The systemizing quotient: an investigation of adults with Asperger syndrome or high-functioning autism,and normal sex differences

Systemizing is the drive to analyse systems or construct systems. A recent model of psychological sex differences suggests that this is a major dimension in which the sexes differ, with males being more drawn to systemize than females. Currently, there are no self-report measures to assess this important dimension. A second major dimension of sex differences is empathizing (the drive to identify mental states and respond to these with an appropriate emotion). Previous studies find females score higher on empathy measures. We report a new self-report questionnaire, the Systemizing Quotient (SQ), for use with adults of normal intelligence. It contains 40 systemizing items and 20 control items. On each systemizing item, a person can score 2, 1 or 0, so the SQ has a maximum score of 80 and a minimum of zero. In Study 1, we measured the SQ of n = 278 adults (114 males, 164 females) from a general population, to test for predicted sex differences (male superiority) in systemizing. All subjects were also given the Empathy Quotient (EQ) to test if previous reports of female superiority would be replicated. In Study 2 we employed the SQ and the EQ with n = 47 adults (33 males, 14 females) with Asperger syndrome (AS) or high-functioning autism (HFA), who are predicted to be either normal or superior at systemizing, but impaired at empathizing. Their scores were compared with n = 47 matched adults from the general population in Study 1. In Study 1, as predicted, normal adult males scored significantly higher than females on the SQ and significantly lower on the EQ. In Study 2, again as predicted, adults with AS/HFA scored significantly higher on the SQ than matched controls, and significantly lower on the EQ than matched controls. The SQ reveals both a sex difference in systemizing in the general population and an unusually strong drive to systemize in AS/HFA. These results are discussed in relation to two linked theories: the 'empathizing-systemizing' (E-S) theory of sex differences and the extreme male brain (EMB) theory of autism.     

Attenuation of Typical Sex Differences in 800 Adults with Autism vs. 3,900 Controls

Sex differences have been reported in autistic traits and systemizing (male advantage), and empathizing (female advantage) among typically developing individuals. In individuals with autism, these cognitive-behavioural profiles correspond to predictions from the “extreme male brain” (EMB) theory of autism (extreme scores on autistic traits and systemizing, below average on empathizing). Sex differences within autism, however, have been under-investigated. Here we show in 811 adults (454 females) with autism and 3,906 age-matched typical control adults (2,562 females) who completed the Empathy Quotient (EQ), the Systemizing Quotient-Revised (SQ-R), and the Autism Spectrum Quotient (AQ), that typical females on average scored higher on the EQ, typical males scored higher on the SQ-R and AQ, and both males and females with autism showed a shift toward the extreme of the “male profile” on these measures and in the distribution of “brain types” (the discrepancy between standardized EQ and SQ-R scores). Further, normative sex differences are attenuated but not abolished in adults with autism. The findings provide strong support for the EMB theory of autism, and highlight differences between males and females with autism.     

Regional Gray Matter Volume Is Associated with Empathizing and Systemizing in Young Adults

Empathizing is defined as the drive to identify the mental states of others for predicting their behavior and responding with an appropriate emotion. Systemizing is defined as the drive to analyze a system in terms of the rules that govern the system in order to predict its behavior. Using voxel-based morphometry and questionnaires in a large sample of normal, right-handed young adults, we investigated the regional gray matter volume (rGMV) correlates of empathizing and systemizing and additionally those of the D score, which is the difference between systemizing and empathizing, to reveal the comprehensive picture of those correlates. Negative rGMV correlates of empathizing and positive rGMV correlates of the D score (formed by the negative correlation between rGMV and empathizing), were found primarily in nodes in the default mode network, mirror neuron system, dorsal anterior cingulate cortex, and the lateral part of the prefrontal cortex together with other areas. Positive rGMV correlates of systemizing and of the D score (formed by the positive correlation between rGMV and systemizing) were found primarily in nodes in the external attention system, middle cingulate cortex, and other regions. Negative rGMV correlates of systemizing were found in an area close to the left posterior insula and putamen. These findings reconcile some previously inconsistent findings, provide other new findings and suggest that these areas contribute to empathizing–systemizing. Furthermore, the negative/positive rGMV correlates of empathizing and positive/negative rGMV correlates of systemizing overlapped substantially. This may be in line with the notion that empathizing and systemizing compete neurally in the brain.     

Testing the ‘Extreme Female Brain’ Theory of Psychosis in Adults with Autism Spectrum Disorder with or without Co-Morbid Psychosis

Introduction

Males and females in the general population differ, on average, in their drive for empathizing (higher in females) and systemizing (higher in males). People with autism spectrum disorder (ASD) show a drive for systemizing over empathizing, irrespective of sex, which led to the conceptualisation of ASD as an ‘extreme of the typical male brain’. The opposite cognitive profile, an ‘extreme of the typical female brain’, has been proposed to be linked to conditions such as psychosis and mania/hypomania.

Methods

We compared an empathizing-over-systemizing bias (for short ‘empathizing bias’) in individuals with ASD, who had experienced psychotic illness (N = 64) and who had not (N = 71).

Results

There were overall differences in the distribution of cognitive style. Adults with ASD who had experienced psychosis were more likely to show an empathizing bias than adults with ASD who had no history of psychosis. This was modulated by IQ, and the group-difference was driven mainly by individuals with above-average IQ. In women with ASD and psychosis, the link between mania/hypomania and an empathizing bias was greater than in men with ASD.

Conclusions

The bias for empathizing over systemizing may be linked to the presence of psychosis in people with ASD. Further research is needed in a variety of clinical populations, to understand the role an empathizing bias may play in the development and manifestation of mental illness.     

Testing the imprinted brain: parent-of-origin effects on empathy and systemizing

Genomic imprinting is a violation of Mendel's laws that enables selection to act on genes, depending on parent of origin, but, even more controversially, on the sex of the offspring. This study tested whether there are parent-of-origin effects on the heritability of empathy and systemizing in the general population as part of a larger question concerning the role of imprinted genes in the evolution of human cognition and behaviour. The measures tested were the Empathy and Systemizing Quotients as proxies for the related terms mentalistic and mechanistic cognition in the imprinted brain theory.To test genomic imprinting hypotheses, correlations in behavioural scores between pairs of full, maternal and paternal siblings were compared. Where scores are influenced by imprinted genes, the actual correlations between pairs of siblings will differ from those expected following classical Mendelian inheritance in a predictable way depending on what kind of imprinting is influencing the trait. These theoretical predictions were used to test the fit of the data against Mendelian and imprinting models using structural equation modeling. The imprinted brain theory proposes a trade-off between maternally influenced mentalistic cognition and paternally influenced mechanistic cognition. However, the results of this study support a model of contrasting maternal and paternal influences on strong and weak empathizing and a maternal influence on systemizing. Although the sample size was insufficient to comprehensively analyse sex-limitation models, there is some evidence that heritability of systemizing is stronger in females than in males.     

The Extreme Male Brain Theory of Autism and the Potential Adverse Effects for Boys and Girls with Autism

Autism, typically described as a spectrum neurodevelopmental disorder characterized by impairments in verbal ability and social reciprocity as well as obsessive or repetitious behaviours, is currently thought to markedly affect more males than females. Not surprisingly, this encourages a gendered understanding of the Autism Spectrum. Simon Baron-Cohen, a prominent authority in the field of autism research, characterizes the male brain type as biased toward systemizing. In contrast, the female brain type is understood to be biased toward empathizing. Since persons with autism are characterized as hyper-systemizers and hypo-empathizers, Baron-Cohen suggests that, whether they are male or female, most possess an “extreme male brain profile.” We argue that Baron-Cohen is misled by an unpersuasive gendering of certain capacities or aptitudes in the human population. Moreover, we suggest that this may inadvertently favour boys in diagnosing children with Autism Spectrum Disorders. If this is correct, it could also have rather serious consequences for treatment and services for girls (and women) on the Autism Spectrum.     

Male dominance status,female choice and mating success in the brown lemming, Lemmus trimucronatus

The objective of this study was to determine whether female brown lemmings would selectively mate with dominant conspecific males. In dyadic encounters, oestrous females paired with dominant males engaged in more frequent lordosis and contact social behaviours than those paired with subordinate males. However, the mount and thrust scores of dominant and subordinate males did not differ significantly. When females had simultaneous access to tethered dominant and subordinate males, they spent more time in close proximity to dominant males and avoided contact with subordinate males. Copulation scores were higher with dominant males. In triadic encounters with free-moving dominant and subordinate males, oestrous females spent more time near, and engaged in more sexual behaviour with, dominant males. Intermale agonistic interactions resulted in ‘privileged access’ to females by dominant males. Sexual behaviour scores were lower and there was a 10-fold increase in intermale aggression in triadic encounters between females and unfamiliar dominant and subordinate males. Both intermale agonistic interactions and female ‘choice’ behaviour accounted for the differential copulatory success of dominant males.     

Diet and cannibalism in plainfin midshipman Porichthys notatus

The macroscopic and microscopic diversity of potential food items available in the nests of plainfin midshipman Porichthys notatus were quantified and compared with items that were found in the stomach and intestine (digestive tract) of the guarding males. In this species, males occur as one of two possible reproductive morphs: guarder males that care for young and sneaker males that parasitize the courtship and care of guarder males. Although it was predicted that guarder males would have fewer feeding opportunities due to their confinement to the nest, they in fact had more food items in their digestive tracts than did sneaker males and females. Date in the breeding season (a proxy of care duration) and body condition were not correlated with the amount of food consumed by guarder males. The main type of food consumed was P. notatus embryos; 69% of all guarder males sampled had cannibalized offspring. By comparing the diet of both sexes and tactics, this study sheds light on some of the strategies designed to cope with the costs of providing parental care.     

Plasma triglyceride levels correlate with body weight,age and gender influence body weight changes in Spermophilus lateralis during prehibernation and hibernation

Our experimental groups consisted of a total 16 male (M) and 15 female (F), juvenile and adult Spermophilus lateralis. This study evaluated weight gain rate (WGR) and mass-specific rate of gain (MSRG) during prehibernation, and weight loss rate (WLR), mass-specific rate of loss (MSRL) plus changes in the levels of plasma triglyceride (TG) during hibernation in these squirrels (SQ). Between January and March, the plasma samples were obtained from 26 SQ. Plasma TG was determined enzymatically, and it averaged 189 mg% with no significant difference in gender. Correlations were observed between plasma TG and sacrificed body weight (r = 0.441, p < 0.05), and between plasma TG and MSRL (r = 0.409, p < 0.05), although plasma TG was not correlated with WLR during hibernation. Juvenile female SQ had a higher WGR than adult female SQ, but no significant difference was found between juvenile and adult males. Both juvenile males and females showed a significantly higher MSRG than adult male and female SQ. Conversely, adult male SQ had a higher WLR and MSRL than juvenile male SQ, but no significant difference was observed between adult and juvenile females. Moreover, juvenile male SQ showed a significantly lower WLR but not MSRL than juvenile females. For these animals, our results suggest that the age factor influences on WGR and MSRG during prehibernation, and also influences on WLR and MSRL during torpor.     

Revisiting Gender Differences in Somatic Symptoms of Depression: Much Ado about Nothing?

Background

Women have a higher prevalence of Major Depressive Disorder (MDD) and report more severe depressive symptoms than men. Several studies have suggested that gender differences in depression may occur because women report higher levels of somatic symptoms than men. Those studies, however, have not controlled or matched for non-somatic symptoms. The objective of this study was to examine if women report relatively more somatic symptoms than men matched on cognitive/affective symptoms.

Methods

Male and female patients receiving treatment for MDD in outpatient psychiatric clinics in New Jersey and Pennsylvania, USA were matched on Beck Depression Inventory-II (BDI-II) cognitive/affective symptom scores. Male and female BDI-II somatic symptom scores were compared using independent samples 2-tailed t-tests.

Results

Of 472 male and 1,026 female patients, there were 470 male patients (mean age = 40.1 years, SD = 15.1) and 470 female patients (mean age = 43.1 years, SD = 17.2) successfully matched on BDI-II cognitive/affective symptom scores. Somatic symptoms accounted for 35% of total BDI-II scores for male patients versus 38% for matched female patients. Female patients had somatic symptom scores on average 1.3 points higher than males (p<.001), equivalent to 4% of the total BDI-II scores of female patients. Only 5% of male patients and 7% of female patients scored 2 or higher on all BDI-II somatic symptom items.

Conclusions

Gender differences in somatic scores were very small. Thus, differences in the experience and reporting of somatic symptoms would not likely explain gender differences in depression rates and symptom severity.     

1590名农村中老年人生存质量调查分析(英文)

目的:采用SF-36量表中文版评价农村中老年人生存质量,并为提高农村中老年人的生存质量和健康水平提供科学依据和建议。方法:采用随机抽样的方法,采用面对面访谈的形式,记分方法参照国际生存质量评价计划(IQOLA)的制定标准,评价其生理和心理健康状况。结果:1590名农村中老年人男性生存质量得分高于女性。经济水平对农村中老年人的生理健康的影响大于对其心理健康的影响。配偶健在的农村中老年人的各维度得分均高于无配偶者。农村中老年人的各维度得分随教育水平的升高呈升高趋势。结论:农村中老年人的生存质量与年龄成负相关,同时也受文化程度和经济水平等多个因素的影响。因而,对农村中老年人这一弱势群体应该给予更多关注。     

The Texas rape scale

A rape scale was developed that can be used to assess male and female attitudes and reactions to rape. A series of subscales indexes sexual aggression, defense against rape, intensity of reactions toward rape, knowledge about the characteristics of rape, and personal circumtances. The scale is of potential value to investigators interested in more clearly defining sexual differences. The Texas Rape Scale (TRS) of 96 statements was administered to 261 males and 259 females to measure attitudes common to rape, sexual aggression, and defense against rape. Fifteen of the items relate to rape resistance and eleven to sexual aggression. Fifteen additional items comprise a “rape knowledge scale,” and sixteen items sample background variables. Ten of the ninety-six attitude statements measure intensity of reaction to rape. This subscale is called the Texas Rape Intensity Scale (TRIS) and was selected from a larger scale of 30 items independently judged for intensity on a nine-point scale by 57 males and 58 females. Five negative statements had a median intensity of 7.13 or greater, while the other five had a median intensity of 3.29 or less. These ten items were imbedded within the larger TRS.The Rape Resistance and Sexual Aggression scales had reliability coefficients of 0.42 and 0.56, respectively. Of the 96 items, 72 showed significant sex differences. Females scored higher on most items of the TRIS scale, and generally supported the rape resistance scale items. Males, on the other hand, favored the sexual aggression items. Individuals of both sexes scoring high on TRIS scored high on the Rape Resistance Scale, whereas those scoring low on TRIS scored high on the Sexual Aggression Scale. A factor analysis of the 96 items gave three factors: 1) a sexual aggression factor, 2) a rape rationalization factor, and 3) a punishment factor. Scores on the knowledge and background scales were not predictive of attitudes. When asked to respond to, “I would force a person of the opposite sex to have sex if there were 0% probability of being caught,” 27% of the males responded other than “strongly disagree,” whereas 6% of the females responded other than “strongly disagree.” Agreement or disagreement with this statement interacts significantly with the TRIS, Rape Resistance, and Sexual Aggression Scales.The TRS shows versatility in defining sex differences and in relating attitudes to predispositions toward reactions of intensity to rape and to rape aggression and rape resistance statements.     

Gender Differences in Perception of Romance in Chinese College Students

Women often complain that their partners are not romantic enough. This raises the question: how romance is recognized and evaluated in a love relationship? However, there has been essentially no empirical research bearing on this issue. The present set of studies examined possible gender differences in perceptions of romance and the associated neural mechanisms in Chinese college students. In Study 1, 303 participants (198 women, 105 men) were administrated a questionnaire consisting of 60 sentences and required to rate the romance level of each sentence. Results showed higher rating scores in males than females for low romance items, but not for high or medium romance items. In Study 2, 69 participants (37 women, 32 men) were recruited to judge the degree of romance in sentences presented on a computer screen one by one. Compared with females, males again showed higher scores and responded more slowly only to low romance items. In Study 3, 36 participants (18 women, 18 men) currently in love with someone were scanned with functional MRI while they did the romance judgment task from Study 2. Compared with females, greater brain activation was found for males in the frontal lobe, precentral gyrus, precuneus and parahippocampal gyrus for low romance items. The results provide the first piece of evidence for gender differences in romance perception, suggesting enhanced cognitive processing in males when evaluating the degree of romance in romantic scenes.     

Psychometric properties of the Japanese version of the Weiss Functional Impairment Rating Scale: Self-Report

The Weiss Functional Impairment Rating Scale Self-Report has been translated into nine languages and has been widely used in assessing functional impairment of adults with ADHD. This study is a psychometric validation of the WFIRS-S in Japanese. The WFIRS-S-J and other questionnaires were administered to 46 adults with attention-deficit–hyperactivity disorder (ADHD), 104 control adults, and 889 university students. ADHD diagnoses were made using the Japanese semi-structured diagnostic interview for adult ADHD, which is compatible with the DSM-5. All subscales of the WFIRS-S-J had Cronbach’s α values of around 0.80. Total scores on the WFIRS-S-J had high test–retest reliability after a 2-week interval. The total score, subscale scores, and 59 of the individual item scores of the 70 items in the WFIRS-S-J were significantly higher in the ADHD group than in the other two groups, although more than half of the items in subdomain G (risk) showed floor effects and did not reach significance. Generally WFIRS-S-J subdomain scores were moderately correlated with scores on the Japanese version of Conners’ Adult ADHD Rating Scales Self-Report subscales. WFIRS-S-J scores were also correlated (albeit more weakly; 0.31 ≤ r ≤ 0.55) with Beck Depression Inventory II total scores. The WFIRS-S-J showed acceptable psychometric properties, although further study is necessary.     

Diagnosing smallpox: would you know it if you saw it?

The intentional release of anthrax in the United States in 2001 and other recent acts of terrorism have highlighted the possibility of intentional release of smallpox by terrorists. Little is known about physicians' ability to diagnose smallpox, especially in the critical first days, when the potential for rapid control of transmission is greatest. During December 2002 and January 2003, primary care and emergency physicians at a large urban academic medical center were surveyed regarding the diagnosis and management of patients who present with vesicular rash illness. In addition to demographic and training-related questions, the questionnaire included items about perceived comfort in diagnosing and evaluating rashes, knowledge of the key differential diagnostic characteristics of chickenpox and smallpox, and the diagnostic interpretation of color photographs of patients with smallpox or chickenpox. Responses were summarized as a perceived comfort score, a differential diagnosis score, and a picture score. Of 266 eligible physicians, 178 (67%) responded. Of these, 95% thought clinicians need more education about bioterrorism; only 17% reported comfort in diagnosing smallpox. Although most physicians recognized pictures of smallpox and chickenpox, only 36% correctly answered 3 of 4 questions regarding differential diagnosis, an important aspect of identifying cases early. Those who were comfortable diagnosing rash illnesses had higher differential diagnosis scores. Strategies for bioterrorism-related training could take advantage of physicians' awareness of their own knowledge deficits.     

Few, small, and male: multiple effects of reduced nest space on the offspring of the solitary wasp, Euodynerus (Pareuodynerus) posticus (Hymenoptera: Vespidae)

The size of the preexisting wood cavities used as nests by aculeate Hymenoptera is expected to have consequences on fitness parameters such as offspring number and size. We evaluated the consequences of using small and large (three-times more voluminous) trap-nests by the solitary wasp, Euodynerus (Pareuodynerus) posticus (Herrich-Schaeffer). Following life-history and sex allocation theories, a number of non-mutually exclusive hypotheses were formulated: i.e. small nests either produce smaller or fewer offspring and/or more males, the cheaper sex. Wasps built about 28% more, but shorter brood cells in large nests, although their volume was still much higher in large nests. Adult males had smaller body size in small nests, but female size did not differ between large and small nests, possibly as an adaptive response against the future higher foraging costs of size-reduced females. Sex-ratio was often biased towards males in small nests. Mortality did not differ between large and small nests. We conclude that E.?(P.) posticus females would benefit from using larger nests, but that the sex-ratio would be probably overall unbalanced if females would not use also smaller, male-oriented tunnels.     

A controlled study of Tourette syndrome. V. Depression and mania.

To evaluate the role of depression and mania in Tourette syndrome (TS), we have examined 246 TS patients, 17 attention-deficit disorder (ADD) patients, 15 patients with ADD associated with TS, and 47 controls, using (1) the standardized National Institutes of Mental Health Diagnostic Interview Schedule questions for a life history of major depression and/or mania and (2) a modified Beck depression score for evaluation of depression at the time of the examination. The results were combined into depression, Beck, and mania scores. Among the controls, 2.1% had a depression score greater than 9, and none had a score greater than 10. Among the TS patients, 22.9% had a score greater than 9 and the scores ranged up to the maximum of 18 (P less than .0005). None of the pure ADD patients had a score greater than 6, whereas 20% of the ADD-secondary-to-TS (ADD 2(0) TS) patients had scores greater than or equal to 9. Among grade 3 TS patients, 46.6% had scores greater than or equal to 9. There were no differences in the frequency of depression in the TS patients with or without ADD. Comparable results were obtained for the Beck depression score, except that the percent with a score greater than or equal to 8 was higher for the TS patients with ADD (23.7%) than for those without ADD (9.3%). There was a good correlation between the depression score and the Beck score (r = .63), but no correlation between the ADD-with-hyperactivity (ADDH) score and either the depression score (r = .086) or the Beck score (r = .077). Among the controls, none had a mania score greater than or equal to 4, compared with 19.1% of the total TS patients (P = less than .0005), 11.8% of the ADD patients (P = .002), and 26.6% of the ADD 2(0) TS patients (P = .0005). Although some of the mania questions would be expected to be answered positively by ADDH patients, the correlation coefficient between the ADDH scores and the mania scores was only moderate (r = .29), whereas the correlation with the depression score was much higher (r = .63). There was minimal correlation between the number of tics and either the depression score (r = .267) or the Beck score (r = .193). We conclude that depression and manic-depressive symptoms are common in TS patients and are an integral part of the disorder rather than being secondary to motor or vocal tics.     

Sex and STEM Occupation Predict Autism-Spectrum Quotient (AQ) Scores in Half a Million People

This study assesses Autism-Spectrum Quotient (AQ) scores in a ‘big data’ sample collected through the UK Channel 4 television website, following the broadcasting of a medical education program. We examine correlations between the AQ and age, sex, occupation, and UK geographic region in 450,394 individuals. We predicted that age and geography would not be correlated with AQ, whilst sex and occupation would have a correlation. Mean AQ for the total sample score was m = 19.83 (SD = 8.71), slightly higher than a previous systematic review of 6,900 individuals in a non-clinical sample (mean of means = 16.94) This likely reflects that this big-data sample includes individuals with autism who in the systematic review score much higher (mean of means = 35.19). As predicted, sex and occupation differences were observed: on average, males (m = 21.55, SD = 8.82) scored higher than females (m = 18.95; SD = 8.52), and individuals working in a STEM career (m = 21.92, SD = 8.92) scored higher than individuals non-STEM careers (m = 18.92, SD = 8.48). Also as predicted, age and geographic region were not meaningfully correlated with AQ. These results support previous findings relating to sex and STEM careers in the largest set of individuals for which AQ scores have been reported and suggest the AQ is a useful self-report measure of autistic traits.     

Empathy in UK medical students: differences by gender, medical year and specialty interest

The importance of empathetic communication in the context of patient care has been suggested as a crucial element in the delivery of high-quality medical care. Although some countries have measured empathy among medical students, little is known formally about the state of affairs regarding empathy in the UK with regard to gender, medical years and speciality. This paper presents the results from a cross-sectional study that explored the relationship between undergraduate medical students' empathy scores relevant to gender, medical school year and future career ambitions. The Jefferson Scale of Physician Empathy, a self-administered questionnaire, was used for collecting data. It was decided to incorporate the scale into a web application that was only accessible through a confidential hyperlink. A total of 853 (68.2%) medical students completed the survey. Female students (n=470) scored significantly (t((819))=-6.63; 95% CI=-0.30, -0.16) higher than male students (n=351). No significant differences were observed between empathy mean scores and medical school year. Students choosing people-oriented specialities had significantly higher mean scores in comparison to students preferring technology oriented specialities. Three hypotheses were tested in this study. The hypothesis that female students would score higher than male students was supported by the results. The findings did not support the hypothesis that empathy scores decline during the medical school years. Finally, the findings did support the hypothesis that those preferring peopleoriented specialities would score higher on the empathy scale than students choosing technology oriented specialities. Some recommendations are made and the limitations of study are discussed.     

Quantitative histology of the seasonal changes in the gonads of summer whiting, Sillago ciliata

The histology of the gonads of free and captive summer whiting, Sillago ciliata , were compared to assess the potential of this fish for aquaculture. There were no qualitative differences between the free and captive males: both completed spermatogenesis through to spermiation. The captive females were non-reproductive, reaching only the vitellogenic stage before the eggs were resorbed by atresia.
A reproductive score was devised to assess reproductive potential in the comparison of the two populations. The females in the captive population had lower reproductive potentials, as shown by the score, and started development a month later than the normal free population. The captive males had higher reproductive scores than the free fish but they were also not spawning and, therefore, the higher score indicated that this potential was not realized. The score provides a standard against which experimental results can be compared and subsequently assessed.