Age related changes in the effectiveness of name and visual codes in recognition memory

In the first of three studies college, third grade, and kindergarten Ss were able to determine that two stimuli presented 700 msec apart were the same more quickly if they were visually identical than if they shared the same name. If 3000 msec elapsed between stimulus presentations third grade and college Ss responded at the same rate in making both types of matches, whereas kindergarten Ss appeared to continue to respond more quickly in making visual matches. Study II was an unsuccessful attempt to replicate the kindergarten finding. A warning signal, presented 500 msec prior to the second stimulus, reduced RTs at both interstimulus intervals, but no significant differences in making visual and name matches occurred. In Study III first-graders, responding either with or without a warning signal, were found to respond like the older Ss in Study I. The warning signal again reduced RT at both intervals. The results suggest that Ss across a wide age range are able to use the visual properties of a stimulus for only a very brief period as the basis for making matching judgments.     

A comparison of different measures of response strength in the study of stimulus generalization

In Experiment 1, three pigeons were given variable interval training to peck at a light of 550 mmu and then were tested for stimulus generalization in extinction to several different wavelengths. A gradient was obtained for latency of the first response in each test period, for the number of test periods in which responding occurred, and for the measure of response rate. When the response rate gradient was corrected for differences in initial latency and in number of responded trials, the change was minimal, indicating that the major component of response rate as usually measured is rate of responding having once responded. In Experiment 2, three other pigeons were trained to respond to 550 mmu (for variable interval reinforcement) and not to 570 mmu (extinguished). Analysis of generalization gradients dictated the same conclusion as that reported for generalization following single stimulus training.     

Testing a model of suicide ideation in college students

This study examined several risk factors-negative life events (NLE), hopelessness, and depressive symptoms-believed to commonly precipitate suicide ideation in college students. A total of 345 undergraduates participated in the study. Students completed four self-report questionnaires. Hierarchical regression analyses were used to construct a risk model of suicide ideation. This study confirmed depressive symptoms and hopelessness as predictors of suicide ideation in college students; however, NLE impacted suicidal thoughts through hopelessness and depressive symptoms. Interestingly, depressive symptoms exerted a stronger influence on suicide ideation than hopelessness. Hopelessness served as a partial mediator in the relationship between NLE and depressive symptoms; however, depressive symptoms fully mediated the relationship between NLE and hopelessness. Clinical implications for understanding suicide risk in college students are discussed.     

Memory storage and retrieval within and across modalities in children

Twenty-four kindergarten and fourth grade children were asked to locate a display card which had been visually or verbally presented. A probe, which identified the card to be located, was presented verbally and visually equally often. The children's ability to recall the location of an item did not differ as a function of the modality to which the material was presented. Nor was recall significantly affected when the presentation modality differed from the probe modality, suggesting that children as young as 5 can cross these sensory modalities to retrieve material with no loss in accuracy. Serial position curves suggest that the verbal and visual material is not stored in a common intersensory store. The primacy effect is found to be stronger with visually presented material and the recency effect strongest with auditorily presented material. Probe modality did not influence the serial position curves.     

Telemedicine in Primary Health: The Virtual Doctor Project Zambia

Physician-researchers are bound by professional obligations stemming from both the role of the physician and the role of the researcher. Currently, the dominant models for understanding the relationship between physician-researchers' clinical duties and research duties fit into three categories: the similarity position, the difference position and the middle ground. The law may be said to offer a fourth "model" that is independent from these three categories. These models frame the expectations placed upon physician-researchers by colleagues, regulators, patients and research participants. This paper examines the extent to which the data from semi-structured interviews with 30 physician-researchers at three major pediatric hospitals in Canada reflect these traditional models. It seeks to determine the extent to which existing models align with the described lived experience of the pediatric physician-researchers interviewed. Ultimately, we find that although some physician-researchers make references to something like the weak version of the similarity position, the pediatric-researchers interviewed in this study did not describe their dual roles in a way that tightly mirrors any of the existing theoretical frameworks. We thus conclude that either physician-researchers are in need of better training regarding the nature of the accountability relationships that flow from their dual roles or that models setting out these roles and relationships must be altered to better reflect what we can reasonably expect of physician-researchers in a real-world environment.