This behavior could be attributed to a variety of factors, including but not limited to:
Introversion: Introverted individuals tend to be more comfortable with lower levels of social stimulation and can feel overwhelmed when meeting new people. They may prefer to observe and listen rather than actively participate in social interaction.
Shyness or Social Anxiety: Some people may feel intense nervousness or fear in social situations, especially when they are around people they don't know. They might avoid eye contact or stay silent to minimize their discomfort.
Autism Spectrum Disorder: Some individuals with autism may struggle with social interaction, including maintaining eye contact, understanding social cues, and engaging in conversation. It's important to remember that autism is a spectrum, and these traits can present differently in each individual.
Cultural Differences: In some cultures, direct eye contact might be considered disrespectful or inappropriate. Similarly, silence or not speaking out can also be culturally determined behavior.
Depression: People with depression often find social interactions draining and may prefer to be silent or avoid eye contact.
Selective Mutism: This is a complex childhood anxiety disorder characterized by a child's inability to speak in select social settings, such as school, even in situations where they can speak comfortably, such as at home with close family members.
It's important to consider that these are possible explanations, and the reasons for such behaviors can be unique to each individual. If these behaviors cause significant distress or interfere with daily life, it would be beneficial to seek professional help, such as a psychologist or psychiatrist, who can provide a more accurate diagnosis and treatment options.