1. IntroductionChildren develop implicit theories of gender s chemata at an early age. Soon after the age of two, they identify themselves as a member of one sex (Kohlberg, 1966; Sandnabba & Ahlberg, 1999) which they soon connect with a preference of specific behavior being 'appropriate' for either girls or boys (Martin & Ruble, 2004). Starting with kindergarten-age, children give gender-stereotyped ans wers when as ked about objects their guardians would want them to play with (Raag & Rackliff, 1998) as pa rents are known to criticize them for engaging in behavior which they cons ider to be 'appropriate' for the opposite sex (Cahill & Adams , 1997; Martin, 1995). By the age of five, children already seem to have a firm understanding of how to behave 'properly' as a boy or a girl (Martin & Ruble, 2004). This knowledge is soon to be cons idered as 'correct' behavior and also expected from others. By the age of five, gender-stereotyped attitudes start to arise and expand with increasing age while rigidity seems to decrease(Huston, 1983; Ruble & Martin, 1998). At preschool age, children's play is dominated of s ame -s ex interaction (Maccoby, 1998) as playing with peers of the oppos ite sex may result in a decreas e of popularity (Ladd, 1983; Martin, 1994). The gender-segregated play-behavior of preschoolers results from a different education and treatment of sons and daughters by guardians , specifically parents (Lindsey & Mize, 2001). Emp irical evidence could, for example, be found for toy -preferences (Leaper & Gleason, 1996; Freeman, 2007), language-us e (Leaper, Anderson, & Sanders, 1998) or gender-s tereotyped play activities (Lytton & Romney, 1991) that parents engage their children in. These parental concepts of gender-stereotyped socializat ion s eem to be also crucial for the subsequent selfsocializat ion of the child (Maccoby & Jacklin, 1974). Kanka, Wagner, Schober and Spiel (2011) revealed the s trong connection between gender-stereotyped behavior and corresponding attitudes in kindergarten students : the higher thes e attitudes , the higher the related gender-stereotyped behavior. During kindergarten-age, gender-stereotyped attitudes s ignificantly start to rise and so does gender-stereotyped behavior (Campbell, Shirley, & Candy, 2004). It was already more than 30 years ago, when Bem (1981) s tated in her Gender Schema Theory that gender-stereotyped attitudes corresponding to gender-s tereotyped behavior in kindergarten s tudents are internalized by a combination of cognitive development and social learning.2. Problem StatementFor the last 40 years , the res earch of gender-stereotyped attitudes and behavior has been of major s cientific interes t (Helwig, 1998). Even though cognitive development has been shown to affect gender -s tereotyped attitudes in children, no s tudy could be found that aimed to investigate the relationship between intelligence and gender - s tereotypy in kindergarten s tudents . In s pecific, it was the crys tallized intelligence which was of interest as this is the part of intelligence known as being determined by s ocial influences and hence modifiable (whereas the fluid intelligence is determined by genetic endowments; Cattell, 1963). Hence, the pres ent s tudy aimed to inves tigate this s pecific influence of cognitive development on gender -s tereotyped attitudes at kindergarten-age whereby the other known predetermining factors , parental education and the child's own s ex, should be reg arded in data analysis as well.3. Research QuestionsAs this s tudy aimed to inves tigate various influences on kindergarten s tudents ' gen der -stereotyped attitudes , the following research questions were examined:(1) Do boys and girls show different gender-stereotyped attitudes according to cognitive development and their parental influence in s ocialization? and(2) Is there a verifiable age effect? …