The partial reinforcement extinction effect (PREE), defined as increased behavioral persistence following intermittent reward, is considered an important outcome of instrumental learning contingencies, both inside and outside the laboratory. Since adults have a rich experience with situations in which desired outcomes depend on instrumental responding, we asked whether that experience affects judgments of persistence when relevant contingency information is manipulated. Subjects read simple scenarios with information about behaviors generated by high vs. low reward rate, and then judged the resultant persistence of these behaviors under no-reward conditions. Studies 1 and 2 found no evidence that persistence judgments were affected by contingency information in naive subjects. Studies 3 and 4 compared groups with and without explicit knowledge about behavioral psychology and thus tested possible effects of that knowledge for persistence more directly. Judgments in naive subjects were not reliably influenced by reward rate information, but subjects possessing expert knowledge demonstrated judgments that were reliably affected by contingency information. The results indicate that people do not generate generalized knowledge from normal experience with occasional vs. regular reward. Possible explanations and implications of these findings are discussed.
Geographical differences in the frequencies of eight common surnames in Jutland (Denmark) are analysed using data from telephone directories of 121 exchanges. All the names showed a significant geographical surplus variance, which was divided into trend and patchiness components reflecting the history of the names. The surplus variance of surnames with restricted areas of origin was dominated by a large trend component; for surnames with an originally more even distribution, the patchiness component was dominant. The patterns of distribution were affected by processes which modelled natural selection with linkage disequilibrium. The combined patchiness within the clusters of exchanges gave information about patterns of local migration and level of social integration in the communities. Areas situated in boundary regions show high levels of patchiness.
This study explores the role of morphology in vocabulary knowledge of 3rd and 6th grade Finnish elementary school children. In a word definition task, children from both grades performed overall better on derived words than on monomorphemic words. However, the results were modified by the factors Frequency and Productivity. Most strikingly, performance on monomorphemic words was disproportionately weaker than on derived words at the low frequency range. At the high-frequency range, derived words with low-productive suffixes yielded poorest performance. We partly make an appeal to the lexical-statistical properties of the Finnish language to explain the interaction of Frequency and Word Structure. At any rate, the results suggest that Finnish elementary school children benefit significantly from utilizing morphology in determining word meanings.
The relation between attention at encoding and direct (i.e., recognition) versus indirect (i.e., rapid reading) remembering was investigated. In Experiments 1 and 2, color of print indicated whether to read an individual word aloud or to ignore it. This attentional manipulation reduced direct but not indirect remembering for the ignored words relative to the attended words. Apparently direct remembering is extremely dependent on attention at encoding. In Experiment 3, however, presenting two words simultaneously at study, with color now signifying which word to read and which to ignore, eliminated this dissociative effect of attention. Ignored words were not remembered on either test, although attended words were remembered well on both. Mere exposure is not sufficient to produce indirect remembering: Stimuli must be attended. Ignoring one stimulus in favor of processing another stimulus that is simultaneously presented and equally salient may prevent even the minimal attentional requirements of indirect remembering from being met, let alone the more stringent requirements of direct remembering.
The familial resemblance for immunoglobulin A, D, E, G, and M levels was investigated with family data collected in Canada and the U.S., entertaining both multifactorial and single gene hypotheses. Significant familial effects were found for each of the immunoglobulins, and there was significant support for a major gene hypothesis for IgA and IgD levels. Whereas there have been several reports suggesting a major gene determinant for IgE levels, including that from our own Canadian study, analysis of the U.S. sample suggested that a multifactorial component parsimoniously explained the observed familial resemblance.
The goal of this study was to examine the effects of noise and whole-body vibration, individually and combined, and at various stimulus intensity levels, on cognitive performance and subjective experience.
Fifty-four participants (27 men and 27 women) with a mean age of 25 years, ranging from 19 to 30, were exposed for 20 min each to a 16-Hz sinusoidal whole-body vibration, a helicopter sound at 21 Hz, both stimuli combined, and a control condition. Participants were randomly assigned to one of three groups: low intensity [77 dB(A) noise and 1.0 m/s2 vibration], medium intensity [81 dB(A)/1.6 m/s2] or high intensity [86 dB(A)/2.5 m/s2. During each environmental exposure, short-term memory performance was tested with a visual Sternberg paradigm. Reaction time was measured as a dependent variable. Directly following each environmental exposure, participants rated the difficulty of the task and the annoyance level of the exposure stimulus.
Results revealed no significant changes in reaction times due to environmental exposure or intensity level. However, participants significantly rated the combined exposure as both more annoying and more difficult than the other conditions. Further, the high-intensity group rated subjective annoyance significantly higher than the other groups for all conditions.
The results from this study indicate that performance alone is not a sufficient measure for the study of the effects of combined stimuli on a human operator.
Samples of individuals born between 1956 and 1971 proportional to the population size of each parish of Saguenay-Lac-St-Jean (SLSJ) were extracted from a computerized population register. The mean inbreeding and kinship coefficients were calculated for each sample. Our results showed that inbreeding and kinship were unevenly distributed in the SLSJ region. The highest values of inbreeding and kinship were found in Bas-Saguenay, an isolated subregion of SLSJ, and in rural parishes. It was also found that the mean inbreeding and kinship coefficients had higher values in parishes that opened between 1872 and 1901 than those opened earlier or later.
Marsh, Ward, and Landau (1999) demonstrated that participants asked to create novel words use elements of sample nonwords they are given, even when instructed to avoid use of the examples. In four studies, we replicated the effect of conformity to sample nonwords and found the effect was not influenced by the semantic category of the words unless those words shared orthographic characteristics. We found that although we could increase conformity to examples when word exemplars were grouped by category, it was likely that much of this increase was strategically driven. We propose that the presence of the sample non-words, presented in groups with the same word rules, created an orthographic category used by participants in the word creation task.
This study shows how a Gibbs sampling approach can be used for Bayesian inference of inbreeding depression. The method presented is mainly concerned with organisms that can be both selfed and outcrossed. Tests performed on simulated data with unequal variances and missing observations show that the method works well. Real data from the plant Scabiosa canescens is also analyzed.