Changing predictions, stable recognition: Children's representations of downward incline motion.

Various studies to-date have demonstrated children hold ill-conceived expressed beliefs about the physical world such as that one ball will fall faster than another because it is heavier. At the same time, they also demonstrate accurate recognition of dynamic events. How these representations relate is still unresolved. This study examined 5- to 11-year-olds' (N = 130) predictions and recognition of motion down inclines. Predictions were typically in error, matching previous work, but children largely recognized correct events as correct and rejected incorrect ones. The results also demonstrate while predictions change with increasing age, recognition shows signs of stability. The findings provide further support for a hybrid model of object representations and argue in favour of stable core cognition existing alongside developmental changes. Statement of contribution What is already known on this subject? Children's predictions of physical events show limitations in accuracy Their recognition of such events suggests children may use different knowledge sources in their reasoning What the present study adds? Predictions fluctuate more strongly than recognition, suggesting stable core cognition But recognition also shows some fluctuation, arguing for a hybrid model of knowledge representation.

Developing understanding of object fall: Going beyond inhibitory processes.

A study is reported where 118 participants aged between 10 years and early 20s drew the trajectories they expected objects to follow as they fell. The younger participants typically anticipated backward trajectories during fall from moving carriers while forward but non-parabolic trajectories were relatively more frequent amongst the older participants. Both patterns suggest strong sociocultural influences, with implications for models that regard development in this area as purely the inhibition of principles established in infancy. Statement of contribution What is already known on this subject? Research with infants demonstrates an early-established belief that dropped objects fall straight down. The erroneous expectations that pre-schoolers hold about object fall are consistent with failure to inhibit the presumption of straight-down fall, in contexts where it is inappropriate. What does this study add? The research replicates and extends research with older participants, which indicates errors that cannot be explained via failed inhibition of straight-down fall. It is the first study to trace patterns of errors across late childhood, adolescence and early adulthood. A consequence of the findings is that adequate modelling in developmental psychology must consider multilayered interactions between prior representations and sociocultural experiences.

Children's conceptions of physical events: explicit and tacit understanding of horizontal motion.

The conceptual understanding that children display when predicting physical events has been shown to be inferior to the understanding they display when recognizing whether events proceed naturally. This has often been attributed to differences between the explicit engagement with conceptual knowledge required for prediction and the tacit engagement that suffices for recognition, and contrasting theories have been formulated to characterize the differences. Focusing on a theory that emphasizes omission at the explicit level of conceptual elements that are tacitly understood, the paper reports two studies that attempt clarification. The studies are concerned with 6- to 10-year-old children's understanding of, respectively, the direction (141 children) and speed (132 children) of motion in a horizontal direction. Using computer-presented billiards scenarios, the children predicted how balls would move (prediction task) and judged whether or not simulated motion was correct (recognition task). Results indicate that the conceptions underpinning prediction are sometimes interpretable as partial versions of the conceptions underpinning recognition, as the omission hypothesis would imply. However, there are also qualitative differences, which suggest partial dissociation between explicit and tacit understanding. It is suggested that a theoretical perspective that acknowledges this dissociation would provide the optimal framework for future research.

Everyday conceptions of object fall: explicit and tacit understanding during middle childhood.

Adults make erroneous predictions about object fall despite recognizing when observed displays are correct or incorrect. Prediction requires explicit engagement with conceptual knowledge, whereas recognition can be achieved through tacit processing. Therefore, it has been suggested that the greater challenge imposed by explicit engagement leads to elements of conceptual understanding being omitted from prediction that are included in recognition. Acknowledging that research with children provides a significant context for exploring this "omission hypothesis" further, this article reports two studies with 6- to 10-year-olds, each of which used prediction and recognition tasks. Study 1 (N=137) focused on understanding of direction of fall, and Study 2 (N=133) addressed speed. Although performance on the recognition tasks was generally superior to performance on the prediction tasks, qualitative differences also emerged. These differences argue against interpreting explicit level understanding purely in terms of omission of tacit constructs, and the article outlines alternative models that may account for the data.

Psychosocial mediators and moderators of the effect of peer-victimization upon depressive symptomatology.

BACKGROUND: Intervention strategies and developmental models of stress have been criticized for failing to integrate social psychological variables. This study investigates both self-referential cognitive mediators (perceived threat and control) and a social psychological moderator (ethnic/religious identity) of the effect of peer-victimization upon depressive symptomatology. METHODS: Self-report questionnaires were completed by 924 students (46% female), aged 8 to 12 years. Experiences of discriminatory and non-discriminatory peer-victimization, threat and control appraisals, depressive symptoms, and strength of main identity were assessed. RESULTS: Perceived threat partially mediated the effect of peer-victimization (regardless of whether it was discriminatory or not) on depressive symptoms. Perceived control partially mediated the effect of non-discriminatory peer-victimization on depressive symptoms. Strength of ethnic/religious identity buffered the effect of peer-victimization on depressive symptoms. Victimization perceived to be discriminatory in nature was more strongly associated with depressive symptoms than non-discriminatory victimization. CONCLUSIONS: Findings support calls for a greater emphasis to be placed on social psychological variables in explaining depressive symptomatology. For clinical, counseling and intervention purposes, it is important to examine whether victims perceive peer-victimization as discriminatory and whether their own strength of identity affects symptomatology.

Intensive quantities: why they matter to developmental research.

A distinction can be drawn between extensive and intensive quantities. Extensive quantities (e.g., volume, distance), which have been the focus of developmental research, depend upon additive combination. Intensive quantities (e.g., density, speed), which have been relatively neglected, derive from proportional relations between variables. Thus, while proportional relations can be expressed with extensive quantities, these relations are constitutive with intensive quantities. One consequence is that factors, which are theorized as marginal with extensive quantities, are conceptually central in intensive contexts, and may need to be recognized in developmental models. Two such factors, termed variable salience and relational focus, are examined here, via a study where 963 Scottish children aged 7-12 years were asked to solve 42 intensive quantity problems in comparison and missing value format. Reasoning improved with age, but at all ages it was strongly influenced by variable salience and relational focus. Moreover, the manner in which these two factors interacted with other factors differed from what might be expected from models of proportional reasoning with extensive quantities. Based upon these results, it is argued that the distinction between extensive and intensive quantities is theoretically significant, and intensive quantities need to be granted more attention in the future.

Cigarette smoking, body mass index, gastro-esophageal reflux disease, and non-steroidal anti-inflammatory drug use and risk of subtypes of esophageal and gastric cancers by P53 overexpression.

A number of risk factors for esophageal and gastric cancers have emerged, yet little is known whether risk factors map to molecular tumor markers such as overexpression of the tumor suppressor TP53. Using a US multicenter, population-based case-control study (170 cases of esophageal adenocarcinomas, 147 gastric cardia adenocarcinomas, 220 non-cardia gastric adenocarcinomas, and 112 esophageal squamous cell carcinomas), we examined whether the risk associated with cigarette smoking, body mass index (BMI), gastroesophageal reflux disease (GERD), and non-steroidal anti-inflammatory drug (NSAID) use varied by P53 overexpression. We defined P53 overexpression through immunohistochemistry of paraffin-embedded tumor tissues, using cutpoints based on percent of cells positive. Polytomous logistic regression was used to assess differences between each case group (defined by tumor subtype and P53 expression) and the control group by risk factors. The proportion of cases overexpressing P53 by tumor subtype was 72% for esophageal adenocarcinoma, 69% for gastric cardia adenocarcinoma, 52% for non-cardia gastric adenocarcinoma, and 67% for esophageal squamous cell carcinoma. For most tumor subtypes, we found little difference in risk factors by tumor P53 overexpression. For non-cardia gastric cancer however, an association with cigarette smoking was suggested for tumors that do not overexpress P53, whereas larger BMI was related to adenocarcinomas that overexpress P53 versus no overexpression. Overall, this study did not find a clear relationship between P53 protein overexpression and the known risk factors for subtypes of esophageal and gastric cancers. Further research on these tumors is needed to identify molecular markers associated with variations in the risk factor profiles.

Chance favours only the prepared mind: Incubation and the delayed effects of peer collaboration.

Research has shown that the beneficial effects of peer collaboration are not always apparent until some time has elapsed. Such delayed effects are not readily incorporated in current models of collaborative learning, but because they constitute incubation effects in the psychological sense of the term, they should in principle be consistent with cognitive accounts of how incubation occurs. Accordingly, the paper reports three studies which test whether, in accordance with cognitive models of incubation, the delayed effects of peer collaboration could result from: (a) the breaking over time of unhelpful mental sets, (b) the engagement in post-collaborative reflective appraisal, and (c) the experience of subsequent events that, thanks to collaboration, can be used productively. The studies involved 9- to 12-year-old children working on the factors relevant to floating and sinking. The results provide no evidence for the relevance of set breaking or reflective appraisal, but suggest strongly that peer collaboration can 'prime' children to make good use of subsequent input. It is argued that in addition to clarifying how the delayed effects occur and applying incubation models in a novel context, the results flag up issues that are common to collaborative and cognitive theory, and that neither address adequately.

African-American/White differences in breast carcinoma: p53 alterations and other tumor characteristics.

BACKGROUND: Despite mounting evidence that breast tumors in African-American (AA) women are more aggressive compared with breast tumors in white (W) women, little is known regarding racial/ethnic differences in genetic alterations that may be of prognostic importance. METHODS: In this population-based cohort of 322 AA women (45%) and W women (55%) who were diagnosed with breast carcinoma between 1987-1989, the authors evaluated available archived tumor tissue (n = 247 samples) for racial differences in selected genetic alterations and other prognostic indicators. Tumor characteristics were assessed by immunohistochemistry and/or expert review. RESULTS: Alterations in p53 were significantly more common in AA women compared with W women (odds ratio, 4.00; 95% confidence interval, 1.77-9.01) and remained statistically significant in models that were adjusted for disease stage at diagnosis, according to American Joint Committee on Cancer (AJCC) criteria, and for other prognostic indicators. No racial difference with regard to HER-2/neu status was observed, but alterations in c-met were more common in AA women once the model was adjusted for negative confounders (not significant). Among other tumor characteristics, significant findings included later AJCC stage and higher histologic and nuclear grade tumors in AA women. In addition, the burden of aggressive tumor characteristics was greater in AA women because they were more likely to be at high risk on multiple factors (e.g., both high histologic grade and high nuclear grade [P = 0.03] and negative status for both estrogen receptors and progesterone receptors [P = 0.01]). CONCLUSIONS: Data from this population-based cohort confirmed that breast tumors in AA women most likely are more aggressive compared with breast tumors in W women and offer new evidence for possible racial/ethnic differences with regard to p53 alterations.

The countering of overgeneralization.

Commenting on Goldberg's (1995) 'construction grammar', Tomasello (1998) proposes a model of language acquisition in which children move from highly specific utterance-event pairings to abstract, verb-general structures. Despite their many strengths, models of this kind predict considerably more overgeneralization of the argument structures of verbs than seems to occur. In recognition of this, the paper explains (and supports with data from a previously unpublished study of 44 children aged 2;0 to 4;4) how processes which are side effects of the emergence of the verb form class could counter the overgeneralizing tendencies. It is argued that these processes are consistent not just with the model proposed by Tomasello but also (in large part) with the grammatical theory developed by Goldberg.

Active signaling by HER-2/neu in a subpopulation of HER-2/neu-overexpressing ductal carcinoma in situ: clinicopathological correlates.

HER-2/neu overexpression occurs in a proportion of invasive breast carcinomasand is an adverse prognostic indicator, although its apparent strength as a prognostic indicator varies in different studies. Paradoxically, HER-2/neu is overexpressed with particularly high frequency in ductal carcinoma in situ (DCIS). We have hypothesized and presented supporting data that HER-2/neu is actively signaling in a subset of the tumors in which it is overexpressed. We use an activation state-dependent anti-HER-2/neu monoclonal antibody (PN2A) produced in our laboratory to study this paradigm immunohistochemically. In this report, we analyze the characteristics of 219 cases of DCIS with respect to HER-2/neu expression and activation state. We find that 58% of cases of DCIS with overexpression have the receptor in the activated state, a substantially greater proportion than we have previously noted for invasive carcinomas. Although HER-2/neu overexpression in general was inversely correlated with hormone receptor expression, cases with activated HER-2/neu had the lowest hormone receptor positivity rate. Statistically significant correlations with activated HER-2/neu were not noted for tumor size, presence of calcifications, necrosis or fibrosis, or indicators of angiogenesis. These results suggest that examination of activated HER-2/neu status may better reflect the biology of a tumor than overall determination of HER-2/neu levels. Our finding that active signaling by HER-2/neu, as detected by this assay, is more frequent in DCIS than previously noted for invasive carcinoma implicates signaling by HER-2/neu as having a critical role in the early stages of breast tumorigenesis.