2. Abnormal sexual behavior: From the perspective of normal children's psychological development, children aged 3-5 generally begin to pay attention to the differences between the sexes, while normal boys aged 3-5 will show special interest in their genitals, be curious, and often be good at playing, but with the growth of age, their awareness of moral and social behavior norms will be enhanced, and this behavior will gradually disappear. However, students have low awareness of moral behavior norms and poor self-control, especially young or serious boys, who play with external genitalia, even regardless of venue and time. In girls, the abnormal behavior of leg pinch syndrome is found, which shows that the legs are forcibly clamped and rubbed to stimulate the external genitalia, but it is less common than boys. It is also common for students to be fond of touching and being close to classmates or teachers of the opposite sex.
3. Withdrawal behavior: Withdrawal behavior is also common in preschool children, but it gets better with age. However, the abnormal behaviors of older children with mental retardation, especially serious students, often show withdrawal behaviors, such as timidity, shyness, bowing their heads, speaking in a low voice, being afraid to associate with others, being afraid of meeting strangers, going to unfamiliar places, being too attached to their relatives, etc., while others adopt the methods of being alone and avoiding.
4. Anti-social behavior: Anti-social behavior mainly refers to behaviors that do not conform to moral norms and social norms, such as lying, truancy, stealing, cheating, deliberately making trouble, etc., which are generally seen in mild students, and more in boys. If you don't pay attention to correct guidance, you will easily develop into an antisocial personality in adulthood, and your behavior will deviate from the whole social code of conduct, or even make illegal acts that damage others' lives, property or social security, with serious consequences.
5. pica behavior: pica behavior is characterized by swallowing non-food substances such as paint, plaster, hair and dirt on toys, which leads to different digestive system problems due to different foreign bodies swallowed.
6. Don't laugh or laugh late. Normal children will laugh at 2 months and laugh loudly at 4 months. If you can't laugh until 3 months, you rarely laugh after 6 months, and you can't laugh until you are 1 year old, which is a sign of mental retardation.
7. Eye hypoplasia Generally speaking, a one-month-old baby will pay attention to the surrounding environment with his eyes, while a mentally retarded baby will not pay attention to the people or things around him.
8. Poor response to sounds, no response to sounds made by adults at the side, seems to be particularly honest. Crying less, sometimes only screaming, or crying is weak, and it is difficult to cry or cause crying to external stimuli that are easy to cause crying.
9, chewing late, feeding difficult, eating solid food is not easy to swallow and cause vomiting. Drooling is normal within 1 year old, but drooling after 1 year old should attract attention.
1. Clumsy movements. Babies like to play with their hands, and they will be able to do it after 3 to 5 months of birth, but it is not normal to still not play with their hands after 6 months or to like to put toys in their mouths when they are 2 to 3 years old. The child's movements are childish, and his feet still kick each other after learning to walk. There are many aimless activities, and adults are not clear about their children's intentions.