Ageing affects conceptual but not perceptual memory processes

Whereas age effects commonly occur in tests of explicit memory, tests of implicit memory often show age invariance. In two experiments, the traditional confound between test type (implicit vs explicit) and retrieval process (conceptually driven vs perceptually driven) was removed by using conceptually driven and perceptually driven tests of both implicit and explicit memory. Experiment 1 revealed a significant age effect for conceptually driven retrieval and no age effect for perceptually driven retrieval, regardless of the type of memory being measured. Experiment 2 highlighted a difference between the two age groups in their ability to utilise semantic encoding in a nominally perceptually driven explicit memory test. The paper concludes that although perceptually driven processing is stable over age, particular care must be taken to minimise contamination from conceptually driven retrieval processes in such investigations.     

Attention alters the appearance of motion coherence

Selective attention enhances visual information processing, as measured by behavioral performance and neural activity. However, little is known about its effects on subjective experience. Here, we investigated the effect of transient (exogenous) attention on the appearance of visual motion, using a psychophysical procedure that directly measures appearance and controls for response bias. Observers viewed pairs of moving dot patterns and reported the motion direction of the more coherent pattern. Directing attention (via a peripheral precue) to a stimulus location increased its perceived coherence level and improved performance on a direction discrimination task. In a control experiment, we ruled out response bias by lengthening the time interval between the cue and the stimuli, so that the effect of transient attention could no longer be exerted. Our results are consistent with those of neurophysiological studies showing that attention modulates motion processing and provide evidence of a subjective perceptual correlate of attention, with a concomitant effect on performance.     

Death and organ procurement: public beliefs and attitudes

Although "brain death" and the dead donor rule--i.e., patients must not be killed by organ retrieval--have been clinically and legally accepted in the U.S. as prerequisites to organ removal, there is little data about public attitudes and beliefs concerning these matters. To examine the public attitudes and beliefs about the determination of death and its relationship to organ transplantation, 1351 Ohio residents >18 years were randomly selected and surveyed using random digit dialing (RDD) sample frames. The RDD telephone survey was conducted using computer-assisted telephone interviews. The survey instrument was developed from information provided by 12 focus groups and a pilot study of the questionnaire. Three scenarios based on hypothetical patients were presented: "brain dead," in a coma, or in a persistent vegetative state (PVS). Respondents provided personal assessments of whether the patient in each scenario was dead and their willingness to donate that patient's organs in these circumstances. More than 98 percent of respondents had heard of the term "brain death," but only one-third (33.7%) believed that someone who was "brain dead" was legally dead. The majority of respondents (86.2%) identified the "brain dead" patient in the first scenario as dead, 57.2 percent identified the patient in a coma as dead (Scenario 2), and 34.1 percent identified the patient in a PVS as dead (Scenario 3). Nearly one-third (33.5%) were willing to donate the organs of patients they classified as alive for at least one scenario, in seeming violation of the dead donor rule. Most respondents were not willing to violate the dead donor rule, although a substantial minority was. However, the majority of respondents were unaware, misinformed, or held beliefs there were not congruent with current definitions of "brain death." This study highlights the need for more public dialogue and education about "brain death" and organ donation.     

Abolishing the word-length effect

The authors report 2 experiments that compare the recall of long and short words in pure and mixed lists. In pure lists, long words were much more poorly remembered than short words. In mixed lists, this word-length effect was abolished and both the long and short words were recalled as well as short words in pure lists. These findings contradict current models that seek to explain the word-length effect in terms of item-based effects such as difficulty in assembling items, or in terms of list-based accounts of rehearsal speed. An alternative explanation, drawing on ideas of item complexity and item distinctiveness, is proposed.