How research ethics boards are undermining survey research on Canadian university students

In Canada, all research conducted by individuals associated with universities must be subjected to review by research ethics boards (REB). Unfortunately, decisions reached by REBs may seriously compromise the integrity of university-based research. In this paper attention will focus on how requirements of REBs and a legal department in four Canadian universities affected response rates to a survey of domestic and international students. It will be shown that in universities in which students were sent a legalistic cover letter to a mail survey, or were required to sign a consent form, lower response rates were achieved than in universities in which students were sent a relatively friendly letter. In turn, lower response rates resulted in: sample characteristics that deviated from population characteristics; a reduction in the possibility of testing research hypotheses; and increased survey costs. As a consequence, it is argued that the unreasonable demands of REBs are seriously compromising the quality of research that can be carried out on Canadian university students.     

Risk Reduction Behaviors and Provider Communication Following Genetic Counseling and BRCA1 Mutation Testing in an African American Kindred

Little is known about the impact of cancer genetic counseling and testing on health behaviors in racial and ethnic subgroups. This prospective observational study examined use of risk reduction strategies following BRCA1 counseling and testing. Participants were female members of an African American kindred who received genetic education, counseling and testing (n = 40) and completed a 1-year follow-up interview. Mutation carriers were more likely to opt for breast (100%, 7/7) and ovarian (25%; 1 of 4) cancer surveillance than prophylactic surgery. Following genetic counseling, 71% (5/7) of the BRCA1 carriers who opted for surveillance reported having a mammogram within the year following receipt of their genetic test results. Ovarian cancer screening among mutation carriers increased from 0% at baseline to 25% (one of four) at 1 year. Compared to noncarriers (23%, 7/30), carriers (70%, 7/10) were more likely to discuss their BRCA1 test results with their primary health care providers. Surveillance for breast cancer was preferred to prophylactic surgery and chemoprevention as a way to reduce risk for these cancers. Our data indicate that patient-provider communication about BRCA1 test results is suboptimal.     

An analysis of reinforcement history effects

Four pigeons were exposed to two tandem variable-interval differential-reinforcement-of-low-rate schedules under different stimulus conditions. The values of the tandem schedules were adjusted so that reinforcement rates in one stimulus condition were higher than those in the other, even though response rates in the two conditions were nearly identical. Following this, a fixed-interval schedule of either shorter or longer values than, or equal to the baseline schedule, was introduced in the two stimulus conditions respectively. Response rates during those fixed-interval schedules typically were higher in the presence of the stimuli previously correlated with the lower reinforcement rates than were those in the presence of the stimuli previously correlated with the higher reinforcement rates. Such effects of the reinforcement history were most prominent when the value of the fixed-interval schedule was shorter. The results are consistent with both incentive contrast and response strength conceptualizations of related effects. They also suggest methods for disentangling the effects of reinforcement rate on subsequent responding, from the response rate with which it is confounded in many conventional schedules of reinforcement.     

Toward a unified theory of decision criterion learning in perceptual categorization

Optimal decision criterion placement maximizes expected reward and requires sensitivity to the category base rates (prior probabilities) and payoffs (costs and benefits of incorrect and correct responding). When base rates are unequal, human decision criterion is nearly optimal, but when payoffs are unequal, suboptimal decision criterion placement is observed, even when the optimal decision criterion is identical in both cases. A series of studies are reviewed that examine the generality of this finding, and a unified theory of decision criterion learning is described (Maddox & Dodd, 2001). The theory assumes that two critical mechanisms operate in decision criterion learning. One mechanism involves competition between reward and accuracy maximization: The observer attempts to maximize reward, as instructed, but also places some importance on accuracy maximization. The second mechanism involves a flat-maxima hypothesis that assumes that the observer's estimate of the reward-maximizing decision criterion is determined from the steepness of the objective reward function that relates expected reward to decision criterion placement. Experiments used to develop and test the theory require each observer to complete a large number of trials and to participate in all conditions of the experiment. This provides maximal control over the reinforcement history of the observer and allows a focus on individual behavioral profiles. The theory is applied to decision criterion learning problems that examine category discriminability, payoff matrix multiplication and addition effects, the optimal classifier's independence assumption, and different types of trial-by-trial feedback. In every case the theory provides a good account of the data, and, most important, provides useful insights into the psychological processes involved in decision criterion learning.     

Uptake of BRCA1 Genetic Testing in Adult Sisters and Daughters of Known Mutation Carriers in Norway

This study was undertaken to examine transmission of information to first-degree relatives of BRCA1 mutation carriers and uptake of genetic testing. The intention was to consider revision of current legislation related to privacy if information on life-saving health care was not disseminated to at-risk family members. The Norwegian Radium Hospital provides clinical genetics services for families at high risk for hereditary breast and ovarian cancer. Together with major hospitals nationwide we provide medical surveillance. Nearly all expenses are covered by the National Health insurance. Because of the high number of families with founder mutations in BRCA1, we are in a unique position to gather information about these groups. Within a consecutive series, we identified 75 BRCA1 mutation carriers and registered information transmission and uptake of genetic testing 6 months or more after the index mutation carriers had been informed about their mutation status. These 75 BRCA1 mutation carriers had 172 living first-degree relatives, aged 18 years or older (84 females, 88 males). Forty-four out of 54 (81.5%) of females over 30 had opted for genetic testing. The testing rate among all relatives was 43%. At any age, 63% of the females underwent genetic testing compared with 24% of the males (p<0.05). The overwhelming majority of adult females at risk opted for genetic testing. Males with daughters more frequently than males without daughters asked for testing. The findings give neither reason to reconsider legislation on privacy, nor for us to consider more aggressive methods of contacting relatives.     

Bayesian modeling of measurement error in predictor variables using item response theory

It is shown that measurement error in predictor variables can be modeled using item response theory (IRT). The predictor variables, that may be defined at any level of an hierarchical regression model, are treated as latent variables. The normal ogive model is used to describe the relation between the latent variables and dichotomous observed variables, which may be responses to tests or questionnaires. It will be shown that the multilevel model with measurement error in the observed predictor variables can be estimated in a Bayesian framework using Gibbs sampling. In this article, handling measurement error via the normal ogive model is compared with alternative approaches using the classical true score model. Examples using real data are given.This paper is part of the dissertation by Fox (2001) that won the 2002 Psychometric Society Dissertation Award.     

失恋经历对爱情相关刺激注意偏向的影响:趋近还是回避?

为探讨失恋经历对爱情相关刺激注意偏向的影响,采用眼动和事件相关电位技术考察有、无失恋个体在加工积极和消极爱情信息时眼动和ERP特征。通过2个实验结果发现：在总注视时间和注视点个数眼动指标上,图片类型和失恋经历的交互作用达到统计显著水平;有失恋经历被试比无失恋经历被试对消极爱情图片的注视点更多,注视时间更长。积极爱情图片比消极爱情图片诱发的N1波峰更大,有失恋经历被试对积极图片的N1潜伏期显著快于无失恋经历的被试;有失恋经历被试在积极爱情图片上的P1波峰小于无失恋经历被试。研究表明,有、无失恋经历被试对爱情相关刺激的注意偏向存在眼动特征和神经生理上的显著差异：有失恋经历者在行为上对消极爱情图片存在注意趋近偏向,而在神经生理上对积极爱情图片存在注意回避倾向。     

Effects consistent with behavioral contrast during a multiple schedule for discrimination training on mands for attention

This study used a multiple schedule to assess the effects of an S+ or S- in the absence of rules on excessive mand rates with three school-aged children with disabilities and assessed possible contrast effects occurring in conjunction with the intervention. Each of the three participants was exposed to the presence or absence of an S- (black baseball cap). When it was worn, mand approach rates decreased for all three participants; conversely, mand rates increased to twice the baseline rates when the experimenter was not wearing the black baseball cap. Generalization probes conducted for one of the three caregivers showed similar changes when the caregiver wore the cap. Results suggest that effects consistent with positive behavioral contrast occurred with all participants.     

Is the heart preadapted to hypoxia? Evidence from fractal dynamics of heartbeat interval fluctuations at high altitude (5,050 m)

The dynamics of heartbeat interval time series over large time scales were studied by a modifed random walk analysis introduced recently asDetrended Fluctuation Analysis. In this analysis, the intrinsic fractal long-range power-law correlation properties of beat-to-beat fluctuations generated by the dynamical system (i.e., cardiac rhythm generator), after decomposition from extrinsic uncorrelated sources, can be quantified by the scaling exponent (α) which, in healthy subjects, for time scales of ∼10⁴ beats is ∼1.0. The effects of chronic hypoxia were determined from serial heartbeat interval time series of digitized twenty-four-hour ambulatory ECGs recorded in nine healthy subjects (mean age thirty-four years old) at sea level and during a sojourn at 5,050 m for thirty-four days (Ev-K2-CNR Pyramid Laboratory, Sagarmatha National Park, Nepal). The group averaged α exponent (±SD) was 0.99±0.04 (range 0.93–1.04). Longitudinal assessment of α in individual subjects did not reveal any effect of exposure to chronic high altitude hypoxia. The finding of α∼1 indicating scale-invariant long-range power-law correlations (1/f noise) of heartbeat fluctuations would reflect a genuinely self-similar fractal process that typically generates fluctuations on a wide range of time scales. Lack of a characteristic time scale along with the absence of any effect from exposure to chronic hypoxia on scaling properties suggests that the neuroautonomic cardiac control system is preadapted to hypoxia which helps prevent excessive mode-locking (error tolerance) that would restrict its functional responsiveness (plasticity) to hypoxic or other physiological stimuli. Editorial Note: A philosopher is, by definition, a lover of wisdom. In the following article, Dr. Dimitrov, as a philosopher, examines the principles that underlie being and thinking as performed by the structures of the brain. He reports his thoughts in a “virtual context.” Virtual, a word enjoying great popularity today, is derived from the Latin word for man; it describes manliness and implies apparent, but not actual, power. In his analysis of how information is dealt with by the human being, the author uses theoretical physics and mathematics that may seem arcane to some readers. A major aspect of his thesis declares that the effective performance of information systems relies not on the structures involved, but on the way they interact.