Sex Differences in Relative Foot Length and Perceived Attractiveness of Female Feet: Relationships among Anthropometry, Physique, and Preference Ratings

Foot size proportionate to stature is smaller in women than in men, and small feet apparently contribute to perceived physical attractiveness of females. This exploratory study investigated the sex difference in relative foot length and interrelations among foot length, physique, and foot preference ratings in samples from Austria and Canada, each comprised of 75 men and 75 women. The findings included the following lines of evidence: the sex difference in relative foot length replicated in both data sets; the magnitude of this sex effect was large. Relative foot length was smaller in young, nulliparous, and slim women. Pointed-toe and high-heel shoes were more likely worn by smaller, lighter, and slimmer women. Men reported liking women's feet in general more than vice versa. A vast majority of both men and women favored small feet in women, but large feet in men. One's own foot size appeared to correspond to evaluations of attractiveness; particularly, women with small feet preferred small feet in women in general. The preference for small feet in women was convergent across different methods of evaluating attractiveness. Directions for investigations in this emerging field of research on physical attractiveness are discussed.

The Nexus of Suicide Prevalence, Helping Behavior, Pace of Life, Affluence, and Intelligence: Contrary Results from Comparisons across Nations and within the United States

This study examined interrelations among suicide prevalence, affluence, intelligence, pace of life, and helping behavior on the level of aggregate analysis, both cross-nationally and within the USA, using four extant data sets (8, 15, and 29 countries; and 17 U.S. states) for the latter two variables. Pertaining to the association of suicide rates with pace of life, the results replicated discrepant previous findings of Lester. Across nations, suicide is more prevalent in populations living in faster environments, whereas within the USA suicide rates are higher in slower environments. Further, seen from an international perspective, there appears to be a nexus of variables, such that more people tend to commit suicide in the more affluent and faster environments which are populated by more intelligent, but less friendly, individuals. Within the USA, the direction of the correlations of suicide prevalence with these four variables is exactly reversed. Possible reasons for these opposed findings and implications for research are discussed.

Exponential Fitting of Suicide Rate and National Intelligence Estimates

Positive ecological (group-level) associations of Lynn and Vanhanen's 2002 national intelligence (IQ) estimates with the suicide rates of men and women across 85 countries and with the suicide rates of the male, female, and total elderly population across 48 Eurasian countries reported recently is extended by the finding that this ecological association was notedly better accounted for by exponential fitting than by linear fitting. This evidence implies that the effect of a shift in the national IQ on the suicide rate is proportional, not absolute. As a rule of thumb, a 5-point shift in national IQ roughly corresponds to a 50% change in the national suicide rate.

Footedness Is Associated with Self-reported Sporting Performance and Motor Abilities in the General Population

Left-handers may have strategic advantages over right-handers in interactive sports and innate superior abilities that are beneficial for sports. Previous studies relied on differing criteria for handedness classification and mostly did not investigate mixed preferences and footedness. Footedness appears to be less influenced by external and societal factors than handedness. Utilizing latent class analysis and structural equation modeling, we investigated in a series of studies (total N > 15300) associations of handedness and footedness with self-reported sporting performance and motor abilities in the general population. Using a discovery and a replication sample (ns = 7658 and 5062), Study 1 revealed replicable beneficial effects of mixed-footedness and left-footedness in team sports, martial arts and fencing, dancing, skiing, and swimming. Study 2 (n = 2592) showed that footedness for unskilled bipedal movement tasks, but not for skilled unipedal tasks, was beneficial for sporting performance. Mixed- and left-footedness had effects on motor abilities that were consistent with published results on better brain interhemispheric communication, but also akin to testosterone-induced effects regarding flexibility, strength, and endurance. Laterality effects were only small. Possible neural and hormonal bases of observed effects need to be examined in future studies.

The Beliefs in the Inheritance of Risk Factors for Suicide Scale (Birfss): Further Results on Demographic Correlates, Dimensionality, Reliability, and Validity

Convergent lines of evidence from adoption, family, geographical, immigrant, molecular genetic, surname, and twin studies of suicide point to genetic contributions to risk factors for suicidal behavior. Related mental health literacy (knowledge and beliefs) of professionals and laypersons may, however, lag behind this research progress. The purpose of this study was to further validate the 22-item Beliefs in the Inheritance of Risk Factors for Suicide Scale (BIRFSS), a novel instrument for assessing individuals' beliefs in the genetics of suicide. Data from a general population sample of 159 Austrian adults showed adequate internal scale consistency. Due to deliberate content heterogeneity, the instrument has a subscale structure, but factor analysis of items extracted a dominant first factor. BIRFSS scores were positively related to overall and specific knowledge on suicide facts (convergent validity), whereas unrelated to the Big Five personality dimensions, locus of control, social desirability, and verbal intelligence (discriminant validity). Demographic correlates of BIRFSS scores included respondents' age and religiosity (both positive ones), but not respondents' sex, educational level, or political orientation.

Patterns and Universals of Adult Romantic Attachment Across 62 Cultural Regions

As part of the International Sexuality Description Project, a total of 17,804 participants from 62 cultural regions completedthe RelationshipQuestionnaire(RQ), a self-reportmeasure of adult romanticattachment. Correlational analyses within each culture suggested that the Model of Self and the Model of Other scales of the RQ were psychometrically valid within most cultures. Contrary to expectations, the Model of Self and Model of Other dimensions of the RQ did not underlie the four-category model of attachment in the same way across all cultures. Analyses of specific attachment styles revealed that secure romantic attachment was normative in 79% of cultures and that preoccupied romantic attachment was particularly prevalent in East Asian cultures. Finally, the romantic attachment profiles of individual nations were correlated with sociocultural indicators in ways that supported evolutionary theories of romantic attachment and basic human mating strategies.

Suicidal Behavior and Psychological Distress in University Students: A 12-nation Study

This study investigated the prevalence of suicidal behavior and psychological distress in university students across 12 nations. A total of 5,572 university students from 12 countries were surveyed about suicide ideation, suicide attempts, and psychological distress by means of a self-administered questionnaire. Almost 29% of the samples reported having contemplated suicide and 7% reported attempting suicide. Of the total sample, 51.1% scored above the General Health Questionnaire-12 ≥ 3 cut-off points, 41.6% above the GHQ-12 ≥ 4 cut-off points, and 33.8% scored above the GHQ-12 ≥ 5 cut-off points. While odds of suicide ideation were elevated in Austria and the UK, reduced ORs were detected for China, Italy, Saudi Arabia, Tunisia, and Turkey. Similarly, while odds of suicide attempt were high in Jordan, Palestine, Saudi Arabia, and to some extent in Turkey, reduced ORs were observed for Austria, China, Italy, Japan and the United States. Elevated ORs for psychological distress were seen in Japan, Jordan, Palestine, Saudi Arabia, Tunisia, and Turkey but reduced ORs were noted in Austria, China, Iran, Italy, and the United States. Psychological distress was strongly associated with reports of suicide ideation and attempts. Suicide ideation, suicide attempt, and psychological distress are common in university students but their rates vary depending on the sociocultural context. Due attention should be devoted to the mental health needs of young adults enrolled in higher educational institutions and more cross-cultural research is warranted to better understand the etiology of the observed intersocietal variations in suicidal behavior and psychological distress.

Response to Comment on "Estimating the reproducibility of psychological science"

Gilbert et al. conclude that evidence from the Open Science Collaboration's Reproducibility Project: Psychology indicates high reproducibility, given the study methodology. Their very optimistic assessment is limited by statistical misconceptions and by causal inferences from selectively interpreted, correlational data. Using the Reproducibility Project: Psychology data, both optimistic and pessimistic conclusions about reproducibility are possible, and neither are yet warranted.

Effects of Initial Values and Convergence Criterion in the Two-Parameter Logistic Model When Estimating the Latent Distribution in BILOG-MG 3

Parameters of the two-parameter logistic model are generally estimated via the expectation-maximization algorithm, which improves initial values for all parameters iteratively until convergence is reached. Effects of initial values are rarely discussed in item response theory (IRT), but initial values were recently found to affect item parameters when estimating the latent distribution with full non-parametric maximum likelihood. However, this method is rarely used in practice. Hence, the present study investigated effects of initial values on item parameter bias and on recovery of item characteristic curves in BILOG-MG 3, a widely used IRT software package. Results showed notable effects of initial values on item parameters. For tighter convergence criteria, effects of initial values decreased, but item parameter bias increased, and the recovery of the latent distribution worsened. For practical application, it is advised to use the BILOG default convergence criterion with appropriate initial values when estimating the latent distribution from data.

Meta-analysis of associations between human brain volume and intelligence differences: How strong are they and what do they mean?

Positive associations between human intelligence and brain size have been suspected for more than 150 years. Nowadays, modern non-invasive measures of in vivo brain volume (Magnetic Resonance Imaging) make it possible to reliably assess associations with IQ. By means of a systematic review of published studies and unpublished results obtained by personal communications with researchers, we identified 88 studies examining effect sizes of 148 healthy and clinical mixed-sex samples (>8000 individuals). Our results showed significant positive associations of brain volume and IQ (r=.24, R(2)=.06) that generalize over age (children vs. adults), IQ domain (full-scale, performance, and verbal IQ), and sex. Application of a number of methods for detection of publication bias indicates that strong and positive correlation coefficients have been reported frequently in the literature whilst small and non-significant associations appear to have been often omitted from reports. We show that the strength of the positive association of brain volume and IQ has been overestimated in the literature, but remains robust even when accounting for different types of dissemination bias, although reported effects have been declining over time. While it is tempting to interpret this association in the context of human cognitive evolution and species differences in brain size and cognitive ability, we show that it is not warranted to interpret brain size as an isomorphic proxy of human intelligence differences.

Are tattooed adults really more aggressive and rebellious than those without tattoos?

One stereotype of people with tattoos is that they are more aggressive and rebellious than people without tattoos. However, studies examining differences in these traits between tattooed and non-tattooed individuals are dated and have returned equivocal results. To re-examine this issue, we asked 378 adults from London, UK, to complete self-report measures of aggression and rebelliousness, and to report the number of tattoos they possessed. Of this sample, 25.7% possessed at least one tattoo, with no sex difference in the distribution of tattoo status. We found that tattooed adults had significantly higher reactive rebelliousness, anger, and verbal aggression than non-tattooed adults. However, effect sizes were small and there were also no significant between-group differences in terms of proactive rebelliousness, physical aggression, and hostility. These results suggest that, while stereotypes may contain a kernel of truth, they likely present an outmoded picture of tattooed adults.

What's in a Surname? Physique, Aptitude, and Sports Type Comparisons between Tailors and Smiths

Combined heredity of surnames and physique, coupled with past marriage patterns and trade-specific physical aptitude and selection factors, may have led to differential assortment of bodily characteristics among present-day men with specific trade-reflecting surnames (Tailor vs. Smith). Two studies reported here were partially consistent with this genetic-social hypothesis, first proposed by Bäumler (1980). Study 1 (N = 224) indicated significantly higher self-rated physical aptitude for prototypically strength-related activities (professions, sports, hobbies) in a random sample of Smiths. The counterpart effect (higher aptitude for dexterity-related activities among Tailors) was directionally correct, but not significant, and Tailor-Smith differences in basic physique variables were nil. Study 2 examined two large total-population-of-interest datasets (Austria/Germany combined, and UK: N = 7001 and 20532) of men’s national high-score lists for track-and-field events requiring different physiques. In both datasets, proportions of Smiths significantly increased from light-stature over medium-stature to heavy-stature sports categories. The predicted counterpart effect (decreasing prevalences of Tailors along these categories) was not supported. Related prior findings, the viability of possible alternative interpretations of the evidence (differential positive selection for trades and occupations, differential endogamy and assortative mating patterns, implicit egotism effects), and directions for further inquiry are discussed in conclusion.

A Cross-Cultural Investigation of Suicidal Disclosures and Attitudes in Austrian and Turkish University Students

The prevalence of suicidal behavior and the nature of attitudes toward suicide differ in Austria and Turkey. To see if there were differences in disclosure, 351 Turkish and 310 Austrian students answered questions about disclosing suicidal thoughts. More Austrian than Turkish students reported suicidal ideation and believed that suicidal people disclose their plans, but suicidal disclosures were equally common in the two groups. Compared to Austria, suicidal disclosures in Turkey met with more positive social reactions that may facilitate a successful social support process. These findings imply that prevention efforts should reduce the stigma around suicidal disclosures.

Evidence of Sex-Linked Familial Transmission of Lateral Preferences for Hand, Foot, Eye, Ear, and Overall Sidedness in a Latent Variable Analysis

This study investigated the familial transmission of handedness, footedness, eyedness, earedness, and of underlying sidedness in a sample of adults (n = 592 families; 1528 individuals in total), using multi-item inventories and probabilistic methods for preference classification. Our results corroborate three classes of lateral preferences and of sidedness each, right, mixed, and left. Consistent with genetic studies, we obtained evidence of parent-of-origin and sex-of-children effects, suggesting important roles of maternal mixed preferences and of paternal left preferences. Further, parental age at conception predicted mixed preferences in the child. We recommend a trichotomous classification of lateral preferences also in future studies, and to intensify research into the genetic bases of footedness, eyedness and earedness.

Music and Suicidality

In recent years, the question whether personal suicidality is reflected in individual music preferences has been discussed. We assessed associations of preferred music genres and cumulative exposure to and rating of 50 preselected songs, including 25 suicide-related songs, with suicide risk factors in an online survey with 943 participants. Preferences for sad music were associated with high psychoticism, while fanship of music genres with predominantly joyful contents was linked to low psychoticism. There was a dose-response relationship of positive rating of suicide songs with high life satisfaction and low hopelessness. Music preferences partly reflect suicide risk factors, but enjoyment of suicide songs is negatively associated with risk factors of suicide, which may indicate a psychological defense mechanism against suicidal impulses.

Mixed-footedness is a more relevant predictor of schizotypy than mixed-handedness

Mixed-handedness was reported indicative of schizotypy, relevant to psychosis and schizophrenia. However, studies suffered from validity threats and did not systematically investigate associations with footedness. Moreover, there is a dearth of studies in the general population and it is currently untested whether widely used self-report scales measure schizotypy in a comparable way in student and community samples. The present study used two large and independent community and student samples (total N>2800) and utilized latent class analysis (LCA) for the classification of handedness and footedness. Psychometric properties and measurement equivalence of the Schizotypal Personality Questionnaire-Brief form (SPQ-B) in the two samples were also examined. We found that mixed-handedness (<6% prevalence), but also much more common mixed-footedness (25% prevalence), was specifically and similarly associated with higher schizotypy in both samples, Cohen d=0.15-0.18. Findings indicate that schizotypal traits in conjunction with mixed lateral preferences are thus more prevalent in the overall population than previously assumed, and that footedness may be the more relevant predictor of schizotypy than handedness. Findings are further consistent with evidence on neurodevelopmental instability, but also epigenetic mechanisms involving the sex chromosomes, regarding possible common causes of both mixed-handedness and psychosis-relevant traits.

Sex differences in general knowledge: meta-analysis and new data on the contribution of school-related moderators among high-school students

Research from various countries consistently reported an advantage of boys over girls in general knowledge and was also suggestive of some overall trends regarding specific domains of general knowledge that were speculated to stem from biologically differentiated interests. However, results were heterogeneous and, as of yet, had not been evaluated meta-analytically. Moreover, previous research drew on overly homogeneous high-school or undergraduate samples whose representativeness appears problematic; mostly, likely moderators, such as school type, student age or parental education, were also not directly investigated or controlled for. We provide a meta-analytical aggregation of available results regarding sex differences in general knowledge and present new data, investigating the psychometric properties of the General Knowledge Test (GKT), on which previous research primarily relied, and explored sex differences in a large and heterogeneous Austrian high-school student sample (N = 1088). The aggregated sex effect in general knowledge was of medium size in previous research, but differences in specific domains were heterogeneous across countries and only modest at best. Large sex differences in our data could be explained to a large part by school-related moderators (school type, school, student age, parental education) and selection processes. Boys had a remaining advantage over girls that was only small in size and that was consistent with the magnitude of sex differences in general intelligence. Analysis of the GKT yielded no evidence of biologically differentiated interests, but of a specific interest in the humanities among girls. In conclusion, previous research likely overestimated sex differences in general knowledge.

Analytic thinking reduces belief in conspiracy theories

Belief in conspiracy theories has been associated with a range of negative health, civic, and social outcomes, requiring reliable methods of reducing such belief. Thinking dispositions have been highlighted as one possible factor associated with belief in conspiracy theories, but actual relationships have only been infrequently studied. In Study 1, we examined associations between belief in conspiracy theories and a range of measures of thinking dispositions in a British sample (N=990). Results indicated that a stronger belief in conspiracy theories was significantly associated with lower analytic thinking and open-mindedness and greater intuitive thinking. In Studies 2-4, we examined the causational role played by analytic thinking in relation to conspiracist ideation. In Study 2 (N=112), we showed that a verbal fluency task that elicited analytic thinking reduced belief in conspiracy theories. In Study 3 (N=189), we found that an alternative method of eliciting analytic thinking, which related to cognitive disfluency, was effective at reducing conspiracist ideation in a student sample. In Study 4, we replicated the results of Study 3 among a general population sample (N=140) in relation to generic conspiracist ideation and belief in conspiracy theories about the July 7, 2005, bombings in London. Our results highlight the potential utility of supporting attempts to promote analytic thinking as a means of countering the widespread acceptance of conspiracy theories.

Evidence for general right-, mixed-, and left-sidedness in self-reported handedness, footedness, eyedness, and earedness, and a primacy of footedness in a large-sample latent variable analysis

Lateral preferences are important for the study of cerebral lateralization and may be indicative of neurobehavioral disorders, neurodevelopmental instability, and deficits in lateralization. Previous studies showed that self-reported preferences are also concordantly interrelated, suggesting a common genetic or biological origin, sidedness. However, with regard to the assessment and classification of lateral preferences, there is a dearth of psychometric studies, but a need for psychometrically validated instruments that can be reliably used in applied research. Based on three independent large samples (total N>15,100), this study investigated the psychometric properties of widely-used lateral preference scales of handedness, footedness, eyedness, and earedness. Preferences were consistently and replicably categorical, consisting of right, mixed, and left preferences each, underlining that primarily qualitative, rather than quantitative, differences differentiate lateral preferences. Right-, mixed-, and left-sidedness underlay the individual preferences, but sidedness alone could not fully explain the observed inter-relations. Footedness was the single most important indicator of sidedness. Our data were further consistent with predictions of right shift theory and corroborated a 'pull-to-concordance' in hand-foot preferences. We recommend the use of psychometrically validated scales and of a trichotomous classification of lateral preferences in future research, but conclude that handedness may be a biased indicator of underlying sidedness. Footedness needs to be examined more closely with regard to cerebral lateralization, neurodevelopmental disorders, and neurodevelopmental instability.

Associations between film preferences and risk factors for suicide: an online survey

Several studies indicate that exposure to suicide in movies is linked to subsequent imitative suicidal behavior, so-called copycat suicides, but little is currently known about whether the link between exposure to suicidal movies and suicidality is reflected in individual film preferences. 943 individuals participated in an online survey. We assessed associations between preferred film genres as well as individual exposure to and rating of 50 pre-selected films (including 25 featuring a suicide) with suicidal ideation, hopelessness, depression, life satisfaction, and psychoticism. Multiple regression analyses showed that preferences for film noir movies and milieu dramas were associated with higher scores on suicidal ideation, depression and psychoticism, and low scores on life satisfaction. Furthermore, preferences for thrillers and horror movies as well as preferences for tragicomedies, tragedies and melodramas were associated with higher scores of some of the suicide risk factors. There was also a dose-response relationship between positive rating of suicide films and higher life satisfaction. Due to the cross-sectional design of the study causality cannot be assessed. Individual film genre preferences seem to reflect risk factors of suicide, with film genres focusing on sad contents being preferred by individuals with higher scores on suicide risk factors. However, suicide movies are more enjoyed by viewers with higher life satisfaction, which may reflect a better ability to cope with such content.

Factorial structure and convergent and discriminant validity of the E (Empathy) scale

The Empathy (E) scale has been proposed as a theoretically and psychometrically more satisfying alternative to existing self-report measures of empathy. Its four scales (facets) cover both components (cognitive vs. emotional) and both reality statuses (fictitious vs. real-life) of empathy in pairwise combinations. Confirmatory factor analyses of the E-scale in an Austrian community sample (N = 794) suggested that one prior assumption, namely the mutual orthogonality of these facets, may partly need revision; particularly, the E-scale facets seemed to reflect more strongly differences in the reality statuses than in the components of empathy. Utilizing numerous informative psychological traits, the scale's convergent and discriminant validity were examined. E-scale scores were consistently predicted by sex-related and relationship-related constructs and measures of antisocial attitudes and behavior. Among the Big Five personality dimensions, openness emerged as a major positive correlate of empathy. Sex and age were demographic correlates of E-scale scores (higher in women and the younger). Findings were discussed with regards to the definition and measurement of empathy.