Pseudoneglect for the Bisection of Mental Number Lines

2009 ◽  
Vol 62 (5) ◽  
pp. 925-945 ◽  
Author(s):  
Andrea M. Loftus ◽  
Michael E. R. Nicholls ◽  
Jason B. Mattingley ◽  
Heidi L. Chapman ◽  
John L. Bradshaw
Keyword(s):  
Temporal Order ◽  
Spatial Configuration ◽  
Number Line ◽  
Task Demands ◽  
Spatial Neglect ◽  
Leftward Bias ◽  
Number Lines ◽  
Intact Brain ◽  
Logarithmic Scaling ◽  
The Right

Patients with unilateral neglect of the left side bisect physical lines to the right whereas individuals with an intact brain bisect lines slightly to the left (pseudoneglect). Similarly, for mental number lines, which are arranged in a left-to-right ascending sequence, neglect patients bisect to the right. This study determined whether individuals with an intact brain show pseudoneglect for mental number lines. In Experiment 1, participants were presented with visual number triplets (e.g., 16, 36, 55) and determined whether the numerical distance was greater on the left or right side of the inner number. Despite changing the spatial configuration of the stimuli, or their temporal order, the numerical length on the left was consistently overestimated. The fact that the bias was unaffected by physical stimulus changes demonstrates that the bias is based on a mental representation. The leftward bias was also observed for sets of negative numbers (Experiment 2)—demonstrating not only that the number line extends into negative space but also that the bias is not the result of an arithmetic distortion caused by logarithmic scaling. The leftward bias could be caused by a rounding-down effect. Using numbers that were prone to large or small rounding-down errors, Experiment 3 showed no effect of rounding down. The task demands were changed in Experiment 4 so that participants determined whether the inner number was the true arithmetic centre or not. Participants mistook inner numbers shifted to the left to be the true numerical centre—reflecting leftward overestimation. The task was applied to 3 patients with right parietal damage with severe, moderate, or no spatial neglect (Experiment 5). A rightward bias was observed, which depended on the severity of neglect symptoms. Together, the data demonstrate a reliable and robust leftward bias for mental number line bisection, which reverses in clinical neglect. The bias mirrors pseudoneglect for physical lines and most likely reflects an expansion of the space occupied by lower numbers on the left side of the line and a contraction of space for higher numbers located on the right.

Fixated in unfamiliar territory: Mapping estimates across typical and atypical number lines

2019 ◽  
Vol 73 (2) ◽  
pp. 279-294
Author(s):  
Sabrina Michelle Di Lonardo ◽  
Matthew G Huebner ◽  
Katherine Newman ◽  
Jo-Anne LeFevre
Keyword(s):  
Numerical Range ◽  
Number Line ◽  
Strategy Use ◽  
Reverse Direction ◽  
Tracking Data ◽  
Spatial Processes ◽  
Number Lines ◽  
Number Line Estimation ◽  
The Right ◽  
Typical Range

Adults ( N = 72) estimated the location of target numbers on number lines that varied in numerical range (i.e., typical range 0–10,000 or atypical range 0–7,000) and spatial orientation (i.e., the 0 endpoint on the left [traditional] or on the right [reversed]). Eye-tracking data were used to assess strategy use. Participants made meaningful first fixations on the line, with fixations occurring around the origin for low target numbers and around the midpoint and endpoint for high target numbers. On traditional direction number lines, participants used left-to-right scanning and showed a leftward bias; these effects were reduced for the reverse direction number lines. Participants made fixations around the midpoint for both ranges but were less accurate when estimating target numbers around the midpoint on the 7,000-range number line. Thus, participants are using the internal benchmark (i.e., midpoint) to guide estimates on atypical range number lines, but they have difficulty calculating the midpoint, leading to less accurate estimates. In summary, both range and direction influenced strategy use and accuracy, suggesting that both numerical and spatial processes influence number line estimation.

scholarly journals Hemispheric antagonism in visuo-spatial neglect: A case study

1996 ◽  
Vol 2 (5) ◽  
pp. 412-418 ◽  
Author(s):  
John C. Marshall ◽  
Peter W. Halligan
Keyword(s):  
Right Hemisphere ◽  
Task Demands ◽  
Line Bisection ◽  
Spatial Neglect ◽  
Perceptual Task ◽  
Left Hand ◽  
Right Hand ◽  
The Right ◽  
Line Bisection Task

AbstractWe report a case of severe visuo-spatial neglect consequent upon right-hemisphere stroke. At the time of testing, the patient had no visual field cut and no significant hemiparesis. Conventional testing on cancellation tasks with the right hand revealed reliable left neglect, but performance was significantly improved when the left hand was used. Investigations of (manual) line bisection showed normal performance with the right hand but right neglect when the left hand was used. Right neglect was also observed on a purely perceptual version of the line bisection task. We argue that the attentional vectors of the cerebral hemispheres can be modulated by (perceptual) task-demands and by (motorie) response demands. (JINS, 1996, 2, 412–418.)

scholarly journals Is it only humans that count from left to right?

2010 ◽  
Vol 6 (3) ◽  
pp. 290-292 ◽  
Author(s):  
Rosa Rugani ◽  
Debbie M. Kelly ◽  
Izabela Szelest ◽  
Lucia Regolin ◽  
Giorgio Vallortigara
Keyword(s):  
Gallus Gallus ◽  
Number Line ◽  
Ordinal Position ◽  
Nucifraga Columbiana ◽  
Correct Position ◽  
Leftward Bias ◽  
Starting Position ◽  
Domestic Chicks ◽  
The Right ◽  
Spatially Oriented

We report that adult nutcrackers ( Nucifraga columbiana ) and newborn domestic chicks ( Gallus gallus ) show a leftward bias when required to locate an object in a series of identical ones on the basis of its ordinal position. Birds were trained to peck at either the fourth or sixth element in a series of 16 identical and aligned positions. These were placed in front of the bird, sagittally with respect to its starting position. When, at test, the series was rotated by 90° lying frontoparallel to the bird's starting position, both species showed a bias for identifying selectively the correct position from the left but not from the right end. The similarity with the well-known phenomenon of the left-to-right spatially oriented number line in humans is considered.

scholarly journals Reconstructing the origins of the space-number association: spatial and number-magnitude codes must be used jointly to elicit spatially organised mental number lines

2018 ◽  
Author(s):  
Mario Pinto ◽  
Michele Pellegrino ◽  
Fabio Marson ◽  
Stefano Lasaponara ◽  
Fabrizio Doricchi
Keyword(s):  
Spatial Representation ◽  
Response Selection ◽  
Number Line ◽  
Mental Number Line ◽  
Number Magnitude ◽  
Number Lines ◽  
Series Of Experiments ◽  
Blue Arrow ◽  
Spatial Positioning ◽  
The Right

AbstractIn a series of recent studies we have pointed out that the use of contrasting left/right spatial codes, whether indirectly related to number magnitudes through response selection or directly associated to the same magnitudes to guide their spatial positioning on a mental number line, is crucial in eliciting space-number associations (Aiello, 2012; Fattorini et al., 2015; 2016; Pinto et al., 2018). Nonetheless, this conclusion is based on experiments in which spatial and number-magnitudes codes are used jointly during task performance. Here, in a series of unimanual Go/No-Go tasks with intermixed central numerical and pictorial targets, i.e. arrows pointing to the left or to the right, we explore whether spatial codes used in isolation inherently evoke the left-to-right representation of number magnitudes and, vice-versa, whether number-magnitude codes used in isolation inherently evoke the conceptual activation of left/right spatial codes. In a first series of experiments participants were asked to provide unimanual Go/N-Go responses based on instructions that activated only magnitude codes, e.g. “push only if the number is lower than 5 and whenever an arrow appears”, or only spatial codes, e.g. “push only when an arrow points to the left and whenever a number appears”. In a second series of experiments, the same numerical instructions were combined with the request of responding only to arrows in a specific colour, e.g. “push when the number is lower than 5 and whenever a blue arrow appears”. At variance with a recent experiment by Shaki and Fischer (2018), in our experiments no constant association was present between a specific arrow colour and a specific arrow direction. The results of these experiments highlight no space-number congruency effects: e.g. no faster RTs to arrows pointing to the left rather than to the right when participants attend to numbers lower than 5 and, vice-versa, no faster RTs to numbers lower than 5 rather than higher, when participants attend to arrows pointing to the left. Based on these findings it must be concluded that neither space codes used in isolation can elicit a spatial representation of number magnitudes nor number-magnitude codes used in isolation can trigger the activation of spatial codes. Thus, spatial and numerical codes must be used jointly to evoke spatially organised mental number lines.

The Development of the Mental Representation of Numbers 0-10 in Elementary School Children

2020 ◽  
Author(s):  
Anat Feldman ◽  
Michael Shmueli ◽  
Dror Dotan ◽  
Joseph Tzelgov ◽  
Andrea Berger
Keyword(s):  
Sixth Grade ◽  
Number Line ◽  
Number Representation ◽  
Large Numbers ◽  
Position Task ◽  
Sigmoidal Curve ◽  
Anchor Points ◽  
The Right ◽  
Line P ◽  
Best Fit

In recent years, there has been growing interest in the development of mental number line (MNL) representation examined using a number-to-position task. In the present study, we investigated the development of number representation on a 0-10 number line using a computerized version of the number-to-position task on a touchscreen, with restricted response time; 181 children from first through sixth grade were tested. We found that the pattern of estimated number position on the physical number line was best fit by the sigmoidal curve function–which was characterized by underestimation of small numbers and overestimation of large numbers–and that the breakpoint changed with age. Moreover, we found that significant developmental leaps in MNL representation occurred between the first and second grades and again between the second and third grades, which was reflected in the establishment of the right endpoint and the number 5 as anchor points, yielding a more accurate placement of other numbers along the number line.

EXPRESS: Spatial-numerical associations from a novel paradigm support the Mental Number Line account

2021 ◽  
pp. 174702182110087
Author(s):  
Lauren Aulet ◽  
Sami R Yousif ◽  
Stella Lourenco
Keyword(s):  
Memory Task ◽  
Verbal Working Memory ◽  
Number Line ◽  
Mental Number Line ◽  
Task Demands ◽  
Numerical Magnitude ◽  
The Novel ◽  
Alternative Account ◽  
Subject Design ◽  
Multiple Tasks

Multiple tasks have been used to demonstrate the relation between numbers and space. The classic interpretation of these directional spatial-numerical associations (d-SNAs) is that they are the product of a mental number line (MNL), in which numerical magnitude is intrinsically associated with spatial position. The alternative account is that d-SNAs reflect task demands, such as explicit numerical judgments and/or categorical responses. In the novel ‘Where was The Number?’ task, no explicit numerical judgments were made. Participants were simply required to reproduce the location of a numeral within a rectangular space. Using a between-subject design, we found that numbers, but not letters, biased participants’ responses along the horizontal dimension, such that larger numbers were placed more rightward than smaller numbers, even when participants completed a concurrent verbal working memory task. These findings are consistent with the MNL account, such that numbers specifically are inherently left-to-right oriented in Western participants.

Task-Irrelevant Sound Corrects Leftward Spatial Bias in Blindfolded Haptic Placement Task

2020 ◽  
Vol 33 (4-5) ◽  
pp. 521-548
Author(s):  
Laura Cacciamani ◽  
Larisa Sheparovich ◽  
Molly Gibbons ◽  
Brooke Crowley ◽  
Kalynn E. Carpenter ◽  
...  
Keyword(s):  
Memory Task ◽  
Spatial Location ◽  
Dominant Hand ◽  
Spatial Bias ◽  
Leftward Bias ◽  
Object Location Memory ◽  
Irrelevant Sound ◽  
Haptic Object ◽  
The Right ◽  
Task Irrelevant

Abstract We often rely on our sense of vision for understanding the spatial location of objects around us. If vision cannot be used, one must rely on other senses, such as hearing and touch, in order to build spatial representations. Previous work has found evidence of a leftward spatial bias in visual and tactile tasks. In this study, we sought evidence of this leftward bias in a non-visual haptic object location memory task and assessed the influence of a task-irrelevant sound. In Experiment 1, blindfolded right-handed sighted participants used their non-dominant hand to haptically locate an object on the table, then used their dominant hand to place the object back in its original location. During placement, participants either heard nothing (no-sound condition) or a task-irrelevant repeating tone to the left, right, or front of the room. The results showed that participants exhibited a leftward placement bias on no-sound trials. On sound trials, this leftward bias was corrected; placements were faster and more accurate (regardless of the direction of the sound). One explanation for the leftward bias could be that participants were overcompensating their reach with the right hand during placement. Experiment 2 tested this explanation by switching the hands used for exploration and placement, but found similar results as Experiment 1. A third Experiment found evidence supporting the explanation that sound corrects the leftward bias by heightening attention. Together, these findings show that sound, even if task-irrelevant and semantically unrelated, can correct one’s tendency to place objects too far to the left.

The role of visual experience for spatial numerical associations

2012 ◽  
Vol 25 (0) ◽  
pp. 222 ◽  
Author(s):  
Michael J. Proulx ◽  
Achille Pasqualotto ◽  
Shuichiro Taya
Keyword(s):  
Visual Experience ◽  
Opposite Effect ◽  
Random Number Generation ◽  
Number Line ◽  
Mental Number Line ◽  
Generation Task ◽  
Congenitally Blind ◽  
Left And Right ◽  
The Right

The topographic representation of space interacts with the mental representation of number. Evidence for such number–space relations have been reported in both synaesthetic and non-synaesthetic participants. Thus far most studies have only examined related effects in sighted participants. For example, the mental number line increases in magnitude from left to right in sighted individuals (Loetscher et al., 2008, Curr. Biol.). What is unclear is whether this association arises from innate mechanisms or requires visual experience early in life to develop in this way. Here we investigated the role of visual experience for the left to right spatial numerical association using a random number generation task in congenitally blind, late blind, and blindfolded sighted participants. Participants orally generated numbers randomly whilst turning their head to the left and right. Sighted participants generated smaller numbers when they turned their head to the left than to the right, consistent with past results. In contrast, congenitally blind participants generated smaller numbers when they turned their head to the right than to the left, exhibiting the opposite effect. The results of the late blind participants showed an intermediate profile between that of the sighted and congenitally blind participants. Visual experience early in life is therefore necessary for the development of the spatial numerical association of the mental number line.

scholarly journals A Meta-Analysis of Line Bisection and Landmark Task Performance in Older Adults

2021 ◽  
Author(s):  
Gemma Learmonth ◽  
Marietta Papadatou-Pastou
Keyword(s):  
Meta Analysis ◽  
Line Length ◽  
Line Bisection ◽  
Group Level ◽  
Bisection Task ◽  
Leftward Bias ◽  
State Dependent ◽  
The Right ◽  
Meta Analyses ◽  
Line Bisection Task

AbstractYoung adults exhibit a small asymmetry of visuospatial attention that favours the left side of space relative to the right (pseudoneglect). However, it remains unclear whether this leftward bias is maintained, eliminated or shifted rightward in older age. Here we present two meta-analyses that aimed to identify whether adults aged ≥50 years old display a group-level spatial attention bias, as indexed by the line bisection and the landmark tasks. A total of 69 datasets from 65 studies, involving 1654 participants, were analysed. In the meta-analysis of the line bisection task (n = 63), no bias was identified for studies where the mean age was ≥50, but there was a clear leftward bias in a subset where all individual participants were aged ≥50. There was no moderating effect of the participant’s age or sex, line length, line position, nor the presence of left or right cues. There was a small publication bias in favour of reporting rightward biases. Of note, biases were slightly more leftward in studies where participants had been recruited as part of a stand-alone older group, compared to studies where participants were recruited as controls for a clinical study. Similarly, no spatial bias was observed in the meta-analysis of the landmark task, although the number of studies included was small (n = 6). Overall, these results indicate that over 50s maintain a group-level leftward bias on the line bisection task, but more studies are needed to determine whether this bias can be modulated by stimulus- or state-dependent factors.

Postural adjustments for online corrections of arm movements in standing humans

2011 ◽  
Vol 105 (5) ◽  
pp. 2375-2388 ◽  
Author(s):  
Julia A. Leonard ◽  
Valeriya Gritsenko ◽  
Ryan Ouckama ◽  
Paul J. Stapley
Keyword(s):  
Muscle Activity ◽  
Arm Movements ◽  
Task Demands ◽  
Target Displacement ◽  
Postural Adjustments ◽  
Central Target ◽  
Postural Muscle ◽  
Online Corrections ◽  
Standing Humans ◽  
The Right

The aim of this study was to investigate how humans correct ongoing arm movements while standing. Specifically, we sought to understand whether the postural adjustments in the legs required for online corrections of arm movements are predictive or rely on feedback from the moving limb. To answer this question we measured online corrections in arm and leg muscles during pointing movements while standing. Nine healthy right-handed subjects reached with their dominant arm to a visual target in front of them and aligned with their midline. In some trials, the position of the target would switch from the central target to one of the other targets located 15°, 30°, or 45° to the right of the central (midline) target. For each target correction, we measured the time at which arm kinematics, ground reaction forces, and arm and leg muscle electromyogram significantly changed in response to the target displacement. Results show that postural adjustments in the left leg preceded kinematic corrections in the limb. The corrective postural muscle activity in the left leg consistently preceded the corrective reaching muscle activity in the right arm. Our results demonstrate that corrections of arm movements in response to target displacement during stance are preceded by postural adjustments in the leg contralateral to the direction of target shift. Furthermore, postural adjustments preceded both the hand trajectory correction and the arm-muscle activity responsible for it, which suggests that the central nervous system does not depend on feedback from the moving arm to modify body posture during voluntary movement. Instead, postural adjustments lead the online correction in the arm the same way they lead the initiation of voluntary arm movements. This suggests that forward models for voluntary movements executed during stance incorporate commands for posture that are produced on the basis of the required task demands.

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