Library of Excerpts

Visuospatial Patterns and Heterochronic Theory

"In these non-industrialized populations, visuo-spatial ability as measured by Performance IQ scores predominates over verbal ability (Verbal IQ scores), and there is no sex difference (Berry 1966, 1976). More particularly, Kaerine (1981) studying an Australian aboriginal population with a semi-nomadic hunter and gathering life-style found that the aboriginal children performed at a significantly higher level than the Australian white children from high school she used as controls, when their spatial competence was compared. They used a visual (non-verbal) strategy, and their unusual spatial competence was combined with self-reliance and there was no obvious sex-difference. In contrast, there is a sexual dimorphism in cognitive ability in Western industrialized countries today. Females are reported to excel at tests of fluency, articulation, coding and perceptual speed (Verbal IQ scores) and males at tests of spatial visualization (Performance IQ scores). Male visuo-spatial ability is consistent, whereas the female verbal superiority varies. It seems therefore as if the decline in mean pubertal age by some 4 years (raised maturational rate) has reduced visuo-spatial ability, and may ask: what evidence do we have that there is a relation between rate of maturation and cognitive profile? There is an inverse relation between rate of maturation and spatial ability, whereas verbal ability is unaffected by maturational rate (Waber 1976, 1977). Late-maturing girls and boys (pubertal age 14 1/2 years & 16 1/2 years, respectively = mean + 1 SD according to Marchall & Tanner 1969,1970) invariably scored higher on spatial than on verbal tasks, regardless of sex. They also performed better than early-maturers 12 1/2 years & 14 1/2 years respectively = mean -1 SD) on tests of spatial ability, also regardless of sex. Maturational rate had no particular influence on verbal scores.' (Saugstad, L.F. (1989) Mental illness and cognition in relation to age at puberty: a hypothesis. Clinical Genetics 36 (3): pp. 163) [note: how closely connected is visuo-spatial abilities to the final stage of cognitive development, abstract thinking?]

“We traced spatial, verbal and musical abilities through a seven-year period of adolescence. When we started our study, 60 boys had reached a mean age of 11.72, 60 girls were 11.52 on average. Menarche and mutation served as markers for maturation. We found that early, mid, and late maturers differed on spatial orientation and on tactile-visual discrimination as measured with the Witelson task. No differences between the maturational groups emerged on verbal fluency and on Wing's Standardized Tests of Musical Intelligence. At some stages, sex differences on spatial, verbal, and musical tests emerged, and disappeared at others. The sex differences in performance levels were not associated with a sex-specific relationship between maturation rate and performance levels. We found indications of the usefulness of sex hormone measurement in relation to cognitive and musical development in adolescence.” (Hassler M (1991) Maturation rate and spatial, verbal, and musical abilities: a seven-year-longitudinal study. Int J Neurosci 58 (3-4): 183)

“Musical composers, instrumentalists, and painters were compared with nonmusicians from a student and from an nonstudent population on testosterone levels in saliva. This steroid served as a marker for physiological androgyny. The ANOVA showed a significant group by sex interaction. Male composers attained significantly lower mean testosterone values than male instrumentalists and male nonmusicians; female composers had significantly higher mean testosterone values than female instrumentalists and female nonmusicians. Painters of both sexes did not differ significantly from controls. Spatial ability was assessed in the five groups. Significant differences on spatial test performance were not reflected in differences on salivary testosterone. Our results showed that musical composers of both sexes were physiologically highly androgynous. Creative musical behavior was associated with testosterone levels that minimized sex differences.” (Hassler M (1991)Testosterone and artistic talents. Int J Neurosci 56 (1-4): 25)

“The relationship between the strength of left-handedness and spatial reasoning ability was studied in left-handed male and female subjects with and without familial sinistrality (FS). The degree of left-handedness was assessed by the Edinburgh Handedness Inventory. The spatial reasoning ability was measured by Cattell's Culture Fair Intelligence Test. It was found that there was a negative linear correlation between nonverbal IQ and the strength of left-handedness in females with and without FS, a quadratic relationship in male left-handers without FS and a positive linear correlation in male left-handers with FS. These results indicate that the brain may exhibit different patterns of cerebral organization in left-handers to sex and FS. It was concluded that the "crowding" hypothesis may apply only to a subgroup of left-handers, i.e., females with a greater bilaterality of cognitive functions than males.” (Tan U (1991) The relationships between nonverbal intelligence and the strength of left-hand preference in left-handers to sex and familial sinistrality. Int J Neurosci 58 (3-4):151)

“To determine the effect of androgen insensitivity on cognitive abilities, subjects with the syndrome of complete androgen insensitivity (AI) were compared to control males and females from the same kindred on the Spanish version of the Wechsler Adult Intelligence Scale (WAIS). All subjects had similar sociocultural backgrounds and only right-handed subjects were used in the primary analysis. This design was chosen to diminish the effect of critical variables on test performance, thereby highlighting the effect of androgen unresponsiveness on cognition. The results indicated that control males and females were superior to androgen insensitive subjects on the Perceptual Organization factor, which included five visuospatial subtests. Separate analysis of these subtests revealed that males performed significantly better than females on Block Design, Picture Completion, and Object Assembly, and better than androgen insensitive subjects on all five subtests. Females were superior to androgen insensitive subjects on four subtests (Block Design, Picture Completion, Digit Symbol, and Picture Arrangement). Despite the small sample size, when female siblings were compared to their AI sisters, they were also superior on these four visuospatial subtests. The difference between the Verbal Comprehension and Perceptual Organization factors was greatest in androgen-insensitive subjects, while control males demonstrated the least difference. Females and AI subjects did not differ from one another on the Freedom from Distractibility factor nor on the subtests comprising it, but their performances were poorer than control males. None of the groups differed significantly on Full Scale IQ, Verbal IQ, the Verbal Comprehension factor, or any subtests included in this category.” (Imperato-McGinley J, Pichardo M, Gautier T, Voyer D, Bryden MP(1991) Cognitive abilities in androgen-insensitive subjects: comparison with control males and females from the same kindred. Clin Endocrinol (Oxf) 34(5): 341)


"Regardless of sex, early maturing adolescents performed better on tests of verbal than spactial abilities, the late maturing one showed the opposite pattern. Those maturing late were more lateralized for speech than those maturing early. Sex differences in mental abilities, it is argued, reflect differences in the oranization of cortical function that are related to differential rates of physical maturation." (Waber, D.P. (1976) Sex differences in cognition: A function of maturation rates. Science 192: pp. 572)

"The striking relation between rate of physical maturation (independent of sex) and spatial ability, verbal-spatial patterns and lateralization has several important implications. First, sex accounted for only a very small proportion of the variance in comparison to maturational rate. Therefore, reported sex differences in these behaviors probably reflect the differential distribution of the sexes along a physiologicall continuum more than a categorical difference between male and female. This concept might also apply to other behaviors not examined in this study. Second, since matuational rate was shown not to be related to verbal ability, the sex differences in verbal and spatial abilities may have very different etiologies and cannot be explained by a common set of causes, whether environmental or constitutional. Finally, rate of maturation (or its implicit physiological correlates) may play an important role in the organization of higher cortical functions." (Waber, D.P. (1976) Sex differences in cognition: A function of maturation rates. Science 192: pp. 573)

[citations removed] "Cerebral dominance may be atypical in individuals with X chromosome aneuploid states. We and others have reported that 45, X Turner syndrome females do not show the normal degree of right ear advantage in reporting dichotically presented verbal material, suggesting that their left-hemisphere based specialisation for language is attenuated. 47,XXY males show stonger leftward biases than chromosomally normal males in tests requiring the recognition of letters and the enumeration of dots presented to the left and right visual fields. These results also point to a disturbance of hemispheric organisation characterised by more than normal degrees of right hemisphere involvement in verbal and non-verbal problem solving in these individuals. Since 45,X Turner syndrome females have selective impairments of spatial abilitys the question arises whether anomalies in hemispheric organisation underlie their intellectual disorders. ...The mean age of the extra X males was 10.9 years and of the controls 10.6. Eight of the aneuploids were non-right-handed (24%) compared with 10 controls (10%)."( Netley C, Rovet J (1982) Handedness in 47 XXX males. Lancet 2: 267)

"The term 'visuospatial' is used to refer to the types of cognitive processing which are at risk in those with weak right hemisphere function, but the nature of the risk is at present underspecified. Evidence for a decline of spatial ability with increasing probability of the presence of the rs + gene was found in two large samples (Annett, 1992c). Mathematical ability is probably at risk in the rs + + genotype (Annett & Kilshaw, 1982; Annett & Manning, 1990b; Benbow, 1986) as is nonverbal reasoning (Annet & Manning, 1989 corrections by Annett, 1993b). There is evidence for weak visual processing in some dyslexics (Benton, 1991; Stein, 1991; Watson & Willows, 1993)." "Handedness is not a discrete variable, but rather a continuous one, with several possible levels of expression, along the continuous R-L distribution. The notorious inconsistency of studies of handedness arises from the treatment of a continuous variable as if it were discrete." (Annett, M., Eglinton, E., Smythe, P. (1996) Types of dyslexia and the shift to dextrality. J Child Psychology and Psychiatry 37 (2): 169)

"We found that homosexual men showed an increased prevalence of left handedness (nonCRH) compared to the general population (McCormick et al., 1987; 1990; McCormick & Witelson, 1991), and that among CRH men, homosexual men showed less functional asymmetry on a verbal dichotic listening test (McCormick & Witelson, 1990). We also observed lower spatial ability in homosexual than in heterosexual men (McCormick & Witselson, 1991). Based on these results, we suggested an association between sexual orientation and cerebral lateralization and , by inference, a neurological component to the etiology of sexual orientation. With repect to more general issues, these results suggest that early neuroendocrine events which may influence sexual orientation also may be factors in determining aspects of functional asymmetry and cognition." (Witelson SF (1991) Neural sexual mosaicism: Sexual differentiation of the human temporo-parietal region for functional asymmetry. Psychoneuroendocrinology 16: 146)

“For example, the articulators of speech (the tongue, lips, jaw) can move quite rapidly, producing easily perceived distinctions on the order of every 50-200 milliseconds. In contrast, the major articulators for sign (the hands) move relatively slowly such that the duration of an isolated sign is about 1,000 milliseconds; the duration of an average spoken word is more like 500 milliseconds. If language processing in real time has equal timing constraints for spoken and signed languages, then there is a strong pressure for signed languages to express more distinctions simulatneously. The articulatory pressures seem to work in concert with the differing capacities of the visual and auditory systems expressing simultaneous versus sequential information. This is, the visual system is sell suited for simultaneously perceiving a large amount of information, whereas the auditory system seems particularly adept at perceiving fast temporal distinctions. Thus both sign and speech have exploited the advantages of their respective modalities.” (The confluence of space and language in signed languages. (1996) Emmorey K. in Language and Space by Bloom P, Peterson MA, Nadel L, Garrett MF (eds.) pp. 173)

“Although my interests lie in the character of the preverbal conceptual system rather than of language itself, the preverbal system forms the foundation on which language rests, and it constrains what is learnable. I shall argue that preverbal conceptual representation is largely spatial in nature and that the relationship between space and language is therefore far-reaching and pervasive. It is not just that spatial terms tell us something about spatial meanings, or that spatial meanings place constraints on spatial terms. It is that many of the most basic meanings that language expresses--both semantic and syntactic--are based on spatial representations. Such a point of view will hardly be news to cognitive linguists such as Ronald Langacker or Leonard Talmy. What I hope to contribute are a few suggestions as to why language should be so structured. I will suggest that language is structured in spatially relevant ways because the meaning system of the preverbal language learner is spatially structured.” (Preverbal Prepresentation and Language (1996) Bierwisch, M. in Language and Space by Bloom P, Peterson MA, Nadel L, Garrett MF (eds.) pp. 365)

[citations removed] “With the explosion over the last decade of research on infant perception, the evidence for prelinguistic spatial concepts has become steadily more impressive. Challenging Piaget’s emphasis on the cirital role of action in the construction of spatial concepts, studies show that even very young infants are sensitive to many spatial and other physical properties of their environment. For example, habituation studies of infant perception have established that within the first few days or months of life, infants can distinguish between scenes and categorize them on the basis of spatial information such as above-below....and different orientations of an object. Studies using the related technique of time spent looking at possible versus impossible events show that by a few months of age infants also recognizes that objects continue to exist must follow a continuous trajectory and cannot pass through one another, and that objects deposited in midair will fall.” (Learning how to structure space for language: a crosslinguistic perspective (1996) Bowerman, M. in Language and Space by Bloom P, Peterson MA, Nadel L, Garrett MF (eds.) pp. 388)

"Another factor, often overlooked in the study of spatial function, may lead to erroneous conclusions. It is often assumed that spatial talent depends only on right-hemisphere function, but in fact each hemisphere contributes. Left-hemisphere lesions affect predominantly the placement of internal details while right-hemisphere lesions tend to affect external configuration. It is possible that some individuals may have high talents in one or the other function, although some are good at both. Tests of spatial function often do not distinguish these capabilities, just as handedness tests may fail to distinguish "pyramidal" and "axial" motor dominance, as was discussed in an earlier section." (Geschwind, N. & Galaburda, A.M. (1985) Cerebral Lateralization. Biological mechanisms, associations, and pathology: II. A hypothesis and a progam for research. Archives of Neurology 42(6): pp. 523)

"Although intelligence tests have been constructed to be free, overall, of sex bias, girls consistently score higher on verbal tasks and lower on visuospatial tasks than boys, especially after puberty. These differences may also be reflected in the distribution of the sexes in certain occupations (e.g., music composition and professional chess), in clinical disorders (developmental dysphasia and dyslexia, stuttering, and autism), in developmental milestones (e.g., learning to speak), and in general behavior in infancy. Two factors in male visuospacial superiority have been isolated: spacial visualization (the ability to mentally manipulate a stimulus configuration) and spatial orientation (the perception of the position and configuration of objects in sapce from the observer's viewpoint). These two factors are almost identical to those isolated in studies on the effects of localized brain damage on nonverbal cognitive performance." (Bradshaw & Nettleton 1983: 225, Human Cerebral Asymmetry)

"Compared to boys, girls speak earlier, develop larger volcabularies, can cope with more complex syntactic forms, articulate more quickly and more clearly, are more fluent, and are better readers. (Harris, 1977, 1978). ... Male superiority in nonverbal and visuaspatial functioning may have received greater attention because such superiorities are more diverse and less immediately easy to define, quantify, and observe, though as McGee (1979) notes, male superiority on tasks requiring spatial visualization and spatial orientation is among the most persistent of individual differences in the abilities literature. ... All the various factorial studies agree that spatial visualization involves the ability to mentally manipulate, rotate, twist, or invert a pictorally presented stimulus and to recognize or recall a configuration where there is movement among the internal parts of a configuation or where the object is manipulated in three-dimensional space. Imagery and mathematical ability, especially geometry and algebra, seem to be related to this. (According to Benbow & Stanley, 1980, very substantial sex differences favor boys in mathematical reasoning ability, as opposed to computational competence, in which girls may excel. Their studies showed that this effect could not be ascribed to differential course taking, educational experiences, etc.)" (Bradshaw & Nettleton 1983: 216, Human Cerebral Asymmetry)


"Kimura (1992) concluded that males tend to do better than females on mathematical reasoning, whereas females tend to better than males on arithmetic calculation. ... In our study, the effects of sex and familial sinistrality on spatial functioning varied depending on the type of spatial ability that was examined. Males outperformed females on Rotated Figures and Surface Development, two tasks that require mental manipulation of spatial objects. LHFS+ subjects outperformed LHFS- objects on Hidden Figures and Picture Completion, two tasks that relate to visual closure." (Van Strien JW, Bouma A (1995) Sex and familial sinistrality differences in cognitive abilities. Brain and Cognition 27(2):143-4)

"Cognitive functioning was assessed in 69 left-handed males and females with a positive family history of left-handedness and in 77 left-handed and 55 right-handed males and females without familial left-handedness. Compared to females, males preformed better on numerical reasoning and on two visuaospatial tasks involving spatial manipulations (Figure Rotation and Surface Development). Within the group of left-handers, the multivariate effect for Familial Sinistality was significant. Left-handers with familial left-handedness exhibited better scores on numerical reasoning, on verbal reasoning, and on two visuospatial tasks involving visual closure (Hidden Figures, Picture Completion) than did left-handers without left-handed relatives. The nonfamilial left-handers also exhibited lower scores on both inductive reasoning tasks when they were compared to their right-handed conterparts. The outcome runs contrary to the prevalent conclusion that left-handers with left-handed relatives are more likely to exhibit lower performances on visuospatial tasks than left-handers without such relatives." (Van Strien JW, Bouma A (1995) Sex and familial sinistrality differences in cognitive abilities. Brain and Cognition 27(2):137)

"Armstrong et al. (1995) suggest that this fact shifts the focus from the fine temporal organization of the acoustic modality to the spatial and action-orientated nature of language. Sentence structure, they suggest, can be understood as gestures relating to the body and to external space. Other authors (e. g. Jackendorff, 1996; Bierwisch, 1996; Johnson-Laird, 1996) have considered how some semantic and morphologic relations can be understood in terms of spatial constructs. The question arises whether spatial organisation is in some sense fundamental to syntax. This has at times been suggested--see, for example, Anderson (1971), Lyons (1977, pp. 718-724), Lyons (1995, ch. 10), Jackendorff and Landau (1992) and Deane (1993). The specific hypothesis being developed here is that there are both temporal and spatial aspects to languge, that the two are segregated (in the two hemispheres), and that the interaction between them is central to the mode of operation of the human brain." (Crow TJ, (1997) Is schizophrenia the price that Homo sapiens pays fo r language? crow TJ, (1997) Is schizophrenia the price that Homo sapiens pays for language? p. 134)

"Waber's (1976) study of early and late maturing adolescents was directly addressed to this issue. She found that adolescents with late puberty onset, regardless of phenotypic sex, had better spatial abilities than those with early pubertal onset. Spatial abilities were better than verbal ones among slow maturers, whereas verbal ones were better than spatial ones among early maturers. A subsequent replication revealed that these effects were more dramatic among middle-than lower-class subjects (Waber, Bauermeister, Cohen, Ferber, & Wolff, 1981). In her original paper, Waber (1976) also reported laterality differences between groups as indicated by a dichotic listening procedure. She found that late maturers demonstrated stonger left hemisphere biases for verbal materials than did early maturers and so attributed their ability differences in rates of maturation on hemispheric organization. Specifically, she proposed that a slower maturation rate might allow for the stronger interhemispheric differentiation necessary for good spatial skills (Levy, 1969) and typical of boys (McGlone & Davidson, 1978) to occur. Thus she concluded that maturation rate might be the mechanism responsible for sex-related differences in cognitive functioning (Maccaby & Jacklin, 1974), given that girls typically mature faster than boys. Other investigators have subsequently attempted to replicate Waber's findings, but with only partial success. In Herbst and Petersen's study (Note 1), subjects with better spatial ability were found to mature later than subjects with poorer spatial ability, but they did not differ in hemispheric lateralization. ... It was predicted that, if the Waber hypothesis is correct, children with precocious puberty will display significantly better verbal than spatial skills and individuals with delayed puberty will display significantly better spatial than verbal skills. Moreover, it is also expected that, on a task of cerebral lateral asymmetry, delayed puberty adolescents will be more lateralized than normal, whereas precocious subjects will be less lateralized than normal. ....Studies of the intellectual consequences of precocious puberty indicate that such children tend to have above-average ability, frequently in verbal skills..." (Rovet, J. (1983) Cognitive and neuropsychological test performance of persons with abnormalities of adolescent development: A test of Waber’s hypothesis. Child Development 54: pp. 941-2)

[abstract] "The nature of the relationship, if any, between performance on visuo-spatial tests in humans and circulating testosterone (T) concentrations remains controversial. We investigated possible relationships between salivary T and cortisol (C) concentrations and performance on visuo-spatial and verbal cognitive tests in a sample of healthy young adults. Among right-handers, salivary T was found to be negatively correlated with spatial performance in males, but was positively correlated with a measure of spatial visualization in females. This pattern was not evident in left-handers. Across the entire observed range of T, the relationship between spatial cognition and T was best described by an inverted quadratic function in right-handers, but not in left-handers. A significant difference in spatial accuracy was seen among right-handers tested in early vs. late morning testing sessions, in accordance with the expected diurnal change in circulating T. No significant relationships between salivary C and visuo-spatial performance were found. These results are consistent with prior literature suggesting a curvilinear relationship between spatial performance and circulating T concentrations, with intermediate levels of T being associated with better spatial functioning, but raise the possibility that hand preference may be one factor that moderates the observed relationship." (Moffat SD, Hampson E (1996) A curvilinear relationship between testosterone and spatial cognition in humans: possible influence of hand preference. Psychoneuroendocrinology 21(3):323-37)


"20 children with idiopathic precocious puberty, 27 adolescents with clinically delayed puberty, and an equivalent number of controls matched for age, sex, and IQ were given a battery of tests. These included measures of verbal and spatial abilities and a task assessing hemispheric lateralization using a dichotic listening procedure. Comparisons with matched controls revealed poorer verbal and spatial abilities for precocious males and poorer verbal, but better spatial, abilities for precocious females. Delayed developing males demonstrated superior verbal skills compared with controls, whereas delayed developing females did more poorly than controls in both verbal and spatial areas. On the dichotic task, the only group differing from controls was the delayed developing males, who demonstrated stronger lateral asymmetries. It was suggested that the present findings, which are not consistent with those of former investigations, may reflect methodological differences between studies and the disruptive influence of atypical pubertal onset on normal patterns of sex difference in cognitive functioning." (Rovet, J. (1983) Cognitive and neuropsychological test performance of persons with abnormalities of adolescent development: A test of Waber’s hypothesis. Child Development 54: pp. 941)

[citations removed] "We studied 16 adolescents with attention-deficit disorder without hyperactivity (11 males and 5 females) and 27 adolescents with attention-deficit disorder with hyperactivity (21 males and 6 females), diagnosed by the school psychologists [p.108]...Our results show that in all visuospatial tasks subjects with attention-deficit disorder performed worse than controls [p.109] ...Based on reports in the literature that suggest that attention-deficit disorder with hyperactivity may be found in association with a right-hemisphere syndrome, we investigated this hypothesis: if a right-hemisphere dysfunction could be involved in the neuropsychological substratum of attention deficit, consequently in subjects with attention-deficit disorder, this dysfunction may affect their visuospatial skills as well as their attention. Our results confirm this hypothesis: subjects with attention-deficit disorder as a group, as well as subjects with attention-deficit disorder with hyperactivity and attention-deficit disorder without hyperactivity separately, perform significantly worse than control subjects in tasks of visuospatial functions, and these results seem to support a right-hemisphere dysfuction in attention-deficit disorders. .... Metabolic imaging studies while subjects perform the same tasks as those used in our study have shown the greatest metabolic increase in the right side. It is possible that both hemispheres are necessary to carry out the visuospatial processing, but that a right-hemisphere dysfunction is necessary to evoke a deficit pattern of visuospatial abilities as that shown in our study with subjects having attention-deficit disorder. The predominant contribution of the right hemisphere to sustained spatial attention and the impairment of visuospatial abilities found in children with the developmental right-hemisphere syndrome could support this notion. [p. 112]. ... The second additional finding was that when we analyzed gender differences, we obtained results that show that certain visuospatial tasks can be gender sensitive. In all these gender-sensitive tasks, girls performed worse than boys. Specifically, females subjects having attention-deficit disorder without hyperactivity, as the controls, performed significantly worse than males on Benton Line's Orientation, and female subjects having attention-deficit disorder with hyperactivity performed significantly worse than males on WAIS Block-Design and Rey's Figure-Memory. Although these differences reveal no homogenous samples, and consequently our results must be tempered, this finding is in agreement with a positron emission tomographic study by Ernst et al who found that girls with attention-deficit hyperactivity disorder had a significantly lower cerebral metabolic rate (also more right hemisphere than left), providing external validation for our findings. ... In summary, subjects with attention-deficit disorder show visuospatial deficits as well as characteristic attention disorder. A right-hemisphere dysfunction is suspected as neuropsychological substratum of this disorder, or as a contributing factor of the neuropsychological substratum. Additionally, the visuospatial deficits in subjects with attention-deficit disorder without hyperactivity could be more severe than in subjects with attention-deficit disorder with hyperactivity. [p.113]" (Garcia-Sanchez C, Estevez-Gonzalez A, Suarez-Romero E, Junque C (1997) Right hemisphere dysfunction in subjects with attention-deficit disorder with and without hyperactivity. J Child Neurol 12(2):107-115)

[citations removed] "In general the two experiments express the well-known left hemisphere superiority for verbal processing and right hemisphere superiority for face perception. However, while the right field advantage for lexical decisions did not change throughout the menstrual cycle, the significant left field advantage for face perception in the menstrual phase disappeared during the mentrual cycle and even shifted in the prementrual phase, suggesting that hormones may influence the balance of hemispheric activation. Such influences might at least in part be responsible for more variable results with female than with male subject groups and for contradictions between different experiment studies. ... With respect to overall speed of processing the results for face decisions indicate that during menstruation and especially during the prementrual phase, the processing of such stimuli seems to be more difficult than in the middle of the cycle, where reactions were faster and fewer errors were made (see Fig. 3). This fits rather well with reports in the literature demonstrating better performance (and lower visual thresholds in midcycle, probably due to the activating effects of oestogen. However, it is difficult to compare results because of the many different ways of defining cycle phases, and the various measures and tasks employed in the literature. Our finding of faster more correct responses in midcycle is also in certain agreement with Hampson's and Hampson and Kimura's result that speed and accuracy on nonverbal tasks were better during the luteal than during the menstrual phase. If one compares the results of Experiments I and II one realizes that during the menstrual, follicular and luteal phases face decisions tended to be faster overall than lexical decisions, while during the premenstrual phase face decisions were much slower overall than the verbal ones. The premenstrual phase showed at the same time the fastest verbal and the slowest non-verbal responses of all phases of the menstrual cycle. [study done in Germany]" (Heister, G., Landis, R., Regard, M. & Schroeder-Heister, P. (1989) Shift of functional cerebral asymmetry during the menstrual cycle. Neuropsychologia 27: 877))

"The main result of our study is the linear decrease of left field superiority for face decisions, as measured from menstuation (during which pituitary and gonadal hormones are low) to what we here call the premenstrual phase, where---compared with the other phases----in particular the progesterone level should be high. That is, even with respect to asymmetry, a change takes place in the premenstrual phase. Our hypothesis that the largest asymmetry, a relatively "male pattern" of lateralization, should be found during menstruation when female sex hormones are extremely low, was supported. As compared to the menstrual phase, during the premenstrual phase 10 of the 12 subjects showed a smaller or even reversed asymmetry for this task. The reliability of our findings is also supported by the analysis of errors, which yielded the same pattern of results as reaction times, that is , a shift of asymmetry in the prementrual phase. Since the main difference was obtained between the menstrual and premenstrual phases and not between the menstrual and follicular phases, one may speculate that the result is related to progesterone, since oestrogen has one peak during the follicular phase and one during the luteal phase and should be lower during the premenstrual phase." (Heister, G., Landis, R., Regard, M. & Schroeder-Heister, P. (1989) Shift of functional cerebral asymmetry during the menstrual cycle. Neuropsychologia 27: 877-8)

"Musical talent is related to above-average spatial ability in children before and during puberty..." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in
the two sexes. Psychoneuroendocrinology 17 (1): pp. 55)

"Women with congenital adrenal hyperplasmia (CAH) have been exposed to above average androgen levels in utero. These women have been reported to display higher spatial ability than matched controls as adults (Resnick et al., 1986; but see also Ehrhardt & Meyer-Bahlburg, 1981; Reinisch, 1983). They ordinarily do not have elevated T levels as adults, but T levels of CAH women were not presented in the above-cited studies. Women with Turner's syndrome, whose gonads develop improperly and produce only minute amounts of sex homones (Nyborg, 1984), are hypoandrogenized both prenatally and in adulthood. They were found to perform poorly on spatial taks in adulthood (Nyborg & Nielson, 1981; Nyborg, 1984). Fetally nonandrogenized genetic males with androgen insensitivity syndrome (AIS) produce a normal amount of T, but their tissue is insensitive to the steroid, both pre- and post-natally. AIS patients also were found to perform poorly on spatial tasks (Nyborg, 1984). From their study with androgen-deficient men, Hier and Crowley (1982) concluded that androgens exert a permanent organizing influence on the brain before puberty or at puberty in boys. Those with hypoandrogenization in their early development did not improve on spatial tasks when treated with T as adults. Nyborg (1984) has suggested that, in addition to prenatal organizing T effects, current levels of estradiol (E2), or aromatized T, or the possibility of T antagonizing estradiol at the plasma level, influence spatial faculties. According to his General Trait Covariance Model, there is a curvilinear relationship between circulating E2 and spatial performance. This model predicts that spatial performance is highest when E2 levels are in an optimum range, below and above which spatial performance decreases. This model is in line with experimental (Broverman et al., 1968) and descriptive (Petersen, 1976) studies showing that physically androgynous persons in both sexes tend to attain higher test scores on spatial measures than do either masculine men or feminine women." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in
the two sexes. Psychoneuroendocrinology 17 (1): pp. 56)

"There is evidence that musicians are androgynous persons (Kemp, 1982; 1985; Hassler et al., 1985; Hassler & Nieschlag, 1989). Due to the relationship between spatial and musical capacities, sex hormones, particularly T as the pre-hormone for its biologically active metabolites, may contribute to the development of both musical talent and spacial ability." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in the two sexes. Psychoneuroendocrinology 17 (1): pp. 56)

"Sex differences in T levels were minimal among musical composers. T levels that differ from average values were not found in instrumentalists or in painters (Hassler, 1991a), though painters' T levels were between those of composers on the one hand and those of instrumentalists and nonmusicians on the other (Hassler, 1991a). Nonmusicians in that study had significantly higher T levels than composers." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in the two sexes. Psychoneuroendocrinology 17 (1): pp. 64)

"Our data obtained from adults allow for the hypothesis that an optimal T range may exist for the expression of creative musical behavior. This range may be at the bottom of the normal male T range and at the top of the normal female T range. T may be one component of a complex biological system contributing to musical creativity. ... The limitation given by the measurement of only one hormone must be overcome in future research in order to get more information about the hormone/behavior relationship in adolescence. For instance, E2 surges in girls occurring at age 13 should be taken into account. In women, creative musical capacities may emerge, or emerge again, in adulthood, when female hormone levels have reached the adult state. Though we have no indication of a reemergence of musical creativity in our adolescent girls, who have not yet reached the adulthood, there are clues from our study with adults (Hassler et al., 1990). Half our adult female composers began composing after puberty. General musical ability as measured with the Wing test showed some fluctuation during the course of adolescence. In 1987, when children had reached a mean age of 15.5 yr, the only significant correlation between T and Wing test scores was in girls and was positive. No other clue was found to indicate that general musical ability was related to T levels." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in the two sexes. Psychoneuroendocrinology 17 (1): pp. 66)

"T exerts its influence together with other hormones and with neurotransmitters (Hutchinson & Steimer, 1984; Whalen, 1984), and it may act on the brain as T, or by its metabolites estradiol and dihydrotestosterone." (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in the two sexes. Psychoneuroendocrinology 17 (1): pp. 66)

"The critical periods, as Dorner (1988) has argued, are not completely identical but are overlapping. The assumption that androgens influence brain differentiation during the midtrimester of gestation (Dorner, 1985; 1988) has been questioned by Money (1988, p. 23), who cited the findings of Abramovich et al. (1987) who undertook an extensive neurochemical search of tissues from fetal brains, age 14-20 wk of gestation, for evidence of receptors that would take up estrogenic, androgenic, or progentinic sex hormones. The evidence was nil. Money (1988, p. 23) concluded that the stage in development what hormones influence the differentiation of the human brain as dimorphically male or female remains to be discoverd. It may be in the third trimester of pregnancy, or it may extend through the first 3 postnatal months of age. (Hassler, M. (1992) Creative musical behavior and sex hormones: musical talent and spatial ability in the two sexes. Psychoneuroendocrinology 17 (1): pp. 66-67)