1- ppl from Same family -behavior and personality genes -Twin studies in same family – non same family From a scientific and genetic perspective, previous studies in Behavioural Genetics have studied by researchers on how genetics and environment can affect personality. In 1991 Lois demonstrated that there is a genetic impact on personality It was decided that the best method to adopt for this investigation was to adopt twin studies to find the correlation between identical genes and personality. This study had taken into two *roads*, which can be sipltted to studying monozygotic and dizygotic twins in a shared family and a non-shared family.Research had determined that in the same environment monozygotic twins are more likely to be have similar personalities more than the dizygotic twins .A possible explanation for this might be that identical twins genetically share traits and they are more likely to do several activities together and attend same events which lead to more similarity in personality stems from their mutual environment. This study took another perspective to find the differences in personality between monozygotic twins who were reared apart in different families. In a previous study of Bronfenbrenner (1986), it has been shown that the percentage of similarity among twins reared apart was substantially shrunken.
This conclude us to that genes can not only defind the person’s personality also family environment has a major impact on personality. 2-adopted children share personalities with their adoptive siblings Another *observer* which has drawn attention to family impact on personality , is adoption studies. Which studies those who have been adopted after a reasonable time after birth and have been reared by other parents who have not interacted with them genetically. Psychologists have shown similarity between adopted siblings who are not related to each other in some personality traits 3- culture affects personality culture psychology can provide an understanding of how people think and behave from the culture that they are surrounded with and how the cultural environment that they are living in can influence their way of thinking.*thereby* Culture is an increasingly important area in personality similarity between siblings as it is an important pattern in shaping personality and behavior.A research from $$$$$$ it has been proved that people who were born and raised in the same culture share many personality traits.
WHY SIBLINGS IN THESAME FAMILY DOSE NOT HAVE SIMILARITY IN PERSONALAITY 1. Parents trait their children differently according to their gender Another important element for dissimilarity personality in siblings inthe same family in is the gender of the child and how do parents and familyreact to each one. As it can be noticed parents basically treat their sondifferently than their daughter. 2.
The order in birth 3. Brothers and sisters are not experiencing the same life On the other hand, it can be noticed that there are many of siblingsin multi-child families related to each other share genes, homes, routines and parents, but still differ in their personalities and behaviours. Events, experiences and friends are all elements that individuals do not share with their familiesalso their birth order and gender play a larg role and can affect their attitudes and determine their personalities. Thatis why some people disagree with the theory of sharing family environment could lead to similar personalities.
Resarches on birth order carried out a research on birth orderwhich is also known as the psychological birth order andhow it can affect personalities of children while they are growing up.According to Cecileand Jules(1983) it has been remarked that older siblinghave different experiences than his later born siblings because parents usually have more expectation from their firstborn child ,as a result the oldest sibling tend to be more resposiable and overrepresented towers his studies and career.Similarly,the lastborn tend to have a strong personality and become more successful because he is encircle with many adults which are capablewith more experinces and knowledge.As Cecile and Jules(1983) stated thatyoungest children occasionally think that they are indomitable since they get considerableattention from adults around them.
As a consequence , they might not see theoutcomes of their actions and they are believed to be fearless to do risky things.Furthermore, middle-borns are known for their ability in dealingwith different situation around the. Researchers in this study find out that the differences relates firstly to parents treatment to their first and later born children.