Psychology Commons^™

Bimanual Reaching Across The Hemispace: Which Hand Is Yoked To Which?, Gavin Buckingham, Gordon Binsted, David Carey

Gavin Buckingham

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries …

The Influence Of Competing Perceptual And Motor Priors In The Context Of The Size-Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

When lifting objects of identical mass but different sizes, people perceive the smaller objects as weighing more than the larger ones (the 'size-weight' illusion, SWI). While individual's grip and load force rates are rapidly scaled to the objects' actual mass, the magnitude of the force used to lift these SWI-inducing objects is rarely discussed. Here, we show that participants continue to apply a greater loading force to a large SWI-inducing cube than to a small SWI cube, lift after lift. These differences in load force persisted long after initial errors in grip and load force rates had been corrected. Interestingly, …

On The Number Of Trials Necessary For Stabilization Of Error-Related Brain Activity Across The Life Span, Jason Themanson, Matthew Pontifex, Mark Scudder, Michael Brown, Kevin O'Leary, Chien-Ting Wu, Charles Hillman

Jason R. Themanson, Ph.D

The minimum number of trials necessary to accurately characterize the error-related negativity (ERN) and the error positivity (Pe) across the life span was investigated using samples of preadolescent children, college-age young adults, and older adults. Event-related potentials and task performance were subsequently measured during a modified flanker task. Response-locked averages were created using sequentially increasing errors of commission in blocks of two. Findings indicated that across all age cohorts ERN and Pe were not significantly different relative to the within-participants grand average after six trials. Further, results indicated that the ERN and Pe exhibited excellent internal reliability in preadolescent children …

Gating Of Vibrotactile Detection During Visually Guided Bimanual Reaches, Gavin Buckingham, David Carey, Francisco Colino, John Degrosbois, Gordon Binsted

Gavin Buckingham

It is far more difficult to detect a small tactile stimulation on a finger that is moving compared to when it is static. This suppression of tactile information during motion, known as tactile gating, has been examined in some detail during single-joint movements. However, the existence and time course of this gating has yet to be examined during visually guided multi-joint reaches, where sensory feedback may be paramount. The current study demonstrated that neurologically intact humans are unable to detect a small vibratory stimulus on one of their index fingers during a bimanual reach toward visual targets. By parametrically altering …

The Biology Of Reality Testing - Implications For Cognitive Education, Neil Greenberg

Neil Greenberg

• This report explores the proposition that teaching effectiveness can be enhanced by accommodating the key differences between two complementary and deeply engrained modes of reality testing, each predominantly centered in different hemispheres of the brain. • (1) Correspondence involves “reality-testing” of a percept, the cerebral representation of an experience in the world. • (2) Coherence involves “textualizing”, that is, reality-testing of a percept by how easily it relates to previous and ongoing parallel and collateral experiences. • Confidence in the validity of any percept throughout development is related to the interplay of these key processes. • As organisms develop, …

Lifting Without Seeing: The Role Of Vision In Perceiving And Acting Upon The Size Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

BACKGROUND: Our expectations of an object's heaviness not only drive our fingertip forces, but also our perception of heaviness. This effect is highlighted by the classic size-weight illusion (SWI), where different-sized objects of identical mass feel different weights. Here, we examined whether these expectations are sufficient to induce the SWI in a single wooden cube when lifted without visual feedback, by varying the size of the object seen prior to the lift.

METHODOLOGY/PRINCIPAL FINDINGS: Participants, who believed that they were lifting the same object that they had just seen, reported that the weight of the single, standard-sized cube that they …

The Relation Of Aerobic Fitness To Neuroelectric Indices Of Cognitive And Motor Task Preparation, Jason Themanson, Keita Kamijo, Kevin O'Leary, Matthew Pontifex, Charles Hillman

Jason R. Themanson, Ph.D

The relation of aerobic fitness to task preparation was examined in a sample of young adults separated into higher- and lower-fit groups according to their maximal oxygen consumption. Participants performed a modified Sternberg working memory task under speed and accuracy instructions while measures of task performance and contingent negative variation (CNV) were collected. Analyses revealed no significant fitness differences between groups on task performance measures. However, frontal CNVamplitude was significantly larger for lower-fit participants compared to higher-fit participants during the speed instructions, an effect not found for the accuracy instructions. These results suggest that lower-fit individuals may rely to a …

Lifting Without Seeing: The Role Of Vision In Perceiving And Acting Upon The Size‐Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

Our expectations of an object’s heaviness not only drive our fingertip forces, but also our perception of heaviness. This effect is highlighted by the classic size-weight illusion (SWI), where different‐sized objects of identical mass feel different weights (Charpentier, 1891) long after any initial errors in the application of fingertip forces have been corrected (Flanagan & Beltzner, 2000).

Here, we examined whether our expectations about the weight of an upcoming lift are sufficient to induce the SWI in a single wooden cube when lifted without visual feedback, by varying the size of the object seen prior to the lift during a …

Laterality, Perception, And Action During The Size-Weight Illusion, Gavin Buckingham, Nathalie Ranger, Melvyn Goodale

Gavin Buckingham

In the classic size-weight illusion (SWI), a small object will feel heavier than an larger object of equal weight (Charpentier, 1891). Individuals continue to perceive this illusory difference in weight long after their gripping and lifting forces have scaled to the actual, identical, mass of the illusion-inducing stimuli (Flanagan & Beltzner, 2000).

The independence of our weight perception and fingertip force application has only been quantified in the right hand of right-handers. The immunity to this perceptual illusion may be affected by manual asymmetries (e.g., Gonzalez, Ganel & Goodale, 2006).

We examined perception of heaviness and fingertip force scaling in …