If humans better understood dogs body language then we would have less dogs resorting to a bite when they feel stressed or threatened. We see several cues that this scared boy does not want to be touched. Signals that are asking for distance are often very subtle.
Level 1 distance Cues:
1. Dogs body is leaning away from the approaching hand.
2. Dogs paw is raised in a submissive manner.
3. Head is moving away asking for increased distance.
4. Eyes are avoiding the stranger
5. Mouth is closed, rather than open and relaxed.