İsmail Önder

Psychometric properties of the Turkish version of the Composite Scale of Morningness.

The Composite Scale of Morningness is widely used and translated into several languages. The aim of the study was to present psychometric properties of Turkish version of CSM based on a sample of high school and university students. A total of 543 high school and 650 university students have participated in to the study. The internal consistency coefficient was found to be .73 (high school) and .80 (university). The test-retest reliability of the scale was .89 in high school sample and .84 in university sample. The mean CMS scores did not differ by gender in both samples. Exploratory and confirmatory factor analysis revealed that the scale is valid. As an external validation, morningness was associated with MEQ scores, sleep length, mid-point of sleep, rising and retiring time. The data obtained in the study suggested that the Turkish version of the CSM is a reliable and valid instrument to assess circadian preference in both high school and university samples.

Age and gender differences in morningness–eveningness in Turkish adolescents and young adults

The aim of this study was to analyze gender and age differences in chronotype preference in a Turkish sample using the Composite Scale of Morningness. Four thousand four hundred and twenty three participants were randomly sampled from students in Turkey. Ages ranged from 11 to 23 and the average age was 16.39 years. There was a significant influence of age and gender. After controlling for age, girls were more morning oriented with one exception: At the age of 16 years, girls had a higher evening orientation than boys, while at the age of 13, 17, and 19 boys showed higher eveningness. Turkish girls become morning oriented from the early age of 15 years onwards, while boys reported their peak of eveningness at the age of 19. This is fascinating, since it is the earliest age reported for a turn to morningness in girls compared to previous studies. Interestingly, girls perform a second turn towards eveningness between the ages of 17 and 19. Cultural background may imprint the early shift back to morningness in girls, since Turkish parenting styles are different for boys and girls with a more authoritarian parenting style for girls, e.g. girls help their mothers. Later on, enrolment in university might foster more independence and promote the drift back to eveningness.

Morningness–eveningness and the environment hypothesis – A cross-cultural comparison of Turkish and German adolescents

Individuals differ in morningness–eveningness, which is their preferred time for intellectual and physical activities. Although it is a basic human trait, cross-cultural comparisons are scarce but interesting because they help to determine the influence of exogenous factors, such as ambient temperature, climate and photoperiod. We here compare a large sample of German and Turkish adolescents (N = 26 465) by using the Composite Scale of Morningness and the Morning Affect Factor. First, we show that the Morning Affect Factor and Morningness scores are equivalent in both countries and we report country differences with Turkish adolescents scoring higher on morningness (F1,26 038 = 1293.313, p < 0.001) and in the morning affect (F1,26 038 = 133.833, p < 0.001). This fits into the environment hypothesis suggesting that populations near the equator should be more morning oriented. Meanwhile, gender differences were small and adolescents showed a lower morningness and a lower morning affect with increasing age.

Adaptation of the morningness eveningness scale for children into Turkish

Circadian rhythm refers to individuals’ preference associated with morning or evening activities. Circadian rhythm generally is measured by self reported instruments. One of these instruments is Morningness Eveningness Scale for Children (MESC). The aims of the study were to adapt MESC into Turkish, to determine psychometric properties of Turkish MESC and to assess chronotype preference in children aged from 9 to 12. A group of 515 children (4th to 6th graders) participated in the study. The explanatory factor analysis on the 10 items of the Turkish MESC revealed three orthogonal factors. Moreover, results of second order confirmatory factor analysis indicated that three factor structure of MESC explains morningness eveningness preference. The internal consistency and external validity of the Turkish MESC was sufficient and similar to previous studies. In overall, MESC is a valid and reliable instrument and can be used to assess circadian preferences in Turkish samples.

Do seasonal changes and teaching time affect academic performance of pre-service teachers?

Effects of time of day of being taught and the seasons on academic performance in students have received little attention by practitioners and researchers in the field of education. The aim of this study was to explore whether these factors were relevant to the academic success of a group of 2479 university students. The fall and spring semester grade point average (GPA) scores (a measure of academic attainment) of the students were collected. The results indicated that female students who were taught at different times of the day had different cumulative GPAs. Various factors might be responsible for this result, but the time of teaching might be one of them. It was also found that seasonal changes might affect academic achievement, since sophomore, junior and senior students had higher scores in the spring and a considerable number of students periodically obtained higher scores in this season.