The prediction of intelligence in preschool children using alternative models to regression

Statistical prediction of an outcome variable using multiple independent variables is a common practice in the social and behavioral sciences. For example, neuropsychologists are sometimes called upon to provide predictions of preinjury cognitive functioning for individuals who have suffered a traumatic brain injury. Typically, these predictions are made using standard multiple linear regression models with several demographic variables (e.g., gender, ethnicity, education level) as predictors. Prior research has shown conflicting evidence regarding the ability of such models to provide accurate predictions of outcome variables such as full-scale intelligence (FSIQ) test scores. The present study had two goals: (1) to demonstrate the utility of a set of alternative prediction methods that have been applied extensively in the natural sciences and business but have not been frequently explored in the social sciences and (2) to develop models that can be used to predict premorbid cognitive functioning in preschool children. Predictions of Stanford–Binet 5 FSIQ scores for preschool-aged children is used to compare the performance of a multiple regression model with several of these alternative methods. Results demonstrate that classification and regression treesprovided more accurate predictions of FSIQ scores than does the more traditional regression approach. Implications of these results are discussed.     

Visual illusions affect both movement planning and on-line control: a multiple cue position on bias and goal-directed action

Over the last decade, there has been an interest in the impact of visual illusions on the control of action. Much of this work has been motivated by Milner and Goodale's two visual system model of visual processing. This model is based on a hypothesized dissociation between cognitive judgments and the visual control of action. It holds that action is immune to the visual context that provides the basis for the illusion-induced bias associated with cognitive judgments. Recently, Glover has challenged this position and has suggested that movement planning, but not movement execution is susceptible to visual illusions. Research from our lab is inconsistent with both models of visual-motor processing. With respect to the planning and control model, kinematic evidence shows that the impact of an illusion on manual aiming increases as the limb approaches the target. For the Ebbinghaus illusion, this involved a decrease in the time after peak velocity to accommodate the 'perceived' size of the target. For the Müller-Lyer illusion, the influence of the figure's tails increased from peak velocity to the end of the movement. Although our findings contradict a strong version of the two visual systems hypothesis, we did find dissociations between perception and action in another experiment. In this Müller-Lyer study, perceptual decisions were influenced by misjudgment of extent, while action was influenced by misjudgment of target position. Overall, our findings are consistent with the idea that it is often necessary to use visual context to make adjustments to ongoing movements.     

The fluttering-heart illusion: a new hypothesis

The fluttering-heart illusion is a perceived lagging behind of a colour target on a background of a different colour when the two are oscillated together. It has been proposed that the illusion is caused by a differential in the perceptual latencies of different colours (Helmholtz 1867/1962), a differential in rod-cone latencies (von Kries 1896) and rod-cone interactions (von Grünau 1975, 1976 Vision Research 15 431-436, 437-440; 16 397-401; see list of references there). The purpose of this experiment was to assess the hypothesis that the fluttering-heart illusion is caused by a differential in the perceived velocities of chromatic and achromatic motion. To evaluate this hypothesis, we tested observers possessing normal colour vision and deuteranopes. The perceived delay of a chromatic target relative to an achromatic target was measured as a function of background cone contrast and target colour. For observers with normal colour vision, the perceived delay of the chromatic target is greater in the L-S than the L-M testing conditions. The reverse is observed in deuteranope observers. We suggest that this is caused by the absence of an L-M opponent mechanism contributing to chromatic motion in deuteranopes. Greater background cone contrasts tended to yield smaller perceived delays in both normal and deuteranope observers, indicating that greater chromatic modulation decreases the perceived delay of the colour target. These results support the hypothesis that the fluttering-heart illusion can be explained by a differential in the perceived velocities of chromatic and achromatic motion.     

When rock bottom rocks your world: Crisis of belief as a catalyst for change

An experience of severe difficulty can turn the world upside-down, causing individuals to question important beliefs with which they identify. This phenomenon, which we label as Crisis of Belief (COB), amalgamates the disparate conceptualizations of crisis that exist across several subdisciplines of psychology. Unlike existing ideas of crisis, COB distinguishes itself from stress or trauma alone, and is a clearly specified construct that lends itself to practical operationalization and study. Thus, COB addresses a key gap in literature and offers unique value for understanding how hardship that affects closely held beliefs can catalyze change. We conclude by describing the potential utility of COB as a predictor of both positive (e.g., life satisfaction) and negative (e.g., depression) outcomes and the pressing need for a validated measure.     

Timing relations in speech and the identification of voice-onset times: a stable perceptual boundary for voicing categories across speaking rates

This study shows that the ratio of voice onset time (VOT) to syllable duration for /t/ and /d/ presents distributions with a stable boundary across speaking rates and that this boundary constitutes a perceptual criterion by which listeners judge the category affiliation of VOT. In Experiment 1, best-fit regression lines for VOT ratios of intervocalic /t/ and /d/ against speaking rate had zero slopes, and there was an inferable boundary between the distributions. In Experiment 2, listeners' identifications of syllable-initial stops conformed to this boundary ratio. In Experiment 3, VOT was held constant, while VOT ratios were altered by modifying the duration of the following vowel. As VOT ratios exceeded the boundary estimated from the data of Experiment 1, listeners' identifications shifted from /d/ to /t/. Timing relations in speech production can determine the identification of voicing categories across speaking rates.     

Inhibitory control in mind and brain: an interactive race model of countermanding saccades

The stop-signal task has been used to study normal cognitive control and clinical dysfunction. Its utility is derived from a race model that accounts for performance and provides an estimate of the time it takes to stop a movement. This model posits a race between go and stop processes with stochastically independent finish times. However, neurophysiological studies demonstrate that the neural correlates of the go and stop processes produce movements through a network of interacting neurons. The juxtaposition of the computational model with the neural data exposes a paradox-how can a network of interacting units produce behavior that appears to be the outcome of an independent race? The authors report how a simple, competitive network can solve this paradox and provide an account of what is measured by stop-signal reaction time.     

An evaluation of matrix training to teach college students piano notes and rhythms

Twelve college students learned to tact the names of notes and rhythms and play them when presented with compound stimuli (visuals of notes and rhythms on a musical staff). In Experiment 1, we assessed generalization by presenting novel notes, rhythms, and compound stimuli not previously paired together. In the second experiment, we added a metronome that played at 60 beats per minute in all conditions for 3 out of 6 participants to ensure consistent tempo. Across both experiments, participants passed almost all posttests with the exception of tacting and playing in the presence of sound clips. Our data suggest that matrix training is an effective procedure to teach music skills to college students.     

Changes in ADHD Symptom Endorsement: Preschool to School Age

To investigate endorsement patterns among the 18 DSM-IV symptoms of ADHD in a longitudinal sample of children with and without ADHD (n?=?144), as assessed at ages 4-5, 5-6, and 6-7 years. Symptom endorsements and diagnoses were determined at all time-points via K-SADS-PL interview administered to parents and supplemented by teacher questionnaires and clinician observations. Changes in endorsement patterns over time for each of the 18 DSM-IV symptoms were ascertained. Several symptoms, particularly those of inattention, were infrequently endorsed and of apparently limited diagnostic utility at ages 4-5; hyperactive/impulsive symptoms were more frequently endorsed among young children with ADHD than were inattentive symptoms. However, by ages 6-7, inattention items were somewhat superior at discriminating ADHD from Non-ADHD children. Several DSM-IV and now DSM-V symptoms provide limited diagnostic differentiation prior to school-age, particularly those most commonly observed in the context of formal schooling. Consideration should be made in future iterations of the DSM that account for such developmental and contextual differences.