Epidemiology of sleep patterns and circadian typology in uruguayan children: The contribution of school shifts.

Healthy sleep is defined by the combination of adequate duration, good quality, and regular timing. In children, sleep thus depends on the interplay of individual, parental, organizational, community, and social variables, but only a few studies have addressed this issue in a comprehensive way nationwide. Using the Uruguayan nationally representative survey (Nutrition, Child Development, and Health Survey, Encuesta de Nutrición, Desarrollo Infantil y Salud, ENDIS), we present the first epidemiological characterization of chronobiological and sleep parameters in Latin American children. On average, Uruguayan urban children (n = 2437; 5-10-years old) showed quite late chronotypes (MSFsc = 03:53 ± 1:07), moderate misalignment (SJL = 1.0 ± 0.9 h), and adequate sleep duration (SDweek = 9.9 ± 1.0 h). Further, we show the substantial influence of school shift schedules on children's circadian typology and sleep patterns. Our results show that children attending the morning school shift have a higher risk of sleep problems than afternoon-school shift ones. The chronotype and sleep were earlier in morning-school shift children than in children attending the afternoon school shift. However, morning-school shift children had stronger misalignment, shorter sleep on school days, and a higher risk of chronic sleep deficit and non-healthy circadian misalignment (even worse in late chronotypes) than afternoon-shift children. This evidence points to the need of evaluating policies to reorganize school start times to prevent the negative effects that early schooling seems to have on children's sleep health, which has been neglected so far.

The Influence of Light and Physical Activity on the Timing and Duration of Sleep: Insights from a Natural Model of Dance Training in Shifts.

Environmental, social, and behavioral variables influence sleep timing and duration. Using wrist-worn accelerometers, we recorded 31 dancers (age = 22.6 ± 3.5) for 17 days and who trained either in the morning (n = 15) or in the late evening (n = 16). We estimated the dancers' daily sleep pattern: onset, end, and duration. In addition, their minutes of moderate-to-vigorous physical activity (MVPA) and mean light illuminance were also calculated daily and for the morning-shift and late-evening-shift time windows. On training days, the shifts involved differences in sleep timing, alarm-driven waking frequency, and the pattern of light exposure and MVPA duration. Sleep was strongly advanced when dancers trained in the morning and when alarms were used, while morning light had a low influence. Sleep was delayed when dancers were more exposed to light and displayed longer MVPA during the late evening. Sleep duration was strongly reduced on weekends and when alarms were used. A small reduction in sleep duration was also observed when morning illuminance was lower or when late evening MVPA was longer. Training in shifts influenced the timing of environmental and behavioral factors, which added up to shape dancers' sleep timing and duration.

Modernization, collectivism, and gender equality predict love experiences in 45 countries.

Recent cross-cultural and neuro-hormonal investigations have suggested that love is a near universal phenomenon that has a biological background. Therefore, the remaining important question is not whether love exists worldwide but which cultural, social, or environmental factors influence experiences and expressions of love. In the present study, we explored whether countries' modernization indexes are related to love experiences measured by three subscales (passion, intimacy, commitment) of the Triangular Love Scale. Analyzing data from 9474 individuals from 45 countries, we tested for relationships with country-level predictors, namely, modernization proxies (i.e., Human Development Index, World Modernization Index, Gender Inequality Index), collectivism, and average annual temperatures. We found that mean levels of love (especially intimacy) were higher in countries with higher modernization proxies, collectivism, and average annual temperatures. In conclusion, our results grant some support to the hypothesis that modernization processes might influence love experiences.

Challenged by extremely irregular school schedules, Uruguayan adolescents only set their waking time.

INTRODUCTION: Early school start times adversely influence adolescents' sleep duration. Late school start times and remote learning are associated with longer sleep durations. We leveraged a highly variable school schedule adopted after the first SARS-CoV-2 wave in Uruguay to study the influence of a hybrid mode of instruction (in-person/remote) with irregular school start times on adolescents' sleep. METHODS: Objective sleep on school nights (120 observations) was determined using accelerometry recordings of 15 high-school students (3 males 15-17 years old). We used mixed-effects regressions to explore the influence of the mode of instruction (in-person/remote) and school start time on adolescents' sleep patterns (onset, end, and duration). RESULTS: An irregular individual regime of 2-6 school days per week, either in-person or remote, and with irregular start times (range: 07:30-12:00) were observed during the studied period. Remote learning delayed sleep end by 48 ± 9 min and increased sleep duration by 36 ± 12 min. In addition, 1 h delay in school start time delayed sleep end in 36 ± 4 min and increased sleep duration in 34 ± 5 min. CONCLUSIONS: A strong linear association of the mode of instruction and the school start time with participants' sleep was observed: Only waking time was associated with both school start time and mode of instruction, and sleep duration increased when students were taught remotely and when school started later. These results add evidence to the effectiveness of delaying school start time to improve adolescents' sleep. However, these efforts may not overcome the influence of a very late circadian orientation, as observed in Uruguayan adolescents.

Bidirectional association between light exposure and sleep in adolescents.

Sleep behaviour is controlled by both circadian and homeostatic influences. Changes in both factors are related to the delayed sleep timing observed in adolescence, which also generates restrictions in their sleep duration. In addition, the circadian factor explains part of the observed influence of light on sleep duration. We recorded 15 high-school students for 23 days (vacation: 11 days; school term: 12 days) using GENEactive accelerometers. We employed a repeated-measures analysis to explore the day-to-day bidirectional association between mean light exposure and sleep behaviour across a period with extreme variability in social pressures. Sleep onset was more than 30 min earlier and sleep duration almost 20 min longer when previous day light was 10 times more intense. Light intensity had a reduction of more than 20% as sleep ended 1 hr later. Besides, sleep onset and offset were both later during vacation than on school days (almost 2 hr and 4 hr, respectively) and free days (almost 1 hr, respectively). Therefore, sleep duration was almost 2 hr longer on vacation and free days than on school days. On the other hand, light exposure intensity was twice as high during vacation days when adjusted by sleep timing. Insufficient sleep duration is a major problem for adolescents. Although we found that light exposure was associated with longer sleep duration, the influence of school start times was greater and ended up prevailing, which explained the short sleep durations observed on school days.

Sex differences in human mate preferences vary across sex ratios.

A wide range of literature connects sex ratio and mating behaviours in non-human animals. However, research examining sex ratio and human mating is limited in scope. Prior work has examined the relationship between sex ratio and desire for short-term, uncommitted mating as well as outcomes such as marriage and divorce rates. Less empirical attention has been directed towards the relationship between sex ratio and mate preferences, despite the importance of mate preferences in the human mating literature. To address this gap, we examined sex ratio's relationship to the variation in preferences for attractiveness, resources, kindness, intelligence and health in a long-term mate across 45 countries (n = 14 487). We predicted that mate preferences would vary according to relative power of choice on the mating market, with increased power derived from having relatively few competitors and numerous potential mates. We found that each sex tended to report more demanding preferences for attractiveness and resources where the opposite sex was abundant, compared to where the opposite sex was scarce. This pattern dovetails with those found for mating strategies in humans and mate preferences across species, highlighting the importance of sex ratio for understanding variation in human mate preferences.

Reading Competency, Speech Rate and Rhythm.

BACKGROUND: There is increasing evidence defining reading competency in terms of accuracy, speed and prosody, as well as interest in gaining better understanding of the interrelation as a function of prosodic features. This study aims to analyze the relationship between reading competency, in terms of accuracy and speed of written word recognition, and two attributes related to prosody in oral reading of texts: speech rate and rhythm. METHOD: Oral reading of a narrative text by 141 third and fourth grade Spanish-speaking students was analyzed using an automated acoustic speech procedure and their reading competency was assessed. RESULTS: Reading proficiency was associated with a lower proportion of the number and duration of pauses and greater regularity of syllable intervals, resulting in a higher rate of speech and higher regularity of rhythm. The reading experience improves rhythmic reading with some independence from the levels of automation achieved in written word recognition. CONCLUSIONS: The results suggest that when there is greater reading competence there is greater speed and rhythmic expressiveness; this improves with reading experience when a sufficient level of automation has been achieved in reading access.

Should I study or should I go (to sleep)? The influence of test schedule on the sleep behavior of undergraduates and its association with performance.

Sleep is crucial for college students' well-being. Although recommended sleep duration is between 7-9 hours per day, many students do not sleep that much. Scholar demands are among the causes of observed sleep deprivation in youth. We explored the influence of having a school test on previous night sleep in first-year students and the association of sleep duration and test performance. We ran two surveys in freshman students of the Universidad de la República, Montevideo, Uruguay: 1) 97 students of the School of Sciences who took the test at the same time; and 2) 252 School of Psychology students who took the test in four successive shifts. More than 1/2 of the participants (survey #1) and almost 1/3 (survey #2) reported short regular sleep duration (< 7h). In both samples, the sleep duration of the night before the test was reduced with respect to regular nights (survey #1: 2.1 ± 0.2 h, p < 0.001; survey #2: between 1.7 ± 0.4 h and 3.6 ± 0.3 h, all p < 0.001), with more than 10% of the students who did not sleep at all. In survey 2, sleep duration increased in later shifts (F (3,248) = 4.6, p = 0.004). Using logit regressions, we confirmed that sleep duration was positively related to test scores in both samples (survey #1: exp B = 1.15, p < 0.001; pseudo-R2 = 0.38; survey #2: exp B = 1.03, p < 0.001; pseudo-R2 = 0.25). Delaying test start time may prevent the reduction in sleep duration, which may also improve school performance. In addition, educational policies should include information for students about the impact of sleep on learning and of the consequences of reduced sleep duration.

Universality of the Triangular Theory of Love: Adaptation and Psychometric Properties of the Triangular Love Scale in 25 Countries.

The Triangular Theory of Love (measured with Sternberg's Triangular Love Scale - STLS) is a prominent theoretical concept in empirical research on love. To expand the culturally homogeneous body of previous psychometric research regarding the STLS, we conducted a large-scale cross-cultural study with the use of this scale. In total, we examined more than 11,000 respondents, but as a result of applied exclusion criteria, the final analyses were based on a sample of 7332 participants from 25 countries (from all inhabited continents). We tested configural invariance, metric invariance, and scalar invariance, all of which confirmed the cultural universality of the theoretical construct of love analyzed in our study. We also observed that levels of love components differ depending on relationship duration, following the dynamics suggested in the Triangular Theory of Love. Supplementary files with all our data, including results on love intensity across different countries along with STLS versions adapted in a few dozen languages, will further enable more extensive research on the Triangular Theory of Love.

Reading Competency, Speech Rate and Rhythm / Competencia Lectora, Fluidez y Ritmo

Background: There is increasing evidence defining reading competency in terms of accuracy, speed and prosody, as well as interest in gaining better understanding of the interrelation as a function of prosodic features. This study aims to analyze the relationship between reading competency, in terms of accuracy and speed of written word recognition, and two attributes related to prosody in oral reading of texts: speech rate and rhythm. Method: Oral reading of a narrative text by 141 third and fourth grade Spanish-speaking students was analyzed using an automated acoustic speech procedure and their reading competency was assessed. Results: Reading profi ciency was associated with a lower proportion of the number and duration of pauses and greater regularity of syllable intervals, resulting in a higher rate of speech and higher regularity of rhythm. The reading experience improves rhythmic reading with some independence from the levels of automation achieved in written word recognition. Conclusions: The results suggest that when there is greater reading competence there is greater speed and rhythmic expressiveness; this improves with reading experience when a sufficient level of automation has been achieved in reading access. (AU)

Antecedentes: cada vez más evidencias define la competencia lectora en términos de precisión, velocidad y prosodia; así hay interés en comprender esa relación en función de los rasgos prosódicos que se consideren. Este estudio analiza la relación entre precisión y velocidad de reconocimiento de la palabra escrita y dos atributos relacionados con la prosodia en la lectura oral de textos: la velocidad y el ritmo del habla. Método: se analizó la lectura oral de un texto narrativo de 141 estudiantes de habla hispana de tercer y cuarto grado de primaria mediante un procedimiento acústico automatizado del habla, evaluada su competencia lectora. Resultados: la competencia lectora se asocia con una menor proporción en el número y duración de las pausas y con una mayor regularidad de los intervalos silábicos, lo que produce mayor tasa de habla y una mayor regularidad del ritmo. La experiencia lectora mejora la lectura rítmica con cierta independencia de los niveles de automatización alcanzado en el reconocimiento de la palabra escrita. Conclusiones: los resultados sugieren que cuando hay una mayor competencia lectora hay mayor velocidad y expresividad rítmica; que mejora con la experiencia lectora cuando se ha logrado un nivel suficiente de automatización en el acceso lector. (AU)

Short Sleep Duration and Extremely Delayed Chronotypes in Uruguayan Youth: The Role of School Start Times and Social Constraints.

During adolescence, biological, psychosocial, and contextual factors converge in a "perfect storm" and have been put forward to explain the delay in chronotype observed at this age and the prevalence of disrupted sleep. This study provides evidence to support that chronotype and sleep patterns (particularly sleep duration) are socially constrained and to identify novel significant social predictors. Uruguayan public school activities are arranged in up to 4 shifts, creating a natural experiment to examine the effect of school timing on questionnaire-based assessments of sleep and chronotype. In this study, 268 high school students (15-18 years old) who attended school either on morning (0730 to 1130 h) or afternoon shifts (1130 h to 1530 h) responded to an adapted School Sleep Habits Survey. Students attending afternoon shifts had later chronotypes (a 1.5-h later midpoint of sleep on free days adjusted for sleep debt) than those attending the morning shift. Besides shift, evening social activities (including dinner time) were further identified as key predictors of late chronotypes, whereas age and gender were not. Sleep on school days was overall advanced and reduced with respect to weekends, and these effects were stronger in morning-shift students. Weekend sleep duration was similar between shifts, which probably caused the prevalence of reduced sleep durations (average weekly sleep duration, SDweek <8 h) to be higher in morning-shift students (almost 80%) than in afternoon-shift ones (34%). Reduced sleep duration was significantly higher in morning-shift students. In addition, age, chronotype, and dinner time became relevant determinants of sleep deficit only in the morning-shift students. Besides the important social constraint of early school start time, this is the first study to confirm the significance of other types of social pressures on both adolescents' chronotype and sleep deficit, which can be useful as potential new targets for effective policies to protect adolescent sleep.

Sex Differences in Mate Preferences Across 45 Countries: A Large-Scale Replication.

Considerable research has examined human mate preferences across cultures, finding universal sex differences in preferences for attractiveness and resources as well as sources of systematic cultural variation. Two competing perspectives-an evolutionary psychological perspective and a biosocial role perspective-offer alternative explanations for these findings. However, the original data on which each perspective relies are decades old, and the literature is fraught with conflicting methods, analyses, results, and conclusions. Using a new 45-country sample (N = 14,399), we attempted to replicate classic studies and test both the evolutionary and biosocial role perspectives. Support for universal sex differences in preferences remains robust: Men, more than women, prefer attractive, young mates, and women, more than men, prefer older mates with financial prospects. Cross-culturally, both sexes have mates closer to their own ages as gender equality increases. Beyond age of partner, neither pathogen prevalence nor gender equality robustly predicted sex differences or preferences across countries.

Contrasting Computational Models of Mate Preference Integration Across 45 Countries.

Humans express a wide array of ideal mate preferences. Around the world, people desire romantic partners who are intelligent, healthy, kind, physically attractive, wealthy, and more. In order for these ideal preferences to guide the choice of actual romantic partners, human mating psychology must possess a means to integrate information across these many preference dimensions into summaries of the overall mate value of their potential mates. Here we explore the computational design of this mate preference integration process using a large sample of n = 14,487 people from 45 countries around the world. We combine this large cross-cultural sample with agent-based models to compare eight hypothesized models of human mating markets. Across cultures, people higher in mate value appear to experience greater power of choice on the mating market in that they set higher ideal standards, better fulfill their preferences in choice, and pair with higher mate value partners. Furthermore, we find that this cross-culturally universal pattern of mate choice is most consistent with a Euclidean model of mate preference integration.

School start times matter, eveningness does not.

Morningness-Eveningness (M-E) has been associated with school performance when school activities are arranged early in the morning. This study aims to evaluate this association in 224 adolescents of a secondary school in Montevideo, Uruguay, attending either morning or afternoon shifts. Students' socio-demographic characteristics and performance indicators were similar across shifts, while afternoon-shift students exhibited later circadian preferences. After controlling for socio-demographic and other educational variables, eveningness was associated with lower grades only in morning-shift students. Our study suggests that eveningness influence on school performance is contingent on the temporal arrangement of scholar activities.