Emotional dullness means that a person has difficulty in emotional expression or perception, may understand or express his feelings more slowly than others, or is less sensitive to emotional reactions. This may be a natural character, or it may be caused by the acquired environment or experience.

Here are some possible reasons for mental retardation:

1. Low self-esteem or emotional frustration: Some people may have feelings of resistance or fear because of their low self-esteem or emotional frustration in the past, resulting in difficulties in emotional expression or perception.

2. Lack of social experience: Some people may lack social experience and do not know how to establish good emotional ties with others or express their feelings, which may also lead to emotional dullness.

3. Excessive focus on work or career: Some people may be too focused on their own work or career, thus ignoring their personal emotional life and leading to emotional perception.

4. Lack of emotional support: Some people may lack emotional support when growing up, or live in an emotionally alienated environment, so they have no chance to learn how to express and deal with emotions, leading to emotional dullness.

If you think you are mentally retarded, you can consider seeking professional help, such as a psychological counselor or a mood therapist, who can help you understand your emotional problems and provide effective solutions.