When does grouping happen?

Recent research on perceptual grouping is described with particular emphasis on identifying the level(s) at which grouping factors operate. Contrary to the classical view of grouping as an early, two-dimensional, image-based process, recent experimental results show that it is strongly influenced by phenomena related to perceptual constancy, such as binocular depth perception, lightness constancy, amodal completion, and illusory contours. These findings imply that at least some grouping processes operate at the level of phenomenal perception rather than at the level of the retinal image. Preliminary evidence is reported showing that grouping can affect perceptual constancy, suggesting that grouping processes must also operate at an early, preconstancy level. If so, grouping may be a ubiquitous, ongoing aspect of visual organization that occurs for each level of representation rather than as a single stage that can be definitively localized relative to other perceptual processes.     

The meaning of life (events) predicts changes in attachment security

Building on prior research, which has failed to find consistent effects of life events on change in self-reported adult attachment security over time, the present study tested the hypothesis that it is the meaning people attach to events, rather than the objective features of events, that is associated with changing levels of security. Participants engaged in an 8-week daily diary study, during which they completed daily self-report measures of attachment security, negative life events, perceptions of loss associated with events, and mood. Hierarchical linear modeling revealed that perceptions of greater interpersonal (but not achievement) loss associated with life events were significantly associated with greater insecurity on a day-to-day basis, even controlling for objective features of events and for mood. Trait levels of security did not moderate this association. Results are discussed with regard to social-cognitive models of attachment security and the utility of understanding the meaning of life events to understand how attachment models may be confirmed or disconfirmed.     

What types of visual recognition tasks are mediated by the neural subsystem that subserves face recognition?

Three divided visual field experiments tested current hypotheses about the types of visual shape representation tasks that recruit the cognitive and neural mechanisms underlying face recognition. Experiment 1 found a right hemisphere advantage for subordinate but not basic-level face recognition. Experiment 2 found a right hemisphere advantage for basic but not superordinate-level animal recognition. Experiment 3 found that inverting animals eliminates the right hemisphere advantage for basic-level animal recognition. This pattern of results suggests that the cognitive and neural mechanisms underlying face recognition are recruited when computational demands of a shape representation task are best served through the use of coordinate (rather than categorical) spatial relations.     

Factor structure and interpretation of the K10

The Kessler 10 Psychological Distress Scale (K10) is a brief 10-item questionnaire designed to measure the level of distress and severity associated with psychological symptoms in population surveys. It is being used widely, including in the World Health Organization World Mental Health Survey, and as a clinical outcome measure, although little information is available about the structure of the measure. The factorial composition of the K10 was examined in a prospective community survey and cross-validated in a separate large community survey. The K10 was found to consist of 4 factors and a 2-factor second-order factor structure. This was stable across the 2 waves of the prospective study and the Australian National Survey of Mental Health and Well-Being. The 4 factors, labeled Nervous, Negative Affect, Fatigue, and Agitation, were consistent with the original scales from which the items were taken. The 2 second-order factors represent Depression and Anxiety.     

Risk perception and acceptance--one process or two? The impact of aspirations on perceived risk and preferences

The experiments discussed here are aimed at determining whether risk perception and risk acceptance are two distinct psychological processes. This study is motivated by the idea of a double-criterion model of choice. In particular, in line with risk-value (R-V) models, in which risk is treated as a primitive, it is tested whether risk is independent of aspirations and whether preferences depend on aspirations. In two experiments, 305 university students were presented with pairs of risky projects and were asked to compare their riskiness and select one. The aspiration level, defined as the target return on the project, was set through an explicit instruction. In Experiment 1, a within-subject designwas applied, and thus aspirations were set at two different levels. In Experiment 2, with a between-subject design, two different aspiration levels were set for each group. The results indicate that risk ordering is insensitive to changes in aspirations, but preferences are sensitive to those changes. This supports distinctness of risk perception and risk acceptance. The findings are discussed in terms of the CPT and SP/A models and the R-V approach. It appears that double-criterion models provide better and psychologically sounder predictions of subjects' preferences.     

Food caching by western scrub-jays (Aphelocoma californica) is sensitive to the conditions at recovery

Western scrub-jays (Aphelocoma californica) cached perishable and nonperishable food items, which they could recover after both short and long retention intervals. When perishable items were always degraded at recovery, jays decreased the number of perishable items cached and increased their caching of nonperishable items, relative to a control group whose caches were always fresh at recovery. Jays reduced the number of nonperishable items cached, however, when highly preferred food items were degraded only after the long retention intervals. The findings are discussed in terms of the role of retrospective and prospective processes in the control of caching.     

Monocular motion adaptation affects the perceived trajectory of stereomotion

Perceived stereomotion trajectory was measured before and after adaptation to lateral motion in the dominant or nondominant eye to assess the relative contributions of 2 cues: changing disparity and interocular velocity difference. Perceived speed for monocular lateral motion and perceived binocular visual direction (BVD) was also assessed. Unlike stereomotion trajectory perception, the BVD of static targets showed an ocular dominance bias, even without adaptation. Adaptation caused equivalent biases in perceived trajectory and monocular motion speed, without significantly affecting perceived BVD. Predictions from monocular motion data closely match trajectory perception data, unlike those from BVD sources. The results suggest that the interocular velocity differences make a significant contribution to stereomotion trajectory perception.     

Letter detection in very familiar texts

In the present study, we investigated whether patterns of letter detection for function and content words in texts are affected by the familiarity of the material being read. In Experiment 1, subjects searched for target letters in sentences that had been rehearsed prior to performing the letter detection on them as well as on unfamiliar sentences. In Experiment 2, subjects searched for target letters in highly familiar verses (e.g., nursery rhymes) and in unfamiliar sentences that were matched to the familiar verses. A disadvantage in letter detection for function as compared with content words consistently found with unfamiliar passages was reduced significantly with the familiar material in both experiments. Specifically, letter detection for content words grew worse in familiar text, but letter detection for function words showed a contrasting modest, though nonsignificant, improvement. The results are consistent with the proposition that in very familiar texts, parafoveal analysis permits the identification of generally less familiar content words. Simultaneously, the normal pattern of weighing the structure and content elements of text changes so that more fixations on function words occur than when one is reading unfamiliar texts.     

Externalizing Symptomatology Among Adoptive Youth: Prevalence and Preadoption Risk Factors

The extent of symptomatology related to attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) was examined in a statewide sample of adopted youth, aged 4–18 years (n = 808). The use of normed questionnaires in a nonclinical sample decreased biases associated with past research on adopted children. According to parental report, a striking number of the youth qualified as manifesting significant symptom levels of externalizing behavior problems: 21% met symptom cutoffs for ADHD (with or without ODD) and 20% met criteria for ODD (with or without ADHD), for a combined total of 29% of the sample. A number of parent-reported, preadoptive risk factors distinguished these groups from one another and from the nonexternalizing youth. The clearest associated factors included histories of preadoption abuse/neglect, later age of adoption, prenatal drug exposure, and placement in multiple foster homes prior to adoption. We discuss implications regarding both etiology and current controversies surrounding the disproportionate levels of behavioral difficulties in adopted youth.     

A meta-analytic approach to growth curve analysis

A meta-analytic approach to growth curve analysis is described and illustrated by applying it to the evaluation of the Arizona Pilot Project, an experimental project for financing the treatment of the severely mentally ill. In this approach to longitudinal data analysis, each individual subject for which repeated measures are obtained is initially treated as a separate case study for analysis. This approach has at least two distinct advantages. First, it does not assume a balanced design (equal numbers of repeated observations) across all subjects; to accommodate a variable number of observations for each subject, individual growth curve parameters are differentially weighted by the number of repeated measures on which they are based. Second, it does not assume homogeneity of treatment effects (equal slopes) across all subjects. Individual differences in growth curve parameters representing potentially unequal developmental rates through time are explicitly modeled. A meta-analytic approach to growth curve analysis may be the optimal analytical strategy for longitudinal studies where either (1) a balanced design is not feasible or (2) an assumption of homogeneity of treatment effects across all individuals is theoretically indefensible. In our evaluation of the Arizona Pilot Project, individual growth curve parameters were obtained for each of the 13 rationally derived subscales of the New York Functional Assessment Survey, over time, by linear regression analysis. The slopes, intercepts, and residuals obtained for each individual were then subjected to meta-analytic causal modeling. Using factor analytic models and then general linear models for the latent constructs, the growth curve parameters of all individuals were systematically related to each other via common factors and predicted based on hypothesized exogenous causal factors. The same two highly correlated common factors were found for all three growth curve parameters analyzed, a general psychological factor and a general functional factor. The factor patterns were found to be nearly identical across the separate analyses of individual intercepts, slopes, and residuals. Direct effects on the unique factors of each subscale of the New York Functional Assessment Survey were tested for each growth curve parameter by including the common factors as hierarchically prior predictors in the structural model for each of the indicator variables, thus statistically controlling for any indirect effect produced on the indicator through the common factors. The exogenous predictors modeled were theoretically specified orthogonal contrasts for Method of Payment (comparing Arizona Pilot Project treatment or "capitation" to traditional or "fee-for-service" care as a control), Treatment Administration Site (comparing various locations within treatment or control groups), Pretreatment Assessment (comparing general functional level at intake as assigned by an Outside Assessment Team), and various interactions among these main effects. The intercepts, representing the initial status of individual subjects on both the two common factors and the 13 unique factors of the subscales of the New York Functional Assessment Survey, were found to vary significantly across many of the various different treatment conditions, treatment administration sites, and pretreatment functional levels. This indicated a severe threat to the validity of the originally intended design of the Arizona Pilot Project as a randomized experiment. When the systematic variations were statistically controlled by including intercepts as hierarchically prior predictors in the structural models for slopes, recasting the experiment as a nonequivalent groups design, the effects of the intercepts on the slopes were found to be both statistically significant and substantial in magnitude. (ABSTRACT TRUNCATED)