Age,executive function,and social decision making: a dorsolateral prefrontal theory of cognitive aging

Current neuropsychological models propose that some age-related cognitive changes are due to frontal-lobe deterioration. However, these models have not considered the possible subdivision of the frontal lobes into the dorsolateral and ventromedial regions. This study assessed the age effects on 3 tasks of executive function and working memory, tasks dependent on dorsolateral prefrontal dysfunction; and 3 tasks of emotion and social decision making, tasks dependent on ventromedial prefrontal dysfunction. Age-related differences in performance were found on all tasks dependent on dorsolateral prefrontal dysfunction. In contrast, age-related differences were not found on the majority of the tasks dependent on ventromedial prefrontal dysfunction. The results support a specific dorsolateral prefrontal theory of cognitive changes with age, rather than a global decline in frontal-lobe function.     

On euthanasia: blindspots in the argument from mercy

In the euthanasia debate, the argument from mercy holds that if someone is in unbearable pain and is hopelessly ill or injured, then mercy dictates that inflicting death may be morally justified. One common way of setting the stage for the argument from mercy is to draw parallels between human and animal suffering, and to suggest that insofar as we are prepared to relieve an animal's suffering by putting it out of its misery we should likewise be prepared to offer the same relief to human beings.
In this paper, I will argue that the use of parallels between human and animal suffering in the argument from mercy relies upon truncated views of how the concept of a human being enters our moral thought and responsiveness. In particular, the focus on the nature and extent of the empirical similarities between human beings and animals obscures the significance for our moral lives of the kind of human fellowship which is not reducible to the shared possession of empirical capacities.
I will suggest that although a critical examination of the blindspots in these arguments does not license the conclusion that euthanasia for mercy's sake is never morally permissible, it does limit the power of arguments such as those provided by Rachels and Singer to justify it. I will further suggest that examination of these blindspots helps to deepen our understanding of what is at stake in the question of euthanasia in ways that tend otherwise to remain obscured.     

Source monitoring in a generative task

Following exposure to experimenter-provided examples of space creatures, people tend to conform to the features contained in the examples when creating their own novel space creatures. In three experiments, we manipulated factors known to affect source-monitoring accuracy to determine how these manipulations would influence conformity to experimenter-provided examples. In Experiment 1 we altered people's cognitive agenda by means of the instructions given before the drawing task. In Experiment 2 we examined how time pressure would affect the level of conformity, and in Experiment 3 we manipulated the availability of the creatures during the drawing task by making them available to half the participants. Conformity decreased when extended source-monitoring processes were engaged and increased when these processes were disrupted. The results from the three experiments were consistent with the principles of the source-monitoring framework.     

Behavioral and electrical brain measures of semantic priming in patients with Alzheimer's disease: implications for access failure versus deterioration hypotheses

This study investigated the nature of anomia and semantic memory deficits in patients with Alzheimer's disease (DAT). We measured reaction time (RT) and the N400 event-related brain potential (ERP) in a word-picture semantic priming paradigm for DAT patients and elderly controls. For patients, pictures were classified as a function of the individual's naming ability to determine whether naming deficits reflected a failure to access a picture's name or reflected a deterioration of its semantic representation. As expected, DAT patients had significantly poorer naming performance than controls. For successfully named pictures, robust RT and ERP priming effects were obtained in both groups. In DAT patients, priming for unnamed pictures was heterogeneous. The results are discussed in terms of current hypotheses of semantic memory deficits in DAT.     

Intimate partner stalking and femicide: urgent implications for women's safety

This study describes the type and extent of intimate partner stalking and threatening behaviors that occurred within 12 months prior to a major assault or attempted or actual partner femicide and specifies which behaviors were associated with an increased risk of potential or actual lethality.The design was a ten-city case-control study of 821 women: 384 abuse victims and 437 attempted or actual femicide informants. Data were derived using a 16-item inventory. Logistic regressions, with adjustments for demographic variables, were used to identify the significant perpetrator behaviors associated with attempted/actual femicide.Women who reported the perpetrator followed or spied on them were more than twice as likely t o become attempted/actual femicide victims. Threats by the perpetrator to harm the children if the woman left or did not return to the relationship place the woman at a ninefold increase in the risk of attempted/actual femicide. Conclusions are that certain stalking and threatening behaviors are strong risk factors for lethality, and women must be so advised.     

Varieties of preschool hyperactivity: multiple pathways from risk to disorder

In this paper we examine the characteristics of preschool attention deficit hyperactivity disorder (ADHD) from both mental disorder and developmental psychopathology points of view. The equivalence of preschool and school-aged hyperactivity as a behavioral dimension is highlighted together with the potential value of extending the use of the ADHD diagnostic category to the preschool period where these behaviours take an extreme and impairing form (assuming age appropriate diagnostic items and thresholds can be developed). At the same time, the importance of identifying pathways between risk and later ADHD is emphasized. Developmental discontinuity and heterogeneity are identified as major characteristics of these pathways. We argue that models that distinguish among different developmental types of early-emerging problems are needed. An illustrative taxonomy of four developmental pathways implicating preschool hyperactivity is presented to provide a framework for future research.     

Analog number representations in mongoose lemurs (Eulemur mongoz): evidence from a search task

A wealth of data demonstrating that monkeys and apes represent number have been interpreted as suggesting that sensitivity to number emerged early in primate evolution, if not before. Here we examine the numerical capacities of the mongoose lemur (Eulemur mongoz), a member of the prosimian suborder of primates that split from the common ancestor of monkeys, apes and humans approximately 47–54 million years ago. Subjects observed as an experimenter sequentially placed grapes into an opaque bucket. On half of the trials the experimenter placed a subset of the grapes into a false bottom such that they were inaccessible to the lemur. The critical question was whether lemurs would spend more time searching the bucket when food should have remained in the bucket, compared to when they had retrieved all of the food. We found that the amount of time lemurs spent searching was indicative of whether grapes should have remained in the bucket, and furthermore that lemur search time reliably differentiated numerosities that differed by a 1:2 ratio, but not those that differed by a 2:3 or 3:4 ratio. Finally, two control conditions determined that lemurs represented the number of food items, and neither the odor of the grapes, nor the amount of grape (e.g., area) in the bucket. These results suggest that mongoose lemurs have numerical representations that are modulated by Webers Law.