Autistic people may not give eye contact. They can either hear, or look, but not both. It is not a sign of guilt or unwillingness to engage.
I touch on picking between senses in these pieces:
I sometimes close my eyes to better parse the speech coming at me. I swim in sensory overwhelm. I must pick a firehose. Eyes front preserves the illusion of compliance, so I’ll stop listening.
In conversation, I listen better when not managing the sensory flood that comes with eye contact. I often close my eyes to shut out the social and sensory distractions–the relentless barrage of cues and stimulus–and focus on the words being spoken.
Avoiding eye contact is not a sign of guilt or deception.
The global view about liars is that they look away from you (avert their gaze) when they are lying. This is a false belief, which can be backed up with 40 years of research. What you will often find is that liar’s will often consciously engage in greater eye contact, because it is commonly (but mistakenly) believed that direct eye contact is a sign of truthfulness.
For these reasons, no relationship exists between eye gaze and deception.
People who do look away or avert their gaze when answering a question or when asked a question are just…thinking.