Adult visual choice-reaction time, age, sex and preparedness: A test of Welford's problem in a large population sample

The relationship between age, sex and visual three-choice reaction time was investigated with a representative sample of adult subjects who participated in a large health survey in Finland (the Mini-Finland Survey). Subjects' age varied from 30 to 79 years. Reaction time increased reliably with increasing age. Men were faster than women across all age levels. The shortest of the irregularly presented inter-stimulus intervals (ISI) slowed down the performance of elderly subjects in particular. This suggests that they had more difficulty than younger subjects in getting prepared for an uncertain event. They also committed most errors at the longest ISI. This was interpreted as a result of their relative inability to maintain the optimum level of preparation. On the whole, men displayed a higher error rate than women, which suggests that the observed male superiority is at least in part due to response strategies. The importance for aging research of sampling the subjects and task types is briefly discussed.     

Noise and visual choice-reaction time: A large-scale population survey

The impact of a 80 dB(A) intermittent broadband noise on a three-choice visual reaction time (RT) task was investigated. There were 2661 subjects who represented the healthy Finnish population from the age of 30 to 79 years. Noise slowed down the response speed highly significantly but the main effect was negligible in the psychological sense (513 vs. 506 msec). The performance of the elderly was more affected than that of the young. Slow responders did not show any detrimental effect of noise irrespective of whether or not they committed errors. The results are discussed in terms of person-induced ways to perform and cope under a mild stress.     

Neuropsychological subgroups of adolescents with conduct disorder

Närhi, V., Lehto‐Salo, P., Ahonen, T. & Marttunen, M. (2010). Neuropsychological subgroups of adolescents with conduct disorder. Scandinavian Journal of Psychology, 51, 278–284. In group‐level studies adolescents with conduct disorder (CD) have been found to have deficiencies in verbal and executive functions. Teichner and Golden (2000) addressed the neuropsychological heterogeneity of CD, and hypothesized the existence of six neuropsychologically different subgroups. We used that theoretical basis to identify subgroups among 77 adolescents with CD and 48 controls. Among subjects with CD we identified subjects with no, diffuse, verbal and executive function deficits, but none with specific memory or visuo‐spatial deficits. In total, neuropsychological deficits altogether were more common among subjects with CD relative to controls, as were specific verbal deficits. Subgroups did not differ in gender distribution, comorbidity of psychiatric disorders, type or severity of CD, or number of psychosocial risk factors. Among subjects with CD, learning disabilities were common. CD is neuropsychologically a heterogeneous disorder, and neuropsychological deficits should be taken into account in assessing and planning interventions for adolescents with CD.