Response Timing Variability

A detailed kinematic and electromyographic (EMG) analysis of single degree of freedom timing responses is reported to (a) determine the coherence of kinematic and EMG variability to the reduced timing error variability exhibited with amplitude increments within a given criterion movement time and (b) understand the temporal organization of various movement parameters in simple responses. The data reveal that the variability of kinematic (time to peak acceleration, duration of acceleration phase, time to peak deceleration) and EMG (duration of agonist burst, duration of antagonist burst, time to antagonist burst) timing parameters decreased with increments of average velocity in a manner consistent with the variable timing error. In addition, the coefficient of variation for peak acceleration, peak deceleration, and integrated EMG of the agonist burst followed the same trend. Increasing average movement velocity also led to decreases in premotor and motor reaction times. Overall, the findings suggest a strong coherence between the variability of response outcome, kinematic, and EMG parameters.     

Reading Comprehension: Effects of Individualized,Integrated Language Arts as a Reading Approach with Struggling Readers

This study examined the effects of individualized, integrated language arts as a reading approach on struggling readers' comprehension scores obtained from oral narrative, silent narrative, and silent expository passages at three levels: below-grade, on-grade, and above-grade levels. Students (N = 93) in grades four through eight, who were reading below grade level, participated in the study. Treatment group students (n = 51) received individualized, integrated language arts as a reading approach once a week in place of basal reading instruction. Comparison group students (n = 42) received basal reading instruction for the duration of the study. Multivariate analysis of covariance was used to analyze posttest Analytical Reading Inventory (ARI) comprehension scores. Several statistically significant (p < .001) differences in comprehension performance were found for on-grade-level scores and for above-grade-level scores, but few differences were found between treatment and comparison groups on below-grade-level scores. All statistically significant differences favored students in the treatment group. The findings of the study strongly suggest that the use of individualized, integrated language arts as a method for teaching reading is an effective approach for improving the reading comprehension performance of struggling readers.     

Recognising what you like: Examining the relation between the mere-exposure effect and recognition

The perceptual fluency/attributional model of the mere-exposure effect proposed by R. F. Bornstein and P. D'Agostino (1992) predicts that when recognition of a previously presented stimulus is above chance, feelings of fluency associated with that stimulus are discounted and thus the amount of fluency (mis)attributed to liking is reduced. This correction process results in smaller mere-exposure effects for supraliminal stimuli than for “subliminal” stimuli because when recognition is below chance participants are unaware of the source of fluency and they do not engage in correction. We tested this prediction in three experiments by presenting photographs of faces (Experiments 1 and 2) and polygons (Experiment 3) at varying exposure frequencies for 40 ms and 400 ms durations. Contrary to the prediction of the model, a significant mere-exposure effect was only found when recognition performance was at its highest level. Furthermore, across the three experiments liking and recognition were positively correlated.     

A digital system for recording startle,responses in small animals

An easily constructed, isometric startle-recording system is described. The animal enclosure is attached to a plywood board-which, in ten, is mounted in a “springboard” arrangement. Movement is detected by a phonocartridge mounted beneath the chamber, and a digital record of this movement is obtained through the use of a voltage-to-frequency converter. A brief experiment in which the system was used to assess the rat’s reaction to electric footshock is also presented.     

Movement Speed and Accuracy in Space and Time: The Complementarity of Error Distributions

Movement speed-accuracy trade-off is a function of the space-time constraints of the task. We investigated the space-time account of Hancock and Newell (1985) and the hypothesis of complementarity between the four moments of the error distribution in space and time. Twelve participants performed 15 conditions in a line drawing task composed of different spatial (10, 20, and 30 cm) and temporal (250 to 2,500 ms) criteria. The results showed that all moments of distributions changed systematically between conditions but there were some departures from the Hancock and Newell predictions. In contrast, individual analysis revealed the complementarity of the spatial and temporal error including a trade-off between the four moments of error. These findings support a complementary space-time account of movement speed and accuracy.     

Perceptual Learning of Tooling Affordances of a Jointed Object via Dynamic Touch

We investigated whether perceptual learning via dynamic touch can facilitate the discovery of tooling affordances. Twelve blindfolded participants manipulated two structurally identical aluminum objects consisting of a blade and a shaft; one object was seven and a half times heavier than and twice as large as the other object. Flexions/extensions at two joints in the shaft changed the configuration and functionality of each object. A rigid shaft (one of four possible configurations) rendered each object a functional hoe. The number of changes in the configuration produced prior to determining that the grasped object had been rendered a functional hoe greatly exceeded the number of possible configurations and declined with experience, whereas the rate of change in configuration increased with experience. Inertial properties specifically support perception via dynamic touch and explained the observed differences in actions with the two objects. These findings demonstrate that perceptual learning via dynamic touch can facilitate the discovery of tooling affordances.     

Learning in the brain–computer interface: insights about degrees of freedom and degeneracy from a landscape model of motor learning

In this paper, we examine the role of degrees of freedom and their degeneracy in learning in the brain–computer interface paradigm. Though the traditional notion of degrees of freedom in motor learning gave emphasis to muscle and joint activity, the broader concept of dimensions of behavior is relevant to brain–computer interface learning where there is no muscle activity. The role of degeneracy in the dimensions of brain activity is proposed to enhance learning through robustness to stability loss and adaptability in the search for new stable states. Principles for the application of augmented information for learning to coordinate and control the degenerate degrees of freedom in the brain–computer interface are outlined.     

Where to look first for an explanation of induction with uncertain categories

Recent research has examined how people predict unobserved features of an object when its category membership is ambiguous. The debate has focused on whether predictions are based solely on information from the most likely category, or whether information from other possible categories is also used. In the present experiment, we compared these category-based approaches with feature conjunction reasoning, where predictions are based on a comparison among exemplars (rather than categories) that share features with a target object. Reasoning strategies were assessed by examining patterns of feature prediction and by using an eye gaze measure of attention during induction. The main findings were (1) the majority of participants used feature conjunction rather than categorical strategies, (2) people predominantly gazed at the exemplars that were most similar to the target object, and (3) although people gazed most at the most probable category to which an object could belong, they also attended to other plausible category alternatives during induction. These findings question the extent to which category-based reasoning is used for induction when category membership is uncertain.