Recruitment modeling applied to longitudinal studies of group differences in intelligence

In longitudinal studies data is collected in a series of waves. Each wave after the first suffers from attrition. Therefore it can be difficult to discriminate between changes in sample parameters due to a longitudinal process (e.g. ageing) and changes due to attrition. The problem is particularly vexing if one of the purposes is to compare differences between two or more groups over time, because there may be differential attrition across groups. We refer to this as a recruitment problem, because the sample studied in any wave after the first can be thought of as having been recruited from a preceding wave. We present a mathematical model of the recruitment process. We then apply it to two large longitudinal studies, the British Cohort Survey 1970 and the National Child Development Study (1958), to demonstrate how we can identify effects expected from recruitment alone. As an illustration we show that differential recruitment would predict increasing differences between estimates of men's and women's intelligence as the studied sample ages.     

Brief cognitive-behavioral internet therapy for irritable bowel syndrome

While cognitive-behavioral therapy for IBS is quite effective, the limited availability of competent therapists and lack of access to treatment remain problematic. This paper reports on a small, randomized, controlled trial of a five week internet based cognitive-behavioral intervention for IBS with limited therapist feedback via e-mail. Fifty-four IBS patients were recruited via the internet and randomly assigned to either immediate treatment or a wait-list control group. Thirty-one subjects completed the post-treatment assessment. 77% of treatment completers also completed a 3-month follow-up assessment. Treatment completers experienced statistically and clinically significant declines in IBS symptoms and improvements in quality of life. Those gains were substantially maintained at follow-up. Treatment efficacy was partially mediated by reductions in the tendency to catastrophize the social and occupational implications of symptoms, suggesting that catastrophizing may be an important target for treatment.     

Pharmacological dissociation of trace and long-delay fear conditioning in young rats

In most studies comparing trace and delay conditioning, CS duration is kept constant across training conditions but the interstimulus interval (ISI), the time from CS onset to US onset, is confounded. In the infrequently used long-delay condition, however, ISI is kept constant across the trace and delay conditions but CS duration varies. A recent study reported that trace and long-delay fear conditioning have the same developmental trajectory, with both emerging later in development than standard-delay conditioning (). Past studies have shown that trace conditioning is mediated by the cholinergic system; given the parallel developmental emergence of trace and long-delay conditioning, the present study examined whether the cholinergic system also mediates long-delay conditioning. Two experiments, both involving Sprague-Dawley-derived rats and using freezing as a measure of learned fear, showed that the cholinergic system is critically involved in trace conditioning but is not involved in long-delay conditioning. Specifically, pre-training injections of the muscarinic receptor antagonist scopolamine impaired acquisition of a CS-US association in 32-day-old rats trained with a trace procedure but had no effect on rats this age trained with a long-delay procedure (Experiment 1). Similarly, pre-training injections of physostigmine, a cholinesterase inhibitor, enhanced acquisition of trace conditioning in 25-day-old rats but had no effect on long-delay conditioning in rats this age (Experiment 2). Taken together, the results indicate that despite the similarities between trace and long-delay conditioning in terms of developmental emergence and level of conditioned responding, they are mediated by different physiological systems.     

Revised norms for the Lollipop Test for children ages 42 to 65 months

Lollipop Test scores were acquired for 1,402 preschoolers in southwestern Indiana. Means and standard deviations for both boys and girls by 6-mo. intervals from the ages of 42 through 65 months showed scores increased significantly across ages, with girls scoring significantly higher than boys in all age groups. Current mean scores are similar to those published in 1988 for boys and slightly higher for girls.     

The effect of study modality on false recognition

A number of previous studies have shown that false recognition of critical items in the Deese/Roediger-McDermott paradigm is reduced when study items are presented visually rather than auditorily; however, this effect has not been uniformly demonstrated. We investigated three potential boundary conditions of the effect of study modality in false recognition. Experiments 1 and 2 showed no reduction in false recognition following visual study presentation when the yes-no recognition test was not preceded by a recall test. Experiment 3 showed that visual study presentation can reduce false recognition without a preceding recall test, if the recognition test uses remember-know instructions. The order of the recognition test items did not influence the effect of visual study presentation on false recognition in Experiment 1. In general, the data imply that distinctive processing at study can reduce false memory in recognition if the test demands draw attention to the dimension of distinctive processing.     

The Emerging Church and its discontents

The so‐called ‘Emerging Church’ constitutes a growing, if ill‐defined, Christian movement that has surfaced in North America, Europe, Australia, New Zealand and other nations of the Western world. The movement constitutes a theological and organisational critique of the conventional Christian Church, while offering a new mode of evangelism. This paper commences by briefly exploring the major attributes of the Emerging Church. It argues that although the movement can be understood as a means by which a distinct Christianity constituency has attempted to forge a juxtaposition with contemporary culture, the arrival of the movement has spurred widespread debate and produced a complex discourse indicative of the arrival of post‐modernity. The paper considers the controversy, and even acrimony, evident in the broad world of evangelicalism, in particular conservative evangelicalism, that the Emerging Church has generated.