Developing symbolic capacity one step at a time

The present research examines the ability of children as young as 4 years to use models in tasks that require scaling of distance along a single dimension. In Experiment 1, we found that tasks involving models are similar in difficulty to those involving maps that we studied earlier (Huttenlocher, J., Newcombe, N., & Vasilyeva, M. (1999). Spatial scaling in young children. Psychological Science, 10, 393-398). In Experiment 2, we found that retrieval tasks, where children indicate the location of a hidden object in an actual space are substantially more difficult than placement tasks, where children put a visible object in a particular location in an actual space. We discuss possible implications of the differential difficulty of retrieval and placement tasks for the understanding of symbolic development.     

Child Perceptions of Parental Care and Overprotection in Children with Cancer and Healthy Children

The primary aims of this study were to: (a) examine child perceptions of overprotection; and (b) explore how these perceptions relate to child health and adjustment. Children with a prior diagnosis of cancer (n = 205) and children without a history of serious illness (n = 76) reported on parental overprotective and caring behaviors. Children with cancer were recruited from one of four strata based on the elapsed time since their cancer diagnosis (1–6 months; 6–24 months; 2–5 years; >5 years) Children also reported on symptoms of depression, anxiety, and posttraumatic stress. Children with cancer did not differ from healthy children in their perceptions of parental care or overprotection. Child distress was more strongly related to perceptions of care and overprotection than child’s health status. Children with cancer do not report their parents approach to care and protection differently than children without a cancer history. These findings mirror prior research examining parental perceptions of overprotection and suggest that, despite the challenges of parenting a child with serious illness, parental protection is not significantly altered.     

Copernicus,the orbs,and the equant

I argue that Copernicus accepted the reality of celestial spheres on the grounds that the equant problem is unintelligible except as a problem about real spheres. The same considerations point to a number of generally unnoticed liabilities of Copernican astronomy, especially gaps between the spheres, and the failure of some spheres to obey the principle that their natural motion is to rotate. These difficulties may be additional reasons for Copernicus's reluctance to publish, and also stand in the way of strict realism as applied to De Revolutionibus, although a realistic astronomy may be envisioned as a goal for Copernicus's research program.     

Time stamp in conditioned place avoidance can be set to different circadian phases

We have reported that the expression of conditioned place avoidance (CPA) in the golden hamster is regulated in a circadian pattern such that the preference is exhibited strongly at the circadian time of prior training but not at other circadian times [Cain, S. W., Chou, T., & Ralph, M. R. (2004a). Circadian modulation of performance on an aversion-based place learning task in hamsters. Behavioural Brain Research, 150(1–2), 201–205]. In that study, animals that were trained at a specific circadian time to discriminate between a “safe” context and one paired with foot shock, showed strong avoidance of the paired context at 24 and 48 h following the last training session, and showed no avoidance at 32 and 40 h following training. In the present study, we hypothesized that this “time stamp” effect is settable to any circadian phase. This was tested by training animals at one of two times of day (ZT13 or ZT4) and testing whether a time stamp would be observed, with avoidance occurring only when training and testing times match. Results confirmed our hypothesis, suggesting that the time stamp in the performance of learned tasks can be set to any circadian phase. Such an ability may allow animals in nature to predict the recurrence of 24 h events, regardless of the time of day the event was encountered.     

An empirical assessment of generational differences in basic human values

This study assessed generational differences in human values as measured by the Schwartz Value Survey. It was proposed that the two most recent generations, Millennials and Generation Xers, would value Self-enhancement and Openness to Change more than the two older generations, Baby Boomers and Matures, while the two older generations would value Self-transcendence and Conservation more. The hypotheses were tested with a combined sample of Canadian knowledge workers and undergraduate business students (N = 1,194). Two hypotheses were largely supported, although an unexpectedly large difference was observed between Millennials and Generation Xers with respect to Openness to Change and Self-enhancement. The findings suggest that generation is a useful variable in examining differences in social values.     

Testing the developmental distinctiveness of male proactive and reactive aggression with a nested longitudinal experimental intervention

An experimental preventive intervention nested into a longitudinal study was used to test the developmental distinctiveness of proactive and reactive aggression. The randomized multimodal preventive intervention targeted a subsample of boys rated disruptive by their teachers. These boys were initially part of a sample of 895 boys, followed from kindergarten to 17 years of age. Semiparametric analyses of developmental trajectories for self‐reported proactive and reactive aggression (between 13 and 17 years of age) indicated three trajectories for each type of aggression that varied in size and shape (Low, Moderate, and High Peaking). Intent‐to‐treat comparisons between the boys in the prevention group and the control group confirmed that the preventive intervention between 7 and 9 years of age, which included parenting skills and social skills training, could impact the development of reactive more than proactive aggression. The intervention effect identified in reactive aggression was related to a reduction in self‐reported coercive parenting. The importance of these results for the distinction between subtypes of aggressive behaviors and the value of longitudinal‐experimental studies from early childhood onward is discussed. Aggr. Behav. 36:127–140, 2010. © 2010 Wiley‐Liss, Inc.