Age deficits in the control of prepotent responses: evidence for an inhibitory decline

Older adults have more difficulty than younger adults appropriately directing their behavior when the required response is in competition with a prepotent response. The authors varied the difficulty of inhibiting a prepotent eye movement response by varying the response cue (peripheral onset or central arrow). The response cue manipulation did not affect prosaccade accuracy and latency for either age group and did not affect younger adults' antisaccades. Older adults' antisaccades were slower in the peripheral cue condition than in the central arrow condition. These findings are taken as support for the inhibitory deficit hypothesis of aging (L. Hasher, R. T. Zacks, & C. P. May, 1999).     

The effects of behavioral history on response acquisition with immediate and delayed reinforcement

Effects of prior exposure to the experimental chamber with levers present or absent and variable-time (VT) 60-s water deliveries arranged during one, five, or no 1-hr sessions were examined in rats during a 6-hr response-acquisition session in which presses on one lever produced water delivery immediately or after a 15-s resetting delay, and presses on the other lever canceled scheduled water deliveries. Response acquisition was (a) slower to occur when water deliveries were delayed, (b) most consistent in groups that had received five VT sessions, and (c) impaired by the presence of levers only when there had been five VT sessions and water deliveries were delayed during the acquisition session.     

The Galileo bias: a naive conceptual belief that influences people's perceptions and performance in a ball-dropping task

This research introduces a new naive physics belief, the Galileo bias, whereby people ignore air resistance and falsely believe that all objects fall at the same rate. Survey results revealed that this bias is held by many and is surprisingly strongest for those with formal physics instruction. In 2 experiments, 98 participants dropped ball pairs varying in volume and/or mass from a height of 10 m, with the goal of both balls hitting the ground simultaneously. The majority of participants in both experiments adopted a single strategy consistent with the Galileo bias, showing no improvement across trials. Yet, for participants reporting intentions of dropping both balls at the same time, the differences between release points were significantly greater than 0 ms. These findings support separate but interacting cognition and perception-action systems.     

“One-thousand<Emphasis Type="Italic">one</Emphasis> … one-thousand<Emphasis Type="Italic">two</Emphasis> …”: Chronometric counting violates the scalar property in interval timing

Medical College of Wisconsin, Milwaukee, Wisconsin Weber’s law applied to interval timing is called thescalar property. A hallmark of timing in the secondsto-minutes range, the scalar property is characterized by proportionality between the standard deviation of a response distribution and the duration being timed. In this temporal reproduction study, we assessed whether the scalar property was upheld when participants chronometrically counted three visually presented durations (8, 16, and 24 sec) as compared with explicitly timing durations without counting. Accuracy for timing and accuracy for counting were similar. However, whereas timing variability showed the scalar property, counting variability did not. Counting variability across intervals was accurately modeled by summing a random variable representing an individual count. A second experiment replicated the first and demonstrated that task differences were not due to presentation order or practice effects. The distinct psychophysical properties of counting and timing behaviors argue for greater attention to participant strategies in timing studies.     

The association of irritability and impulsivity with suicidal ideation among 15- to 20-year-old males

Information on the association of impulsivity and measures of aggression with suicidal ideation in adolescents and young adults is limited. Data were gathered from a community sample of 625 adolescent and young adult males. Analyses were based on multivariate generalized estimating equations. Impulsivity and irritability were associated strongly with suicidal ideation after accounting for alcohol dependence and other aggression-related constructs including psychopathy. Given that irritable, impulsive adolescent males appear to contemplate suicidal behavior, their heightened suicide risk may be anticipated and mitigated.     

In Search of a Conceptualization of Multiple Sclerosis: A Historical Perspective

A thorough understanding of Multiple Sclerosis (MS) is necessary to offer individuals informed options for treatment and planning. To assist in this quest, the following historical analysis examined how MS has been conceived from the 14th century through the early 20th century. Primary sources were consulted whenever possible, and many of the original archival materials were accessed by the first author (MB) during an on-site visit to the Rare Book Room of the New York Academy of Medicine. There is a striking similarity between how MS symptoms have presented throughout history compared with the 21st century. Sensorimotor and cognitive sequelae have been observed in patients since the 1800s. Cognitive symptoms were acknowledged in the 1800s, but disregarded in the early 1900s and were not given recognition again until the latter part of the 20th century. If conceptualizations of MS are inaccurate, patients will not be served well. In contrast to the shared symptomatology across time, early conceptualizations of etiology and treatment choices differed dramatically from today, a genuine reflection of the times in which they were created.     

Psychopathology of incarcerated sex offenders

The psychopathology and particularly the personality disorders of sex offenders were compared to general inmates of the Colorado Department of Corrections. Using the MCMI-III (Millon, 1994, 1997), sex offenders in general were found to have more varied types of personalities than general population inmates. Specifically, they were more schizoid, avoidant, depressive, dependent, self-defeating, and schizotypal. General population inmates had the more classically criminal personality characteristics of antisocial, narcissistic, and sadistic. Multivariate analysis showed the Dependent, Narcissistic, Antisocial, and Schizotypal scales to be the most differentiating. Sex offenders were also found to have more affective psychopathology such as anxiety, dysthymia, PTSD, and major depression. A similar trend was found when comparing child molesters to rapists. The child molesters were more neurotic, affective, and socially impaired than the rapists. Multivariate analysis showed the Dependent scale to be the most important in differentiating these two types of sex offenders.     

Measuring Memory Span

This study, conducted on a sample of 403 adult subjects, set out to explore the relationships between measures of digit span (forward and reversed), motor and spatial span, and their dependence on a broad range of measures of cognitive function. The results revealed that measures of digit span are closely related, as are measures of motor and spatial span, but these pairs of memory span measures are relatively independent of each other. Furthermore, reverse digit span, motor span, and spatial span appear to rely on what might be regarded as intellectual or executive cognitive functions. As such, the results provide little support for accounts of serial recall, which suggest that order and/or item information are more adequately modelled in a modality-independent form.     

THE UTILITY OF CURRICULUM-BASED MEASUREMENT FOR EVALUATING THE EFFECTS OF METHYLPHENIDATE ON ACADEMIC PERFORMANCE

Two case studies were conducted to investigate the utility of curriculum-based measurement of math and reading for evaluating the effects of methylphenidate on the academic performance of 2 students diagnosed with attention deficit hyperactivity disorder. Following baseline measurement, double-blind placebo-controlled procedures were employed to evaluate each student's response to three levels (5 mg, 10 mg, and 15 mg) of the medication. Results of the first study suggest that the curriculum-based measures were sensitive indicators of the student's response to medication. This finding was replicated in the second study. In the second study, when the student's follow-up dose of medication was based on trial-phase data, follow-up performance was improved compared to baseline performance. These case studies suggest that further research is warranted on the utility of curriculum-based measurements for monitoring and evaluating stimulant medication interventions with children with this disorder.