT‐LOSS PUNISHERS ON HUMAN SIGNAL‐DETECTION PERFORMANCE

Three experiments using human participants varied the distribution of point‐gain reinforcers or point‐loss punishers in two‐alternative signal‐detection procedures. Experiment 1 varied the distribution of point‐gain reinforcers for correct responses (Group A) and point‐loss punishers for errors (Group B) across conditions. Response bias varied systematically as a function of the relative reinforcer or punisher frequencies. Experiment 2 arranged two conditions — one where an unequal ratio of reinforcement (5:1 or 1:5) was presented without punishment (R‐only), and another where the same reinforcer ratio was presented with an equal distribution of point‐loss punishers (R+P). Response bias was significantly greater in the R‐only condition than the R+P condition, supporting a subtractive model of punishment. Experiment 3 varied the distribution of point‐gain reinforcers for correct responses across four unequal reinforcer ratios (5:1, 2:1, 1:2, 1:5) both without (R‐only) and with (R+P) an equal distribution of point‐loss punishers for errors. Response bias varied systematically with changes in relative reinforcer frequency for both R‐only and R+P conditions, with 5 out of 8 participants showing increases in sensitivity estimates from R‐only to R+P conditions. Overall, the results indicated that punishers have similar but opposite effects to reinforcers in detection procedures and that combined reinforcer and punisher effects might be better modeled by a subtractive punishment model than an additive punishment model, consistent with research using concurrent‐schedule choice procedures.     

Bobwhite quail (Colinus virginianus) hatchlings track the direction of human gaze

Gaze following allows individuals to detect the locus of attention of both conspecifics and other species. However, little is known about how this ability develops. We explored the emergence of bobwhite quail hatchlings’ ability to track human gaze by assessing their avoidance behavior in an open arena under five testing conditions: (1) a Direct Gaze condition, in which an experimenter looking down was positioned above one of two approach areas; (2) a Gaze Follow condition in which an experimenter, positioned equidistant between two approach areas, directed his/her gaze towards one of the areas; (3) a Masked Gaze Follow condition, in which the experimenter wore a mask during the Gaze Follow test; (4) a Deprived Face Experience condition, in which hatchlings were deprived of experience with human faces prior to the Gaze Follow test; and (5) a Control condition in which no experimenter was present during testing. Results revealed that hatchlings from the Direct Gaze condition preferred the non-gazed approach area at all ages tested. Hatchlings from the Gaze Follow condition preferred the non-gazed approach area at 48 and 72 h, but not at 24 h of age. In contrast, hatchlings from the Masked Gaze Follow, Deprived Face and Control conditions did not prefer either approach area at any age tested. These results indicate that experience with human faces plays a key role in the rapid emergence of gaze following behavior in bobwhite quail hatchlings.     

不同结构文章重复阅读时主题转换效应的眼动研究

选取36名大学生,运用眼动技术,探讨不同结构类型文章在重复阅读时主题转换效应的变化特点。被试阅读的材料有两类:一是段落内部各个句子之间为平行关系(平行材料);一是每段第一个句子为该段落主题句(总分材料)。结果发现,两类材料在第一遍阅读过程中均出现了显著的主题转换效应,但在重复阅读时,主题转换效应消失,说明读者在第一遍阅读时已构建了文章的主题结构表征,并以此来指导后面的阅读。该结果支持共同策略假设理论,说明无论文章中是否存在标记,读者在阅读时都会构建一定完善的主题结构表征。     

高中二年级学生双字词阅读知觉广度的眼动研究

采用“呈现随眼动变化技术”对12名高中二年级学生的双字词阅读知觉广度进行了眼动研究。结果发现：（1）高中二年级学生的双字词阅读知觉广度具有不对称性。（2）高中二年级学生的双字词阅读知觉广度为注视点左侧一个双字词到右侧两个双字词的空间。     

高、低强迫症状个体的词语再认差异

比较了高强迫症状（High obsessive compulsive symptom, HOC）和低强迫症状（Low obsessive compulsive symptom, LOC）被试对于不同类型词语（强迫症敏感词、情绪词和中性词）再认成绩和记忆信心的差异。结果发现,HOC组记忆保存量显著低于LOC组（p<0.05）,表明HOC组对强迫症敏感词存在一定的偏好;通过对被试反应信心的检测和信号侦察论的应用,发现HOC组对中性词再认正误的判断觉察能力（d’值）低于LOC组（边缘显著：p＝0.054）;在正确反应信心上,被试类型和词语类型间存在交互作用,F(1,22)=4.60,p<0.05。本研究认为HOC组辨别能力的缺损可能导致其记忆信心方面的降低,这种假设还需要进一步的认知和脑功能研究来证实。     

精细阐述与先行信息激活水平的动态变化

该研究运用窗口阅读及命名探测技术,对即时与延迟状态下合适与不合适背景信息的激活模式进行了探讨。被试阅读含有精细阐述错误信息的语篇,并对合适或不合适的探测词进行命名反应。结果发现,虽然即时条件下,受精细阐述的不合适探测词激活水平高于合适探测词,但当延迟时间为1500ms时,原有的激活模式发生了逆转。这种激活模式的变化主要是由于合适的背景信息随时程延长激活水平得到提升所致。     

The Relationship Between Religious Coping Style and Anxiety over Breast Cancer in African American Women

In this study, we investigated the relationship between religious coping style and anxiety related to breast cancer and the use of mammography in a sample of African American women. We also assessed the relationship of breast cancer anxiety to related variables such as church affiliation and attendance, church teachings on health, and acceptance of those teachings.