The effects of varying fins in Müller-Lyer and Holding illusions

Summary Five experiments were conducted to determine how distortion of spatial position induced by unidirectional Müller-Lyer fins varied as a function of angle and length of fins. Research employing Cornsweet's staircase method yielded ambiguous results, but psychophysical methods of magnitude estimation, paired comparisons, and production showed conclusively that distortions of position are affected by angle and length of fins in a manner similar to that found in distortions of length. It was concluded that similar strategies are employed in processing attributes of length and position and that a theory based on averaging of attributes within an attentional field describes the performance of real observers.Experiments 1 and 2 were reported in a Master's thesis submitted by Nancy Smith to the University of Manitoba in 1987.     

Influences of Destructive Personality Information on Decision Making1

This study examined the effects of information about a landlord's personality on juror judgments for a landlord-tenant civil trial. The personality information manipulated was specifically relevant to destructive acts. Alternative versions of witness testimony were used to describe a landlord either high or low on need for power. treating people as objects, and negative life themes. This information strongly influenced aspects of the schema for this case constructed by the individual mock jurors. Destructive personality information caused dislike of the landlord and lowered the credibility of his story. If the landlord treated people as objects, the credibility of the tenant's story and positive evaluations of the tenant increased. Juror judgments about relative fault were strongly shifted by destructive personality information. An empirical model for juror decisions indicated a dynamic interplay of story components and fault judgments.     

Racial Attitudes and the Death Penalty1

This study investigated the relationship between overt and subtle forms of racism with Whites' recommendations for capital sentencing of Black and White offenders convicted of murder. White participants (n= 104) viewed 5 other “jurors” (all Whites or 4 Whites and 1 Black) on videotape individually presenting their decisions to vote for the death penalty in the case. It was hypothesized that the bias of high prejudice-scoring participants would be overt, but that the pattern for low prejudice-scoring participants would be more complex. As predicted, among high prejudice-scoring participants, Black defendants received stronger recommendations for the death penalty than did White defendants. Among low prejudice-scoring White participants, Black offenders received stronger recommendations for the death penalty only when a Black juror advocated the death penalty.     

Religion and the use of animals in research: some first thoughts

Religious traditions can be drawn on in a number of ways to illuminate discussions of the moral standing of animals and the ethical use of animals in scientific research. I begin with some general comments about relevant points in the history of major religions. I then briefly describe American civil religion, including the cult of health, and its relation to scientific research. Finally, I offer a critique of American civil religion from a Christian perspective.     

Lateralized Changes in Regional Cerebral Blood Flow during Performance of Verbal and Facial Recognition Tasks: Correlations with Performance and “Effort”

Functional neuroimaging has been used to investigate neural substrates of mnemonic processes, and cerebral blood flow (CBF) measures have been sensitive to activation with memory tasks. Studies of memory with two-dimensional¹³³Xenon clearance techniques found that word and face recognition tasks produced contralateral CBF changes in mid-temporal cortical regions. This study replicated the activation paradigm, expanding to the three-dimensional resolution of positron emission tomography (PET). Word and face recognition, and a control baseline task were administered to 19 healthy right-handed volunteers (11 men, 8 women) during successive 10 min PET¹⁵O-water measures of CBF. Quantitative CBF rates were calculated with the arterial input function and the equilibrium model. Redistributions of blood flow were compared across tasks using both absolute and relative (region/whole brain) CBF.Replicating the¹³³Xenon clearance findings, CBF was “appropriately” lateralized during task performance (left–right for words > left–right for faces) in the mid-temporal region. Contrary to predictions, the recognition tasks did not activate expected mesolimbic or prefrontal areas. The task-induced CBF changes also correlated with performance. Bilateral CBF in mid-temporal and parahippocampal gyrus regions of interest correlated with the ability to correctly identify word targets (sensitivity). Left-lateralized CBF in the amygdala and hippocampus correlated with better word sensitivity as well as specificity (ability to correctly reject foils). Complementally, right-lateralized CBF in the parahippocampal gyrus correlated with better face specificity performance. In addition, left-lateralized CBF in the amygdala and right-lateralized CBF in the parahippocampal gyrus and hippocampus correlated with “mental effort” indices (task performance relative to basal ability) for word and face memory tasks, respectively. Thus, whereas this recognition task showed the expected lateralized increase in the mid-temporal region and not in frontal and limbic areas, lateralized activation in some of these areas was associated with better performance. Exploratory analyses on other regions showed lateralized changes in one additional temporal region, the occipital-temporal, and several limbic regions.     

Extracting the coherent core of human probability judgement: a research program for cognitive psychology

Human intuition is a rich and useful guide to uncertain events in the environment but suffers from probabilistic incoherence in the technical sense. Developing methods for extracting a coherent body of judgement that is maximally consistent with a person's intuition is a challenging task for cognitive psychology, and also relevant to the construction of artificial expert systems. The present article motivates this problem, and outlines one approach to it.     

Jurors' Decisions in Trials of Battered Women Who Kill: The Role of Prior Beliefs and Expert Testimony1

The present research explored the influence of four factors on mock jurors' decisions in a homicide trial involving a battered woman who killed her abusive husband: (a) jurors' preexisting beliefs about wife abuse, (b) the presence of expert testimony on the battered woman syndrome, (c) jurors' beliefs in a just world, and (d) gender. Mock jurors listened to a trial involving a woman who had killed her abuser, which either contained expert testimony or did not, and then rendered various judgments about the case. Results indicated that those individuals who were more informed about the dynamics of abuse and those exposed to the expert testimony, compared to their respective counterparts, were more believing of the battered woman's account of what occurred. In general, weak believers in a just world were more lenient in their judgments, with verdicts of not guilty being associated with weaker beliefs in a just world than guilty verdicts. Weak believers in a just world also felt that the expert testimony applied more to the defendant than did strong believers. Finally, women who were weak believers in a just world were less likely to hold the defendant responsible for the events and to be more informed about the dynamics of abuse following the experiment.