The perception of briefly exposed point-sources of light

Point-sources of light (dots) were exposed for 10 to 50 msec, before five dark-adapted subjects in a dimly illuminated room. During voluntary fixation with one eye, the target was exposed some 10° on the nasal side of the optic axis. The intensity X duration of all targets was 2 X threshold and they consisted of either a single dot, or a pair of dots separated by a distance that was less than that required for two-point discrimination. In two-thirds of trials both the single-dot and the two-dot targets were perceived as short thin lines of various orientation. Although individual percepts were unpredictable, there was a preferred or most likely orientation for responses to the single-dot target; this was near to the horizontal for all five subjects. There was no significant difference between the preferred orientations for single-dot targets tested at sites more than 1° apart in the visual field. When two single-dot targets, separated by about 1°, were exposed simultaneously, the orientations of the perceived lines sometimes differed by as much as 80°; occasionally, one target was reported as a dot while the other was seen as a thin line. If the single-dot was briefly exposed between two continuously visible and parallel straight lines, the target usually appeared as a thin line, parallel to the framing lines. Some of these results appear to be consistent with the hypothesis that the human visual cortex, like that of the cat and monkey, contains neurones that are orientation specific.     

Accuracy of person perception: do people know what kinds of impressions they convey?

Do people know what kinds of impressions they convey to other people during particular social interactions? In a study designed to answer this question, subjects interacted individually with three partners on each of four different tasks. After each interaction, participants reported their impressions of the other person's likability and competence. They also postdicted the impressions they believed they conveyed to the other person along the same dimensions. Accuracy was computed as recommended by Cronbach (1955) and by Kenny's (1981) Social Relations Model. Subjects could tell to a significant degree how the impressions they conveyed to their partners changed over time (time accuracy) and how they changed over time in different ways with different partners (differential accuracy). They could also tell how their competence was differentially perceived by different partners (dyadic accuracy). However, they were not very accurate at discerning which partners perceived them as most competent or most likable across all interactions (person accuracy). Subjects believed that they conveyed similar impressions of themselves to all of their partners, although actually partners evidenced little agreement with each other in their impressions of a given subject. The implications of these findings for symbolic-interactionist theories of the development of the self and impression-management perspectives on social behavior are described.     

The City Infant Faces Database: A validated set of infant facial expressions

Adults need to be able to process infants’ emotional expressions accurately to respond appropriately and care for infants. However, research on processing of the emotional expressions of infant faces is hampered by the lack of validated stimuli. Although many sets of photographs of adult faces are available to researchers, there are no corresponding sets of photographs of infant faces. We therefore developed and validated a database of infant faces, which is available via e-mail request. Parents were recruited via social media and asked to send photographs of their infant (0–12 months of age) showing positive, negative, and neutral facial expressions. A total of 195 infant faces were obtained and validated. To validate the images, student midwives and nurses (n = 53) and members of the general public (n = 18) rated each image with respect to its facial expression, intensity of expression, clarity of expression, genuineness of expression, and valence. On the basis of these ratings, a total of 154 images with rating agreements of at least 75% were included in the final database. These comprise 60 photographs of positive infant faces, 54 photographs of negative infant faces, and 40 photographs of neutral infant faces. The images have high criterion validity and good test–retest reliability. This database is therefore a useful and valid tool for researchers.     

An automated approach to measuring child movement and location in the early childhood classroom

Children’s movement is an important issue in child development and outcome in early childhood research, intervention, and practice. Digital sensor technologies offer improvements in naturalistic movement measurement and analysis. We conducted validity and feasibility testing of a real-time, indoor mapping and location system (Ubisense, Inc.) within a preschool classroom. Real-time indoor mapping has several implications with respect to efficiently and conveniently: (a) determining the activity areas where children are spending the most and least time per day (e.g., music); and (b) mapping a focal child’s atypical real-time movements (e.g., lapping behavior). We calibrated the accuracy of Ubisense point-by-point location estimates (i.e., X and Y coordinates) against laser rangefinder measurements using several stationary points and atypical movement patterns as reference standards. Our results indicate that activity areas occupied and atypical movement patterns could be plotted with an accuracy of 30.48 cm (1 ft) using a Ubisense transponder tag attached to the participating child’s shirt. The accuracy parallels findings of other researchers employing Ubisense to study atypical movement patterns in individuals at risk for dementia in an assisted living facility. The feasibility of Ubisense was tested in an approximately 90-min assessment of two children, one typically developing and one with Down syndrome, during natural classroom activities, and the results proved positive. Implications for employing Ubisense in early childhood classrooms as a data-based decision-making tool to support children’s development and its potential integration with other wearable sensor technologies are discussed.     

Social risk and protective factors for suicide attempts in low income African American men and women

A case-control study was conducted to examine a broad array of potential social risk and protective factors for suicide attempt among 200 African American men and women receiving care at a large, public, urban hospital. Specifically, we examined the effect of the following potential risk factors for suicide attempt: life hassles, partner abuse, partner dissatisfaction, and racist events; as well as the following potential protective factors: effectiveness of obtaining resources, social embeddedness, and social support. Using logistic regression, suicide attempter status was predicted by two independently significant social variables: one risk factor (life hassles) and one protective factor (social support). Male versus female suicide attempters were not distinguished by the social variables. These findings, which support the utility of an ecological conceptualization of risk and protective factors for suicide attempt, help to clarify the independently significant social environment risk and protective factors for suicide attempts among economically disadvantaged African Americans in particular. Research on both risk factors and protective factors provide a basis for culturally competent interventions aimed at reducing both the risk of future suicide attempts and completions.