The Model Human Processor and the older adult: parameter estimation and validation within a mobile phone task

The authors estimate weighted mean values for nine information processing parameters for older adults using the Card, Moran, and Newell (1983) Model Human Processor model. The authors validate a subset of these parameters by modeling two mobile phone tasks using two different phones and comparing model predictions to a sample of younger (N = 20; M-sub(age) = 20) and older (N = 20; M-sub(age) = 69) adults. Older adult models fit keystroke-level performance at the aggregate grain of analysis extremely well (R = 0.99) and produced equivalent fits to previously validated younger adult models. Critical path analyses highlighted points of poor design as a function of cognitive workload, hardware/software design, and user characteristics. The findings demonstrate that estimated older adult information processing parameters are valid for modeling purposes, can help designers understand age-related performance using existing interfaces, and may support the development of age-sensitive technologies.     

Rethinking neuroethics in the light of the extended mind thesis

The extended mind thesis is the claim that mental states extend beyond the skulls of the agents whose states they are. This seemingly obscure and bizarre claim has far-reaching implications for neuroethics, I argue. In the first half of this article, I sketch the extended mind thesis and defend it against criticisms. In the second half, I turn to its neuroethical implications. I argue that the extended mind thesis entails the falsity of the claim that interventions into the brain are especially problematic just because they are internal interventions, but that many objections to such interventions rely, at least in part, on this claim. Further, I argue that the thesis alters the focus of neuroethics, away from the question of whether we ought to allow interventions into the mind, and toward the question of which interventions we ought to allow and under what conditions. The extended mind thesis dramatically expands the scope of neuroethics: because interventions into the environment of agents can count as interventions into their minds, decisions concerning such interventions become questions for neuroethics.     

The role of the ‘other’ in national identity: exploring the context‐dependence of the national ingroup stereotype

Analysts from a range of disciplines (especially sociology and social anthropology) highlight the role of the ‘other’ in the construction and definition of national identity. Recently some social psychologists have come to emphasize the inherently relational nature of identity. Drawing upon these recent investigations, the present paper reports a field study investigating the context‐dependent nature of group identity. Using a modified version of the Katz–Braly task, British subjects (n=240) stereotyped two national groups: Americans and British. They did so in two conditions. In the ‘one‐group’ conditions, subjects rated either of the two groups. In the ‘two‐group’ conditions, they rated one whilst also considering the other. Following Oakes, Haslam and Turner (1994) we predicted that whereas subjects' stereotypes of the national outgroup (the Americans) would be unaffected by this manipulation, their stereotype of the national ingroup (the British) would be affected. This prediction was confirmed. We also predicted that the national ingroup stereotype obtained in the ‘two‐group’ condition would be one which was defined in contrast to the American ‘other’ which constituted the comparative context. Using a measure which takes into account the applicability of ingroup‐defining terms to both the ingroup and the outgroup (the diagnosticity measure of stereotyping proposed by McCauley and Stitt, 1978) we show that the ingroup identity definition produced in this condition did indeed differentiate the British from the Americans. The significance of these data for those concerned with the application of social psychological theory to real‐life social problems is discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Beliefs and data on the relationship between consistency and accuracy of eyewitness testimony

Two studies concerned with consistency and accuracy of eyewitness testimony were conducted. In Study 1 potential jurors indicated the degree to which they considered that various witness on‐stand behaviours indicated testimonial accuracy. Witness statements that were inconsistent with previous statements were considered to be the strongest indicators of inaccuracy. Study 2 examined the relationship between consistency and accuracy of testimony. Witnesses viewed a film of a robbery and were interviewed twice (2 weeks apart) about the crime in a 4 (interview format)×2 (interview occasion) design. Regardless of whether consistency was operationalised in terms of direct contradictions between interviews, or degree of agreement on detail across interviews, no more than 10% of the variance in overall accuracy rate was explained by any individual measure. Number of contradictions and overall agreement between interviews did, however, make additive contributions to prediction of overall accuracy. Also, higher correlations between contradiction‐based consistency measures and interview two accuracy rate were detected. Neither consistency nor accuracy for specific testimonial dimensions were predictive of accuracy on the other dimensions, or overall accuracy. Copyright © 1999 John Wiley & Sons, Ltd.     

The effects of explicit “Not Present” and “Don't Know” response options on identification decisions in computer-administered lineups

Eyewitness researchers recommend that “not present” and “don't know” response options should be presented with police lineups. Although it is important that witnesses—most of whom are unlikely to be familiar with the identification task—are fully cognizant of all response options available to them, an understanding of how explicit non-identification options affect performance is lacking. Across four experiments, including 3,633 participants and 8 different stimulus sets, we tested the effects of including non-identification options in computer-administered lineups. When explicit non-identification options were presented, target-present and -absent choosing decreased. This decrease in choosing was characterized by a shift from filler identifications to lineup rejections. ROC analyses revealed that there was no overall difference in discriminability between guilty and innocent suspects depending on response option condition. On balance, the findings suggest that, in addition to informing witnesses about acceptable responses, displaying non-identification response options does not undermine identification performance.     

Refining the blank line-up procedure: How should we instruct eyewitnesses?

Presenting a blank line-up—containing only fillers—to witnesses prior to showing a real line-up might be useful for screening out those who pick from the blank line-up as unreliable witnesses. We show that the effectiveness of this procedure varies depending on instructions given to witnesses. Participants (N = 462) viewed a simulated crime and attempted to identify the perpetrator from a line-up approximately 1 week later. Rejecting a blank line-up was associated with greater identification accuracy and greater diagnosticity of suspect identifications, but only when witnesses were instructed prior to the blank line-up that they would view a series of line-ups; the procedure was ineffective for screening when witnesses were advised they would view two line-ups or received no instruction. These results highlight the importance of instructions used in the blank line-up procedure, and the need for better understanding of how to interpret choosing patterns in this paradigm.     

Risk perceptions: assessment and relationship to influenza vaccination.

OBJECTIVE: Accurate measurement of beliefs about risk probability is essential to determine what role these beliefs have in health behavior. This study investigated the ability of several types of risk perception measures and of other constructs from health behavior theories to predict influenza vaccination. DESIGN: Prospective study in which students, faculty, and staff at 3 universities (N = 428) were interviewed in the fall, before influenza vaccine was available, and again early in the next calendar year. MAIN OUTCOME MEASURE: Self-reported influenza vaccination. RESULTS: Two interview questions that asked about feeling at risk and feeling vulnerable predicted subsequent behavior better (r = .44, p = .001) than 2 questions that asked for agreement or disagreement with statements about risk probability (r = .25, p = .001) or 4 questions that asked respondents to estimate the magnitude of the risk probability (r = .30, p = .001). Of the 4 perceived risk magnitude scales, a 7-point verbal scale was the best predictor of behavior. Anticipated regret was the strongest predictor of vaccination (r = .45, p = .001) of all constructs studied, including risk perceptions, worry, and perceived vaccine effectiveness. CONCLUSION: Risk perceptions predicted subsequent vaccination. However, perceived risk phrased in terms of feelings rather than as a purely cognitive probability judgment predicted better. Because neither feeling at risk nor anticipated regret is represented in the most commonly used theories of health behavior, the data suggest that these theories are missing important constructs.