English letter frequencies and their applications: part I

This article presents data regarding the relative frequencies of single letters in English, organized by word length and letter position. Derived from a parsimonious sample of English word use patterns presented by Whissell in 1998, the data accurately represent letter frequencies found in modern English. These data provide a resource for various applications, including reading research and practice.     

The sampling distributions of Gaussian ROC statistics

For a discrimination experiment, a plot of the hit rate against the false-alarm rate--the ROC curve--summarizes performance across a range of confidence levels. In many content areas, ROCs are well described by a normal-distribution model and the z-transformed hit and false-alarm rates are approximately linearly related. We examined the sampling distributions of three parameters of this model when applied to a ratings procedure: the area under the ROC (Az), the normalized difference between the means of the underlying signal and noise distributions (da), and the slope of the ROC on z-coordinates (s). Statistical bias (the degree to which the mean of the sampling distribution differed from the true value) was trivial for Az, small but noticeable for da, and substantial for s. Variability of the sampling distributions decreased with the number of trials and was also affected by the number of response categories available to the participant and by the overall sensitivity level. Figures in the article and tables available on line can be used to construct confidence intervals around ROC statistics and to test statistical hypotheses.     

Sum-difference theory of remembering and knowing: a two-dimensional signal-detection model

In the remember-know paradigm for studying recognition memory, participants distinguish items whose presentations are episodically remembered from those that are merely familiar. A one-dimensional model postulates that remember responses are just high-confidence old judgments, but a meta-analysis of 373 experiments shows that the receiver operating characteristic (ROC) curves predicted by this model have the wrong slope. According to the new sum-difference Theory of remembering and knowing (STREAK), old items differ from new ones in both global and specific memory strength: The old-new judgment is based on a weighted sum of these dimensions, and the remember- know judgment is based on a weighted difference. STREAK accounts for the form of several novel kinds of ROC curves and for existing remember-know and item-recognition data.     

Connecting Past with Present: A Mixed-Methods Science Ethics Course and its Evaluation

We present a graduate science ethics course that connects cases from the historical record to present realities and practices in the areas of social responsibility, authorship, and human/animal experimentation. This content is delivered with mixed methods, including films, debates, blogging, and practicum; even the instructional team is mixed, including a historian of science and a research scientist. What really unites all of the course’s components is the experiential aspect: from acting in historical debates to participating in the current scientific enterprise. The course aims to change the students’ culture into one deeply devoted to the science ethics cause. To measure the sought after cultural change, we developed and validated a relevant questionnaire. Results of this questionnaire from students who took the course, demonstrate that the course had the intended effect on them. Furthermore, results of this questionnaire from controls indicate the need for cultural change in that cohort. All these quantitative results are reinforced by qualitative outcomes.     

Watching the birdie watching you: eyewitness memory for actions using CCTV recordings of actual crimes

In this paper we describe a method of assessing eyewitness performance for actual crimes that could prove a valuable addition to more traditional experimental and field‐based approaches to the study of eyewitnessing. We present the findings of the first reported attempt to assess the accuracy of information contained in police statements given by eyewitnesses to actual criminal episodes using CCTV as a means of verification. Employing the criterion of using only those items that could be verified against CCTV recordings (largely action details), both victims and bystanders from eight incidents of assault were found to be highly accurate in their accounts (96% accurate). These results are discussed in terms of what they might indicate about the relationship between arousal and eyewitness performance and how they compare with laboratory and other field‐based approaches to the study of eyewitness memory. In addition, we consider some of the methodological, technological and practical constraints associated with this novel approach and its possible future applications to the study of everyday memory as well as memory for unusual events. Copyright © 2001 John Wiley & Sons, Ltd.     

Predicting future reconviction in offenders with intellectual disabilities: the predictive efficacy of VRAG, PCL-SV, and the HCR-20

Accurate predictions of future reconviction, including those for violent crimes, have been shown to be greatly aided by the use of formal risk assessment instruments. However, it is unclear as to whether these instruments would also be predictive in a sample of offenders with intellectual disabilities. In this study, the authors have shown that the Violence Risk Appraisal Guide (V. L. Quinsey, G. T. Harris, M. E. Rice, & C. Cormier, 1998); the Psychopathy Checklist--Screening Version (S. D. Hart, D. N. Cox, & R. D. Hare, 1995); and the History, Clinical, Risk Management--20 (C. D. Webster, K. S. Douglas, D. Eaves, & S. D. Hart, 1997) were all significant predictors of violent and general reconviction in this sample, and in many cases, their efficacy was greater than in a control sample of mentally disordered offenders without an intellectual disability.