Reaction time inconsistency in a spatial stroop task: age-related differences through childhood and adulthood.

Age-related differences in inconsistency of reaction time (RT) across the life span were examined on a task with differing levels of demand on executive control. A total of 546 participants, aged 5 to 76 years, completed a spatial Stroop task that permitted observations under three conditions (congruent, incongruent, and neutral) according to the correspondence between the required response (based on stimulus direction) and stimulus location. An interference effect was observed across all ages. Analyses of neutral condition data replicated previous research demonstrating RT inconsistency follows a U-shaped developmental curve across the life span. The relationship between age and inconsistency, however, depended on condition: inconsistency in the congruent condition was higher than inconsistency in both the neutral and incongruent conditions across middle-aged groups. Reaction time inconsistency may reflect processing efficiency that is maximal in young adulthood and may also be sensitive to fluctuations in performance that reflect momentarily highly efficient responding.

Reaction time performance in adolescents with attention deficit/hyperactivity disorder: evidence of inconsistency in the fast and slow portions of the RT distribution.

Inconsistency across trials of 2-choice reaction time (RT) data was analyzed in 72 adolescents (age 12-17 years) within 4 groups differentiated by the presence or absence of attention deficit/hyperactivity disorder (ADHD) and reading difficulties (RD). ADHD participants were more inconsistent (across all trials, and in the slow portion of the RT distribution) than controls, but only when RD was present. Within the fast portion of the RT distribution, ADHD participants were more inconsistent than controls regardless of RD. The results highlight the importance of fluctuations in cognitive performance in ADHD and suggest that there may be independent sources of variation in inconsistency affecting the fast and slow portions of the RT distribution.

Inconsistency in reaction time across the life span.

Inconsistency in latency across trials of 2-choice reaction time data was analyzed in 273 participants ranging in age from 6 to 81 years. A U-shaped curve defined the relationship between age and inconsistency, with increases in age associated with lower inconsistency throughout childhood and higher inconsistency throughout adulthood. Differences in inconsistency were independent of practice, fatigue, and age-related differences in mean level of performance. Evidence for general and specific variability-producing processes was found in those aged less than 21 years, whereas only a specific process, such as attentional blocks, was evident for those 21 years and older. The findings highlight the importance of considering moment-to-moment changes in performance in psychological research.

Detecting malingering: a survey of experts' practices.

A survey addressing practices of 'expert' neuropsychologists in handling financial compensation claim or personal injury litigation cases was carried out. Potential participants were identified by publication history. Responses were obtained from 24 out of the 39 neuropsychologists who were surveyed. Approximately 79% of the respondents reported using at least one specialized technique for detecting malingering in every litigant assessment. Half stated that they always give specialized tests at the beginning of the assessment. The Rey 15-Item test and the Test of Memory Malingering were the most frequently reported measures. Respondents also reported frequent use of 'malingering' indexes from standard neuropsychological tests. Reported base-rates varied, but the majority of respondents indicated that at least 10% of the litigants they assessed in the last year were definitely malingering. Respondents were split on the practice of routinely giving warnings at the outset of assessments that suboptimal performance may be detected. However, when the client's motivational status was suspect, more than half (58.3%) altered their assessment routine at least on some occasions, by encouraging good effort (70.8%) or administering additional SVTs. A minority directly confronted or warned clients (25%), terminated the examination earlier than planned (16.6%), or contacted the referring attorney immediately (29.2%). Respondents almost always stated some opinion regarding indicators of invalidity in written reports (95%). However, 41.7% rarely used the term 'malingering' and 12.5% never used the term. Most respondents (>80%) instead stated that the test results are invalid, inconsistent with the severity of the injury or indicative of exaggeration.