The effects of changes in the World Health Organization's International Classification of Diseases on suicide rates in 71 countries, 1950-1999

The World Health Organization (WHO) provides annual mortality statistics from 1950 onward based on the International Classification of Diseases (ICD). In this paper we evaluate the effects of ICD form revisions on suicide rates for 71 countries. The changes between ICD-6, ICD-7, ICD-8, and ICD-9 did not have an overall effect on reported suicide rates. The transitions to ICD-8 and ICD-9 were, however, associated with country-specific changes in the suicide rate in some countries. The change from ICD-9 to ICD-10 was associated with an overall change of -.73 suicides per 100,000 inhabitants. It is recommended that researchers using the WHO mortality data for longitudinal cross-national studies control for the ICD form used at different time points.     

Apolipoprotein e gene variability and cognitive functions at age 79: a follow-up of the Scottish mental survey of 1932

Apolipoprotein E (APOE) genotype is a possible influence on nonpathological cognitive aging. The authors studied 462 community-dwelling, 79-year-old people born in 1921, whose childhood IQ had been assessed in the Scottish Mental Survey of 1932 (Scottish Council for Research in Education, 1933). Adjusting for sex, childhood IQ, and self-reported illnesses, the authors found that those with an APOE e4 allele had significantly lower Wechsler Logical Memory (D. Wechsler, 1987) scores than those without an e4 allele. Those people with APOE s2/e3 genotypes had significantly higher Wechsler Logical Memory scores than e3/s3, who were significantly higher than e3/e4. Neither nonverbal reasoning nor verbal fluency were affected. In this sample, APOE genotype contributed to verbal memory in old age.     

Contextual interference effect on acquisition and retention of pistol-shooting skills

The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three "stages" with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Following a 20-min. safety and skill instructional session, Blocked group practiced 10 trials in a row at each stage, while Serial group performed 5 trials in a row for each of the three stages and then repeated the cycle. Both groups completed a total of 30 practice trials over the three stages. A 10-min. rest interval was provided prior to a retention test which included 9 trials (3 trials at each stage in a blocked format). Results based on the data of Stage III, the most complex skill among the three stages, showed a pattern consistent with previous findings that practicing in the serial schedule depressed performance during initial training but maintained the performance better at retention, relative to the blocked practice.     

Neutralizing substitutes for leadership theory: leadership effects and common-source bias

The purpose of this research was to examine alternative models of substitutes for leadership theory given the general lack of empirical support for the moderating effects postulated by the theory. On this basis, the research posited that the effects of substitutes also could be conceptualized as mediated relations. The research examined moderated and mediated relations for several sets of leader behaviors and substitutes that have been examined in the literature. The research design sampled 49 organizations, with 940 subordinates rating 156 leaders. Results, although generally not supportive of the moderator or mediator hypotheses, essentially demonstrated that leadership matters. The findings also suggest that prior significant effects in substitutes literature may be merely a statistical artifact, resulting from common-source bias.     

Knowledge of partner's ability as a moderator of group motivation gains: an exploration of the Köhler discrepancy effect

O. K?hler (1926, 1927) found that less able performers tried harder as team members under conjunctive task demands (Kohler motivation gain effect) and that the greatest gain occurred with moderately discrepant coworker abilities (K?hler discrepancy effect). Recent investigations have reproduced K?hler's overall motivation gain but not the discrepancy effect. The present research examined whether workers' foreknowledge of task abilities--present in Kohler's research, absent in contemporary studies--moderates the discrepancy effect. Participants worked alone or in 2-person teams under conjunctive task demands. Experiment 1 manipulated foreknowledge of ability. Experiment 2 manipulated discrepancy: a (confederate) teammate performed slightly, moderately, or substantially better. Both experiments found (a) overall motivation gains and (b) discrepancy moderation under foreknowledge conditions. Implications for understanding group motivation gains are discussed.     

Auditory frequency-based inhibition differs from spatial IOR

Uninformative auditory frequency cues have a facilitatory effect on reaction time and accuracy of detection and intensity discrimination of target tones for cue-target intervals of up to 3 sec (Green & McKeown, 2001; Ward, 1997). Under some conditions, however, this facilitatory effect can reverse to an inhibitory effect at cue-target intervals longer than 450 msec (Mondor, Breau, & Milliken, 1998). Thepresent work demonstrates that such inhibitory effects are not found in target-target experiments (Experiment 1) or in cue-target experiments requiring a go-no-go discrimination of the target (Experiment 2), whereas they do appear in the paradigm used by Mondor et al. (1998, Experiment 3), albeit unaffected by the similarity of cue and target. Thus, the frequency-based inhibitory effects sometimes found in auditory cuing tasks can be distinguished empirically from those characterizing spatial inhibition of return (IOR), which are found in both target-target and go-no-go cue-target paradigms. The present work and functional and neurophysiological arguments all support the position that different mechanisms underlie spatial IOR and the inhibitory effects sometimes found in auditory frequency processing.     

Responses to olfactory stimuli in spotted hyenas (Crocuta crocuta): II. Discrimination of conspecific scent

Scent marking in spotted hyenas (Crocuta crocuta) includes the deposition of anal sac secretions, or "paste," and presumably advertises territorial ownership. To test whether captive hyenas classify and discriminate individuals using odor cues in paste, the authors conducted behavioral discrimination bioassays and recorded hyena investigation of paste extracted from various conspecific donors. In Experiment 1, subjects directed most investigative behavior toward scents from unfamiliar hyenas and members of the opposite sex. In Experiment 2, male hyenas discriminated between concurrent presentations of paste from various unfamiliar females in similar reproductive states. Thus, pasted scent marks convey information about the sex, familiarity, and even identity of conspecifics. Aside from territory maintenance, scent marking may also communicate information about individual sexual status.     

When debiasing backfires: accessible content and accessibility experiences in debiasing hindsight

Two studies demonstrated that attempts to debias hindsight by thinking about alternative outcomes may backfire and traced this to the influence of subjective accessibility experiences. Participants listed either few (2) or many (10) thoughts about how an event might have turned out otherwise. Listing many counterfactual thoughts was experienced as difficult and consistently increased the hindsight bias, presumably because the experienced difficulty suggested that there were not many ways in which the event might have turned out otherwise. No significant hindsight effects were obtained when participants listed only a few counterfactual thoughts, a task subjectively experienced as easy. The interplay of accessible content and subjective accessibility experiences in the hindsight bias is discussed.