In Barkley's (1997a, 1997b) model of attention-deficit/hyperactivity disorder (ADHD), he proposes that working memory deficits resulting from ADHD may cause impairments in reading comprehension. ADHD has been associated with poorer processing speed and working memory as well as academic underachievement in some studies. However, more research is…

The placebo effect is any outcome that is not attributed to a specific treatment but rather to an individual's mindset (Benson & Friedman, 1996). This phenomenon can extend beyond its typical use in pharmaceutical drugs to involve aspects of everyday life, such as the effect of sleep on cognitive functioning. In 2 studies examining whether…

Various experiments demonstrated that the difficulty level of several performance-type intelligence test tasks is determined directly by stimulus and task variables that vary the information to be processed. The implications of these findings for intelligence and the problems of an experimental approach to the measurement of intelligence are…

Results from a representative sample of 123 adults in the United Kingdom tested with the Wechsler Adult Intelligence Scale-Revised and a test of word identification time are in line with previous findings that speed of information processing is significantly related to performance IQ but not to verbal IQ. (SLD)