Effects of divided attention and word concreteness on correct recall and false memory reports

Lists of thematically related words were presented to participants with or without a concurrent task. In Experiments 1 and 2, respectively, English or Spanish word lists were either low or high in concreteness (concrete vs abstract words) and were presented, respectively, auditorily or visually for study. The addition of a concurrent visual or auditory task, respectively, substantially reduced correct recall and doubled the frequency of false memory reports (nonstudied critical or theme words). Divided attention was interpreted as having reduced the opportunity for participants to monitor successfully their elicitations of critical associates. Comparisons of concrete and abstract lists revealed significantly more recalls of false memories for abstract than concrete word lists. Comparisons between two levels of attention, two levels of word concreteness, and two presentation modalities failed to support the "more is less" effect by which enhanced correct recall is accompanied by increased frequencies of false memories.     

Animal spare parts? A Canadian public consultation on xenotransplantation

Xenotransplantation, or the use of animal cells, tissues and organs for humans, has been promoted as an important solution to the worldwide shortage of organs. While scientific studies continue to be done to address problems of rejection and the possibility of animal-to-human virus transfer, socio-ethical and legal questions have also been raised around informed consent, life-long monitoring, animal welfare and animal rights, and appropriate regulatory practices. Many calls have also been made to consult publics before policy decisions are made. This paper describes the Canadian public consultation process on xenotransplantation carried out by the Canadian Public Health Association in an arm’s length process from Health Canada, the ministry overseeing government health policy and regulation. Focusing on six citizen fora conducted around the country patterned after the citizen jury deliberative approach, the paper describes the citizen panelists’ recommendations to hold off on proceeding with clinical trials and the rationales behind this recommendation. The consultation process is discussed in the context of constructive technology assessment, a framework which argues for broader input into earlier stages of technology innovation, particularly at the technology design stage. This study was supported by a grant to the first author from the Social Sciences and Humanities Research Council in Canada.     

Straightness as a cue for luminance edge interpretation

In order to determine the reflectance of a surface, it is necessary to discount luminance changes produced by illumination variation, a process that requires the visual system to respond differently to luminance changes that are due to illumination and reflectance. It is known that various cues can be used in this process. By measuring the strength of lightness illusions, we find evidence that straightness is, used as a cue: When a boundary is straight rather than curved, it has a greater tendency to be discounted, as if it were an illumination edge. The strongest illusions occur when a boundary has high contrast and has multiple X-junctions that preserve a consistent contrast ratio.     

Comparing performance by parents and offspring on a rapid tapping task

The purpose of this study was to identify the relationships between 42 parents' and their offsprings' performance on a rapid tapping task. It was expected that genetic predispositions would gradually limit children's performance on a tapping task as they matured chronologically. Four different age groups of children and their parents performed the tapping task on different sizes of boards. Repeated-measures analysis of variance indicated that, while parents' mean performance was generally higher than that of their children (F = 32.89, p < .001), the difference was affected by the children's age, which hand was used, and the board size. Spearman rank correlation scores between parents' and children's overall performances gradually increased across age groups (p = -.29, -.10, .47, and .40, respectively, from younger to older age groups). This finding suggests that the potential of youngsters' future performance may be predicted with greater certainty by observing their parents' present performance. This may improve the predictive power of planned programs.     

Influence of multiple categories on the prediction of unknown properties

Knowing an item's category helps us predict its unknown properties. Previous studies suggest that when asked to evaluate the probability of an unknown property, people tend to consider only an item's most likely category, ignoring alternative categories. In the present study, property prediction took the form of either a probability rating or a speeded binary-choice judgment. In keeping with past findings, the subjects ignored alternative categories in their probability ratings. However, their binary-choice judgments were influenced by alternative categories. This novel finding suggests that the way in which category knowledge is used in prediction depends critically on the form of the prediction.     

Premovement activity of the pre-supplementary motor area and the readiness for action: studies of time-resolved event-related functional MRI

The supplementary motor area (SMA) is thought to play in important role in the preparation and organisation of voluntary movement. It has long been known that cortical activity begins to increase up to 2s prior to voluntary self-initiated movement. This increasing premovement activity measured in EEG is known as the Bereitschaftspotential or readiness potential. Modern functional brain imaging methods, using event-related and time-resolved functional MRI techniques, are beginning to reveal the role of the SMA, and in particular the more anterior pre-SMA, in premovement activity associated with the readiness for action. In this paper we review recent studies using event-related time-resolved fMRI methods to examine the time-course of activation changes within the SMA throughout the preparation, readiness and execution of action. These studies suggest that the pre-SMA plays a common role in encoding or representing actions prior to our own voluntary self-initiated movements, during motor imagery, and from the observation of others' actions. We suggest that the pre-SMA generates and encodes motor representations which are then maintained in readiness for action.