scholarly journals Clinical psychomotor skills among left and right handed medical students: are the left-handed medical students left out?

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Sami Alnassar ◽  
Aljoharah Nasser Alrashoudi ◽  
Mody Alaqeel ◽  
Hala Alotaibi ◽  
Alanoud Alkahel ◽  
...  
Keyword(s):  
Medical Students ◽  
Psychomotor Skills ◽  
Left Handed ◽  
Left And Right

Lifted-Weight Difference Thresholds as a Function of Hand

1978 ◽  
Vol 46 (1) ◽  
pp. 175-178 ◽  
Author(s):  
William A. Siders ◽  
Harry Hoffman ◽  
Bradley B. Glanville
Keyword(s):  
College Students ◽  
Weight Changes ◽  
Weight Difference ◽  
Left Handed ◽  
Perceived Weight ◽  
Left And Right ◽  
Difference Thresholds

A study was conducted to determine if the two hands of right-handers are differentially sensitive to changes in perceived weight. Using the method of limits, the left and right hands of 20 college students were tested at each of three reference weights: 90, 100, and 110 gm. Results indicated that, over-all, difference thresholds for the two hands were not reliably different, though a trend did emerge toward greater right-handed sensitivity to weight changes at smaller weights and greater left-handed sensitivity at greater weights.

Handedness affects Emotional Valence Asymmetry

1989 ◽  
Vol 68 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Richard A. McFarland ◽  
Robert Kennison
Keyword(s):  
Negative Affect ◽  
Hemispheric Asymmetry ◽  
Emotional Responses ◽  
Emotional Valence ◽  
Left Handed ◽  
Two Factors ◽  
Left And Right ◽  
The Asymmetry ◽  
The Right ◽  
Cerebral Processing

Music was played monaurally to 80 right-handed and 80 left-handed subjects. Right-handers reported more positive and less negative affect if the music was to the right ear. Left-handers reported experiencing more positive and less negative affect during music to the left ear. The hand × ear interaction was significant. The valence of emotional responses to the music seems influenced by a combination of at least two factors, (1) differences between left- and right-handers in the cerebral processing of emotional valence and (2) differences in the processing of emotional valence within each handedness group depending upon which hemisphere was initially most strongly engaged by the music. These results partially corroborate and extend the findings of previous studies in which briefer stimuli were presented tachistoscopically or dichotically. It is concluded that, while there is hemispheric asymmetry in the processing of emotional valence, the direction of the asymmetry may be associated with the handedness of the subjects.

scholarly journals Individual Laterality in Ghost Crabs (Ocypode saratan) Influences Burrowing Behavior

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1512
Author(s):  
Reuven Yosef ◽  
Michal Daraby ◽  
Alexei Semionovikh ◽  
Jakub Z. Kosicki
Keyword(s):  
Natural Selection ◽  
Red Sea ◽  
Selection Pressure ◽  
Left Handed ◽  
Self Defense ◽  
Temporal Segregation ◽  
Ghost Crabs ◽  
Left And Right ◽  
Burrowing Behavior ◽  
The Right

Behavioral handedness is known to enhance an individual’s handling capabilities. However, the ecological advantages in brachyuran crustaceans remain unclear, despite the Ocypode species having been studied extensively. Thus, in this study, we analyzed the laterality of the endemic Red Sea ghost crab on one beach in Eilat, Israel. We successfully documented the laterality of the large cheliped in 125 crabs; in 60 (48.0%), the right cheliped was larger, and in 64 (51.2%), the left. We also observed temporal segregation between the right- and left-clawed crabs. The right-handed crabs start activity just after sunrise, while left-handed crabs appear ca. 40 min after it. Similarly, temporal segregations were also observed in the evening. The right-clawed crab activity peaked ca. 20 min before sunset, while the left-clawed crabs were active uniformly. Additionally, burrow entrances corresponded to the larger cheliped of the resident individual and is probably a self-defense-related behavior. We conclude that cheliped laterality in O. saratan populations should be considered as a bimodal trait, where left- and right-handedness is not under natural selection pressure.

The Effect of the Operator's Handedness on Some Directional Stereotypes in Control-Display Relationships

1968 ◽  
Vol 10 (4) ◽  
pp. 303-320 ◽  
Author(s):  
Alphonse Chapanis ◽  
Bernard A. Gropper
Keyword(s):  
Initial Direction ◽  
Clockwise Rotation ◽  
Control Knob ◽  
Left Handed ◽  
Common Control ◽  
Direction Of Movement ◽  
The Subject ◽  
Left And Right ◽  
Vertical Scales

Recommendations about preferred directions of movement for controls and displays are based almost exclusively on right-handed persons. This experiment has studied some common control-display movement stereotypes to find out if these stereotypes are equally valid for left- and right-handed subjects. Our apparatus presented a scale that could be oriented horizontally or vertically. The numbers on the scale increased either right-to-left or left-to-right for the horizontal scales, or up-to-down or down-to-up for the vertical scales. The linkage between the movement of a control knob and the movement of the hairline on the scale was reversible so that a clockwise rotation of the knob could be made to move the hairline toward either end of the scale. We recorded (1) the direction of the first movement made by the subject on each trial, (2) the total number of reversal movements made on each setting, (3) the time taken to make a setting, and (4) the actual setting made (and so, of course, setting errors). We tested 64 subjects, 32 left-handed and 32 right-handed, each using his preferred and non-preferred hands. Significant differences were found in the time to make settings, the number of reversal movements, and errors in initial direction of movement as functions of handedness and the various apparatus relationships. In addition to overall differences between the performance of the left- and right-handed subjects, the two groups behaved differently on some measures when using their preferred and non-preferred hands.

scholarly journals ON FERMION ZERO MODES IN INSTANTON V - A MODELS WITH SPONTANEOUS SYMMETRY BREAKING

1994 ◽  
Vol 09 (08) ◽  
pp. 715-723
Author(s):  
KAMRAN SARIRIAN
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Electroweak Theory ◽  
Yukawa Couplings ◽  
Zero Modes ◽  
Left Handed ◽  
Fermion Masses ◽  
Left And Right

The left- and right-handed fermion zero modes are examined. Their behavior under the variation of the size of the instanton, ρ I , and the size of the Higgs core, ρ H , for a range of Yukawa couplings corresponding to the fermion masses in the electroweak theory are studied. It is shown that the characteristic radii of the zero modes, in particular those of the left-handed fermions, are locked to the instanton size, and are not affected by the variation of ρ H , except for fermion masses much larger than those in the standard electroweak theory.

Do turning biases by the 7-spot ladybird, Coccinella septempunctata, increase their foraging efficiency?

Behaviour ◽  
2007 ◽  
Vol 144 (2) ◽  
pp. 143-163 ◽  
Author(s):  
Mark Hassall ◽  
John Turner ◽  
Robbie Girling
Keyword(s):  
Coccinella Septempunctata ◽  
Plant Size ◽  
Foraging Strategy ◽  
Foraging Efficiency ◽  
Left Handed ◽  
Y Maze ◽  
Aphid Density ◽  
Left And Right ◽  
Number Of Individuals ◽  
Mean Time

AbstractThe hypothesis that foraging male and female Coccinella septempunctata L. would exhibit a turning bias when walking along a branched linear wire in a Y-maze was tested. Individuals were placed repeatedly in the maze. Approximately 45% of all individuals tested displayed significant turning biases, with a similar number of individuals biased to the left and right. In the maze right-handed individuals turned right at 84.4% of turns and the left-handed individuals turned left at 80.2% of turns. A model of the searching efficiency of C. septempunctata in dichotomous branched environments showed that model coccinellids with greater turning biases discovered a higher proportion of the plant for a given number of searches than those with no bias. A modification of the model to investigate foraging efficiency, by calculating the mean time taken by individuals to find randomly distributed aphid patches, suggested that on four different sizes of plants, with a variety of aphid patch densities, implementing a turning bias was a significantly more efficient foraging strategy than no bias. In general the benefits to foraging of implementing a turning bias increased with the degree of the bias. It may be beneficial for individuals in highly complex branched environments to have a turning bias slightly lower than 100% in order to benefit from increased foraging efficiency without walking in circles. Foraging bias benefits increased with increasing plant size and decreasing aphid density. In comparisons of two different plant morphologies, one with a straight stem and side branches and one with a symmetrically branched morphology, there were few significant differences in the effects of turning biases on foraging efficiency between morphologies.

Asymmetries in Ear Movements and Eyebrow Raising in Men and Women and Right- and Left-Handers

1995 ◽  
Vol 80 (3_suppl) ◽  
pp. 1147-1154 ◽  
Author(s):  
Chris Code
Keyword(s):  
Sex Differences ◽  
Right Hemisphere ◽  
The Other ◽  
Modern Humans ◽  
Environmental Sounds ◽  
Men And Women ◽  
Left Handed ◽  
Left And Right ◽  
By Products

The abilities to move ears and eyebrows were examined in 442 subjects (204 men, 238 women) categorized as right-handed ( n = 382) and left-handed ( n = 60, including mixed and ambidextrous-handed subjects). Approximately 22% could move one or the other ear and about 18% could move both ears simultaneously, but significantly more men could move both ears simultaneously. Significantly more men than women were able to move both the left and right eyebrow and the left ear. No differences were observed between right- and left-handers. Significant contingency correlations were observed between raising eyebrows and moving ears. Results are discussed with reference to a possible left ear-right hemisphere advantage for localising environmental sounds, primitive ear-moving abilities no longer functional in modern humans, and epiphenomenal by-products of other adaptive sex differences.

Note on a Failure to Find Hemispheric Asymmetries for a Small Sample of Strongly Left- and Right-Handed Males and Females Using Verbal and Visuo-Spatial Recall

1980 ◽  
Vol 51 (1) ◽  
pp. 139-145 ◽  
Author(s):  
David K. Charman
Keyword(s):  
Visual Field ◽  
Small Sample ◽  
Hemispheric Asymmetries ◽  
Left Handed ◽  
Negative Findings ◽  
Left And Right ◽  
Males And Females ◽  
Spatial Positioning ◽  
Female Subjects

A column of letters was presented to the left, right, or center of the visual field of 10 male and 10 female subjects. 5 of each sex were either strongly left- or right-handed. The subjects' task was to position correctly the letters on a recall sheet. No significant hemispheric asymmetries emerged, a result that reflects other negative findings. The 10 females were significantly better at verbal identification; this was congruent with the literature. The 10 males and 10 females were equal in visuo-spatial (positioning) judgments; this did not support the literature. The 5 right-handed males were significantly inferior to the 5 left-handed males and the 10 females at positioning judgments, a result that remained unexplained. The findings were discussed in terms of other contradictory findings.

scholarly journals Handedness and gender influence blood pressure in young healthy men and women: A pilot study

2016 ◽  
Vol 50 (1) ◽  
pp. 10-15 ◽  
Author(s):  
I Rueda ◽  
I Banegas ◽  
I Prieto ◽  
R Wangensteen ◽  
AB Segarra ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sex Hormones ◽  
Sex Steroids ◽  
Menstrual Phase ◽  
Men And Women ◽  
Left Handed ◽  
Gender Influence ◽  
Left And Right ◽  
And Gender ◽  
The Right

AbstractObjective. The type and level of sex steroids influence blood pressure (BP). It has been suggested that functional brain asymmetries may be influenced by sex hormones. In addition, there are inter-arm differences in BP not yet related with handedness. In this study, we hypothesize a possible association between sex hormones, handedness, and inter-arm differences in blood pressure.Methods. To analyze this hypothesis, we measured BP in the left and right arm of the left and right handed adult young men and women in menstrual and ovulatory phase and calculated their mean arterial pressure (MAP).Results. Significant differences depending on sex, arm, handedness or phase of the cycle were observed. MAP was mostly higher in men than in women. Remarkably, in women, the highest levels were observed in the left handed in menstrual phase. Interestingly, the level of handedness correlated negatively with MAP measured in the left arm of right-handed women in the ovulatory phase but positively with the MAP measured in the right arm of right-handed women in the menstrual phase.Conclusions. These results may reflect an asymmetrical modulatory influence of sex hormones in BP control.

scholarly journals Left-handedness is associated with greater fighting success in humans

2019 ◽  
Author(s):  
Thomas Richardson ◽  
R. Tucker Gilman
Keyword(s):  
Objective Measure ◽  
Selective Advantage ◽  
Human Populations ◽  
Sexually Dimorphic ◽  
Low Frequencies ◽  
Fighting Ability ◽  
Left Handedness ◽  
Left Handed ◽  
Left And Right ◽  
Female Fighters

AbstractLeft-handedness is a costly, sexually dimorphic trait found at low frequencies in all human populations. How the handedness polymorphism is maintained is unclear. The fighting hypothesis argues that left-handed men have a negative frequency-dependent advantage in violent intrasexual competition giving them a selective advantage. In support of this, many studies have found that left-handed men are overrepresented among modern professional fighters, but studies typically find no difference in fighting success between left and right-handed fighters. We studied over 13,800 professional boxers and mixed martial artists of varying abilities in three of the largest samples to test this hypothesis to date, finding robust evidence that left-handed fighters have greater fighting success. This held for both male and female fighters, and for both percentage of fights won and an objective measure of fighting ability. We replicated previous results showing that left-handed fighters are strongly overrepresented in professional combat sports, but left-handed fighters did not show greater variance in fighting ability, a hypothesis suggested in previous studies. Overall we find strong evidence consistent with the fighting hypothesis.

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