How surprising is a simple pattern? Quantifying "Eureka!"

Simple patterns are compelling. When all the observed facts fit into a simple theory or "story," we are intuitively convinced that the pattern must be real rather than random. But how surprising is a simple pattern, really? That is, given a pattern of featural data, such as the properties of a set of objects, how unlikely would the pattern be if they were actually generated at random? In conventional statistics dealing with patterns of numbers, this type of question would be answered by reference to a null distribution such as the t distribution. This paper gives the analogous answer in the realm of concept learning, that is, the formation of generalizations from patterns of featural data. Using a formal but psychologically valid definition of complexity, I derive and exhibit the distribution of subjective complexity under the hypothesis of no pattern. This leads directly to a number of applications, including a statistical test indicating whether an observed pattern is sufficiently simple that it is not likely to have been an accident: literally, the "significance of simplicity."     

Parent-infant synchrony and the social-emotional development of triplets

To study the social-emotional development of triplets, 23 sets of triplets, 23 sets of twins, and 23 singleton infants (N=138) were followed from birth to 2 years. Maternal depression and social support were assessed in the postpartum period, mother-infant and father-infant interaction and the home environment were observed at 3 months, a separation-reunion episode and a maternal interview were conducted at 12 months, and infant behavior problems were evaluated at 24 months. Lower parent-infant synchrony was observed for triplets. Triplets showed less distress during maternal separation and less approach at reunion. Mothers reported lower adjustment and differentiation among siblings for triplets than for twins. Higher internalizing problems were reported for triplets, and the triplet with intrauterine growth retardation showed the poorest outcomes. Behavior problems were predicted by medical risk, maternal depression, parent-infant synchrony, infant approach, and mother adjustment. Discussion focuses on developmental risk when the exclusivity of the parent-infant relationship is compromised.     

Categorical and dimensional reports of experienced affect to emotion-inducing pictures in depression

Self-reported affect to positive and negative emotional pictures was contrasted in people with major depressive disorder (MDD) and never-depressed control participants (n = 25 in each group). The results revealed significant differences in response to positive images (reduced arousal, less pleasant valence, decreased happiness, increased sadness) in MDD but no clear group differences in response to negative stimuli. Extending earlier findings of reduced responsiveness to positive, but not negative, stimuli in MDD (D. M. Sloan, M. E. Strauss, S. W. Quirk, & M. Satajovik, 1997; D. M. Sloan, M. E. Strauss, & K. L. Wisner, 2001), the data indicate that blunted response to positive stimuli is found when both categorical and dimensional ratings are elicited. Further, the data replicate earlier findings of elevated sadness reports to positive stimuli (J. Rottenberg, K. L. Kasch, J. J. Gross, & I. H. Gotlib, 2002), which may reflect broader difficulties in regulating emotions in MDD.     

Sleep quality, sleep propensity and academic performance

We examined associations between measures of sleep propensity on the Epworth Sleepiness Scale, sleep quality on the Pittsburgh Sleep Quality Index and academic performance by GPA and grades in introductory psychology for 414 students. In the total sample, neither sleep propensity nor sleep quality correlated with GPA or introductory psychology grades. However, among students carrying a full course load, those reporting poor sleep quality performed less well on academic measures than those reporting a better quality of sleep. Further research is needed to assess the moderating influence of overall demands of daytime functioning on the association between sleep quality and academic performance.     

Some characteristics of auditory spatial attention revealed using rhythmic masking release

The tuning of auditory spatial attention with respect to interaural level and time difference cues (ILDs and ITDs) was explored using a rhythmic masking release (RMR) procedure. Listeners heard tone sequences defining one of two simple target rhythms, interleaved with arhythmic masking tones, presented over headphones. There were two conditions, which differed only in the ILD of the tones defining the target rhythm: For one condition, ILD was 0 dB and the perceived lateral position was central, and for the other, ILD was 4 dB and the perceived lateral position was to the right; target tone ITD was always zero. For the masking tones, ILD was fixed at 0 dB and ITDs were varied, giving rise to a range of lateral positions determined by ITD. The listeners' task was to attend to and identify the target rhythm. The data showed that target rhythm identification accuracy was low, indicating that maskers were effective, when target and masker shared spatial position, but not when they shared only ITD. A clear implication is that at least within the constraints of the RMR paradigm, overall spatial position, and not ITD, is the substrate for auditory spatial attention.     

A Review of Spiritual and Religious Measures in Nursing Research Journals: 1995--1999

Background: A series of systematic reviews has revealed relatively high levels of interest in religion and spirituality in different nursing specialties, but not in general nursing research journals. Purpose: To identify the extent to which spirituality and religiousness were measured in all quantitative and qualitative research articles published in Research in Nursing and Health, Nursing Research, Advances in Nursing Science (ANS), and Image: The Journal of Nursing Scholarship from 1995 to 1999. Methods: A full-text search was conducted of ANS and Image using the Ovid search system. Nursing Research and Research in Nursing and Health were hand searched for spiritual/religious measures. Characteristics of selected studies, the measures taken, and their uses were coded for data analysis. Results: A total of 564 research studies were identified, of which 67 (11.9%) included at least one measure of spirituality or religiousness. A significant difference was found between the percentage of qualitative and quantitative studies that contained measures of these concepts. Of the 119 qualitative studies, 23 (19.3%) contained a measure of religion or spirituality, compared to 44 of the 445 (9.9%) quantitative studies. Nominal indicators of religious affiliation were the most commonly used measures in the quantitative studies and measures of religion and spirituality were rarely used in the analyses. Although only a few quantitative or qualitative studies intended to focus on religion or spirituality, these themes often emerged spontaneously in the qualitative research. Conclusions: Research in Nursing and Health, Advances in Nursing Science, Nursing Research, and Image: The Journal of Nursing Scholarship all published research measuring spirituality and religiousness during the time-period studied. The rate at which spirituality and religion appeared in these nursing research articles is substantially higher than that found in most fields outside of nursing. Even more frequent inclusion of spiritual and religious variables and richer measures of spirituality and religiousness would help to increase the available scientific information on the role of spirituality and religion in nursing care.     

Well-being and the anticipation of future positive experiences: The role of income, social networks, and planning ability

The present study aims to answer two questions: (1) are expectations of future positive experiences related to well-being in the general population?; and (2) what factors (social, psychological, economic) enable people to have expectations of future positive experiences. A community sample (N = 84) was assessed on a measure of anticipation of future positive and negative experiences, factors that might enable positive anticipation (measures of income, social networks, planning ability, and affective capacity) and measures of subjective well-being (positive and negative affect and life satisfaction). Subjective well-being was related to having more anticipated positive experiences, which was in turn related to having a large social network, having a high number of steps in plans to achieve goals, and, more marginally, to having a high household income.     

Do humans integrate routes into a cognitive map? Map- versus landmark-based navigation of novel shortcuts

Do humans integrate experience on specific routes into metric survey knowledge of the environment, or do they depend on a simpler strategy of landmark navigation? The authors tested this question using a novel shortcut paradigm during walking in a virtual environment. The authors find that participants could not take successful shortcuts in a desert world but could do so with dispersed landmarks in a forest. On catch trials, participants were drawn toward the displaced landmarks whether the landmarks were clustered near the target location or along the shortcut route. However, when landmarks appeared unreliable, participants fell back on coarse survey knowledge. Like honeybees (F. C. Dyer, 1991), humans do not appear to derive accurate cognitive maps from path integration to guide navigation but, instead, depend on landmarks when they are available.