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No description available.

The purpose of this project is to develop a website that helps left handed students, their parents, and teachers to help left-handers, whether they are left-or-right-brain dominant, succeed. This website will be a tool to get to know their children and students better. The project consists of a paper and a website to educate about left-handed people.

The database on hand preferences in non-human primates provides inconsistent and inconclusive findings, and is plagued by gaps and methodological issues. I studied hand preferences in the bonobo, which is a very interesting model for investigating evolutionary hypotheses on human handedness. There are few previous data on bonobos and they are from small samples and for relatively simple tasks. I studied a large sample of 94 bonobos in three zoos and one sanctuary, on a variety of actions. Five studies were performed to record: 1. hand use for spontaneous daily actions (non-social). 2. hand use for the tube task , a task that requires a manipulative bimanual coordinated precise action. 3. hand use for using a stick as a probe ( termite fishing ). 4. hand use for spontaneous social actions and gestures, recorded during their social interactions (intra-specific) and during interactions with humans (inter-specific). 5. hand use for induced begging gestures (begging for food from the observer). The results show significant manual laterality in almost all the behaviours studied. The hand preferences were present on an individual basis. The numbers of right-handed and left-handed individuals were similar, indicating no group-level bias, for any of the actions studied. There was no significant effect of the settings, rearing history, sex and age (except in study 2 where adults were more right-handed than younger subjects). I examined different factors that have been proposed as selective pressures for the emergence of handedness. Laterality was influenced by: postural demands (posture, activity of the other hand), precision, grip type, manipulation or bimanual coordination, tool-use, throwing, communication. Notably, the laterality was very marked for the tube task , the termite fishing task and the begging experiment, which suggests that the factors involved in these tasks could be important factors regarding laterality.

Most humans do not only have a preferred hand to use in different situations, they also exhibit a clear preference when it comes to eye usage. Few studies have assessed whether different tests of eye preference give congruent or incongruent results, and furthermore, there are conflicting findings on whether eye preference correlates with eye dominance, visual acuity, and handedness. The present study assessed whether these variables correlate, alongside factors such as age and sex. A total of 79 subjects, 45 males and 34 females, were tested. A microscope, telescope, photo camera, and caleidoscope were used to assess eye preference, the Dolman test was used to assess eye dominance, the Edinburgh Handedness Inventory was filled in to assess handedness, and visual acuity was measured using a Snellen chart. Care was taken to include subjects of various ages and both sexes. Descriptive statistics show that most subjects were right-handed, had a right-eye preference and were consistent across the four eye preference tasks, and had a dominant right eye. Significant correlations were found between visual acuity and handedness, as well as eye preference and eye dominance.

Thesis (Ed.M.)--Boston University / The intention of this study is to examine the quality and quantitative achievements of two hundred seventy-nine left handed children located in the elementary schools of New England.

Two studies investigated the effects of various motor constraints of reaching on infants’ search performance on the A-not-B task. These studies were motivated by the idea that motor memories for reaching lead to A-not-B errors. The 2 motor constraints that were evaluated included barriers that blocked the path of the hand and hand-use preferences. Each of these motor constraints was examined separately. In Experiment 1, infants (N = 40, 20 8-month olds, 20 16-month olds) were given the A-not-B task twice. One condition was analogous to the traditional A-not-B task (i.e., using 2 hiding locations) and the other was modified such that a barrier (i.e., an opaque screen) blocked the infants’ reaching path of location A on A trials only. On A trials, all infants searched correctly less often when a barrier was present, and younger infants searched correctly less often than older infants. On B trials, younger infants made more errors in the no barrier condition, whereas older infants did not show any significant difference in B trial performance across conditions. In Experiment 2, infants (N = 51) completed an adapted handedness test (Michel, Ovrut, & Harkins, 1985) followed by a modified A-not-B task. The test assessed infants’ hand-use preferences for reaching, which was used to group infants into their respective preference group (i.e., consistent or inconsistent). Infants with a consistent preference were randomly assigned to a hiding side group (i.e., A on preferred side or A on non-preferred side). Infants searched correctly more often when hiding side was congruent with their preferred reaching hand, and older infants searched correctly more often than younger infants. On the B trial, neither age nor hiding side affected the production of the A-not-B error. Collectively, these studies present data that address the theory that motor memories for reaching are the cause for the production of A-not-B error. These studies provide novel evidence that motor memories for reaching are present in infants aged 8- and 16-months, and that motor memories can influence the production of such errors in certain A-not-B contexts. Implications and directions for future research are also discussed.

Two studies investigated the effects of various motor constraints of reaching on infants’ search performance on the A-not-B task. These studies were motivated by the idea that motor memories for reaching lead to A-not-B errors. The 2 motor constraints that were evaluated included barriers that blocked the path of the hand and hand-use preferences. Each of these motor constraints was examined separately. In Experiment 1, infants (N = 40, 20 8-month olds, 20 16-month olds) were given the A-not-B task twice. One condition was analogous to the traditional A-not-B task (i.e., using 2 hiding locations) and the other was modified such that a barrier (i.e., an opaque screen) blocked the infants’ reaching path of location A on A trials only. On A trials, all infants searched correctly less often when a barrier was present, and younger infants searched correctly less often than older infants. On B trials, younger infants made more errors in the no barrier condition, whereas older infants did not show any significant difference in B trial performance across conditions. In Experiment 2, infants (N = 51) completed an adapted handedness test (Michel, Ovrut, & Harkins, 1985) followed by a modified A-not-B task. The test assessed infants’ hand-use preferences for reaching, which was used to group infants into their respective preference group (i.e., consistent or inconsistent). Infants with a consistent preference were randomly assigned to a hiding side group (i.e., A on preferred side or A on non-preferred side). Infants searched correctly more often when hiding side was congruent with their preferred reaching hand, and older infants searched correctly more often than younger infants. On the B trial, neither age nor hiding side affected the production of the A-not-B error. Collectively, these studies present data that address the theory that motor memories for reaching are the cause for the production of A-not-B error. These studies provide novel evidence that motor memories for reaching are present in infants aged 8- and 16-months, and that motor memories can influence the production of such errors in certain A-not-B contexts. Implications and directions for future research are also discussed.

The origin and development of human cerebral asymmetries is yet a debated issue. One prominent manifestation of cerebral asymmetry is handedness with humans showing a dextral population bias. Handedness in humans is not fully established before the age of six. However, head turning preference in newborns is thought to be an important factor in the development of later handedness. If this head turning preference did not disappear completely during development but would prevail into adulthood it might, thus, be associated with handedness. Therefore, this study aimed to assess head turning preference in adults and to relate a possibly emerging bias to handedness. Forty-two adults (6 females, aged 23- 63, mean age = 35) participated in the study. Head turning preference was assessed by means of a move during Ju Jutsu martial arts training, which requires the trainee to move the head to either left or right. The direction of head movement is not specified for this move, leaving the choice to the trainee. Handedness was measured by the Edinburgh Handedness Inventory. Results did not reveal a profound head turning bias in adults. Contrary to the dextral bias in handedness, in this study a leftward bias in head turning emerged from those participants who showed a head turning preference. Head turning bias did not depend on handedness. The finding of a nearly absent and predominantly leftward head turning bias in this sample is discussed in the context of the Ju Jutsu task, training experience and trainer bias. It is concluded that the Ju Jutsu move is not a sufficient task to assess head turning preference in humans. Thus, to further illuminate the relation between head turning preference and handedness, studies are needed which assess head turning preference in adults in an un-trainable and unbiased situation.

Denna studie syftar till fördjupade kunskaper om hur gitarrlärare ser på vänsterhänthet i relation till instrumentets speltekniska svårigheter och hur de anser sig arbeta med vänsterhänta elever i sin undervisning. I uppsatsen ges en bakgrund om vad vänsterhänthet är, en historisk bakgrund om den klassiska gitarren och dess speltekniska svårigheter samt tidigare forskning om musikundervisning av vänsterhänta. Studien utgår från ett multimodalt designteoretiskt perspektiv och ett empiriskt material bestående av fyra kvalitativa intervjuer. Av studiens resultat framkommer att de deltagande lärarna inte ansåg sig anpassa sin undervisning efter elevernas vänsterhänthet, förutom vid starkare grader av vänsterhänthet då eleverna uppmanades att vända på gitarren. Valet av hur gitarren ska hållas beskrivs sällan överlåtas till den enskilda eleven, utan förefaller istället vanligen bestämmas av läraren. Lärarna menade också att alla elever behöver öva samma tekniker och att samma undervisning därför bör gälla för höger- såväl som vänsterhänta elever. Den högersträngade gitarren utgör norm i undervisningen, vilket lärarnas berättelser om hur de sällan rekommenderade elever att vända på gitarren visar. Utifrån detta resultat diskuteras sedan gitarrundervisning av vänsterhänta. Undervisningen beskrivs inte enbart vara en fråga om att anpassa ett instrument, då hela undervisningens design beskrivs spela roll för elevernas lärande med instrumentet. / The purpose of this study is to gain a deeper knowledge of how guitar teachers view left-handedness with regard to the technical difficulties of the instrument and how they work with left-handed students while teaching. This paper provides some background on what left-handedness is, some historical background on the classical guitar and the technical difficulties of playing it, and an overview of previous work on musical education and left-handed people. The study is based on a multimodal and design theoretical perspective, and an empirical material consisting of four qualitative interviews. The results show that the participating teachers did not, in their own view, adapt their teaching because of left-handed students. The exception was students with a strong degree of left-handedness, who were encouraged to turn the guitar around. However, how the guitar is held was not often described as something left up to the individual student, but rather as something decided by the teacher. The teachers also felt that all students need to practice the same techniques, and that the same instructions therefore should be used for both right-handed and left-handed students. Right-handed guitars are standard in teaching situations, and the fact that the teachers say that they rarely recommend that students turn the guitar around reflects that. The results of the study then form the basis for a discussion on teaching left-handed students. It is not just a question of adapting an instrument; the whole design of the lessons makes a difference when it comes to the student learning the instrument.