Pitch memory: an advantage for the left-handed

Effects of Spatial Location of Auditory Tones on Pitch Discrimination

Pitch discrimination accuracy has been found to be affected by many factors, including handedness, musical training, interfering stimuli, and spatial location of the auditory stimulus. Separating the stimulus input location of interference tones from initial (reference) and final (comparison) tones leads to more accurate pitch discrimination, but the effects of spatial location relationships between the reference, interference, and comparison tones have not been fully explored. This study examined the impact of stimulus spatial location in 24 young, nonmusician females. Participants determined whether the pitch of reference and comparison tones were the same or different in 20 pitch discrimination conditions with varied interference, spatial relationships, and frequencies. Findings revealed that pitch discrimination accuracy was significantly better when (a) there was no interference, (b) the comparison tone was presented to the contralateral brain hemisphere from reference and interference tones, and (c) the comparison tone was presented to the left ear. We discussed the implications of these findings for therapy programs to strengthen pitch discrimination abilities.

The Role of Pitch Memory in Pitch Discrimination and Pitch Matching

Accurate control of vocal pitch (fundamental frequency) requires coordination of sensory and motor systems. Previous research has supported the relationship between perceptual accuracy and vocal pitch matching accuracy. The purpose of this study was to investigate the role of memory for pitch in pitch matching and pitch discrimination ability. Three experimental tasks were used. First, a pitch matching task was completed, in which the participants listened to target tones and vocally matched the pitch of the tones. The second task was a pitch discrimination task that required the participants to judge the pitch (same or different) of complex tone pairs. The third task was pitch discrimination with memory interference task that was similar to the pitch discrimination task except interference tones were added. Results of the pitch matching and pitch discrimination tasks yielded a significant correlation between these values. When there was memory interference, pitch discrimination ability was poorer, and there was no significant correlation between pitch discrimination and pitch matching. These results support earlier findings of a relationship between pitch discrimination and pitch matching abilities. The results also suggest a possible role of pitch memory in both tasks. These findings may have implications for abilities related to accurate pitch control.

Do left-handed children have advantages regarding school performance and leadership skills?

A handedness polymorphism exists in all human populations so far investigated, at least since the Palaeolithic. Handedness is a heritable trait, and a possible evolutionary explanation for the higher prevalence of right-handers is the association of left-handedness with some deleterious traits. In this context, the persistence of left-handers remains unexplained. Reproductive success has been shown to be dependent on cultural success in many human societies. This study is the first attempt to consider the importance of social status to evolutionary processes related to handedness. We conducted a survey in French public primary schools to look for a possible association between laterality, school performance, and leadership skills. This study revealed only weak associations, and a sex effect. For primary-school girls, we report a negative association between several indicators of left-sidedness and teacher's ratings of school performance and leadership skills. For primary-school boys, we report a positive association between left-handedness for writing and teacher's ratings of school performance. The present study did not reveal any strong relation between laterality and school performance, but has shown that general school performance is not independent of laterality, and that the effect is opposite in males and females. The main difficulty is now to define clearly the different intellectual functions involved.

The subjective size of melodic intervals over a two-octave range

Musically trained and untrained participants provided magnitude estimates of the size of melodic intervals. Each interval was formed by a sequence of two pitches that differed by between 50 cents (one half of a semitone) and 2,400 cents (two octaves) and was presented in a high or a low pitch register and in an ascending or a descending direction. Estimates were larger for intervals in the high pitch register than for those in the low pitch register and for descending intervals than for ascending intervals. Ascending intervals were perceived as larger than descending intervals when presented in a high pitch register, but descending intervals were perceived as larger than ascending intervals when presented in a low pitch register. For intervals up to an octave in size, differentiation of intervals was greater for trained listeners than for untrained listeners. We discuss the implications for psychophysical pitch scales and models of music perception.

Handedness differences in widths of right and left craniofacial regions in healthy young adults

In this work, handedness differences in the widths of right and left craniofacial regions were studied in a healthy sample of 39 male and 43 female students, 17 to 23 years old. Width of craniofacial regions was assessed by computerized tomography. Handedness was associated with the left face width especially for women. The left facial region was larger for right-handers than left-handers. The smaller measure for the left face of left-handers might be associated with an advantage of left ear sensitivity.

Dyslexia and music: measuring musical timing skills

Over the last few decades, a growing amount of research has suggested that dyslexics have particular difficulties with skills involving accurate or rapid timing, including musical timing skills. It has been hypothesised that music training may be able to remediate such timing difficulties, and have a positive effect on fundamental perceptual skills that are important in the development of language and literacy skills (Overy, 2000). In order to explore this hypothesis further, the nature and extent of dyslexics' musical difficulties need to be examined in more detail. In the present study, a collection of musical aptitude tests (MATs) were designed specifically for dyslexic children, in order to distinguish between a variety of musical skills and sub-skills. 15 dyslexic children (age 7-11, mean age 9.0) and 11 control children (age 7-10, mean age 8.9) were tested on the MATs, and their scores were compared. Results showed that the dyslexic group scored higher than the control group on 3 tests of pitch skills (possibly attributable to slightly greater musical experience), but lower than the control group on 7 out of 9 tests of timing skills. Particular difficulties were noted on one of the tests involving rapid temporal processing, in which a subgroup of 5 of the dyslexic children (33%) (mean age 8.4) was found to account for all the significant error. Also, an interesting correlation was found between spelling ability and the skill of tapping out the rhythm of a song, which both involve the skill of syllable segmentation. These results support suggestions that timing is a difficulty area for dyslexic children, and suggest that rhythm skills and rapid skills may need particular attention in any form of musical training with dyslexics.

Superior episodic memory is associated with interhemispheric processing

The dependence of episodic memories on interhemispheric processing was tested. In Experiment 1, positive familial sinistrality (FS+; e.g., presence of left-handed relatives) was associated with superior episodic memory and inferior implicit memory in comparison with negative familial sinistrality (i.e., FS-). This reflected a greater degree of interhemispheric interaction in FS+ participants, which was hypothesized as facilitating episodic memory. In Experiment 2, the authors directly manipulated inter- versus intrahemispheric processing using tests of episodic (recognition) and semantic (lexical decision) memory in which letter strings were presented twice within trial blocks. Semantic memory was superior when the 2nd presentation went to the same hemisphere as the 1st. Episodic memory, however, was superior when the 2nd presentation of a stimulus went to the opposite hemisphere. Results support an interhemispheric processing basis for episodic memories.

Pitch perception: a difference between right- and left-handed listeners

Various results indicate that the perception of a complex tone's "virtual" pitch is generally lateralized in the right cerebral hemisphere. The primary aim of this work was to test the hypothesis that this is not the case for the "spectral" pitch percepts induced by complex tones. Forty right-handed and 18 left-handed listeners were monaurally presented with pairs of successive tones made up of n consecutive equal-amplitude harmonics of a missing fundamental (F0). n varied from two to four across subjects. In "test" conditions, the paired tones differed in F0 but the spectral components of the tone with the lower F0 were higher in frequency than the corresponding components of the other tone (except for one component, which was identical). The subjects had to say if, from one tone to the other, pitch rose or fell. From such judgements, one could infer that the pitch dominantly perceived in each tone was a virtual pitch (corresponding to F0) or a spectral pitch (i.e., the pitch of a single spectral component, or a perceptual quality corresponding to the centroid of the power spectrum). For n = 2, the results indicated that virtual pitch was less salient than spectral pitch; the opposite occurred for n = 3 and n = 4. The ear (left or right) to which the stimuli were presented had some influence on the judgements, in the expected direction. However, this influence was not a robust one. Unexpectedly, a reliable effect of the listeners' handedness was observed: for each value of n, the judgements indicating virtual pitch perception were less frequent in the left-handers than in the right-handers. Discrimination performances measured in "control" conditions showed that the handedness factor was not confounded with a factor of frequency discrimination ability.

Handedness and spatial ability

Data from a large-scale study of cognitive abilities were used to test the hypothesis that there are handedness-related differences in spatial visualization. The spatial factor score of the cognitive test battery provided a measure of spatial visualization. Analyses revealed a sex X handedness X ethnicity interaction on the spatial factor, and no significant handedness-related differences on verbal factor. In all ethnic groups strongly left-handed males had higher spatial scores than strongly right-handed males, whereas strongly left-handed females had lower spatial scores than strongly right-handed females. Among subjects of Japanese or Chinese ancestry, strongly left-handed subjects differed from ambidextrous subjects as well as from right-handed subjects, and these differences, too, were of opposite sign for males and females. It is suggested that the use of spatial ability measures which are relatively insensitive to differences in right hemisphere ability, as well as the failure to attend to degree of handedness, ethnicity, and particularly gender, may be responsible for the negative findings in this area of research.

A dichotic rhythm task: advantage for the left-handed

Right- and left-handed subjects responded to a task which required identification of signal events embedded in four-beat dichotic rhythm patterns. Left-handed subjects reported a significantly greater number of signals from both ears than did right-handed subjects. The results suggested that left-handed subjects may be better able to analyze simultaneous stimuli and integrate differential information from them into a coherent response structure. The data further support a bi-dominant theory of left-handedness.