There has been another round of calls for more education for hunters following yesterday's discharge without conviction of a deerstalker who accidentally shot his son.
Invercargill man Stephen Long's lawyer told the court his client had convinced himself he was looking at a deer.
NZ Deerstalkers Association president Bill O'Leary spends a lot of his time teaching hunters how to stay safe in the bush. He supports a judge's decision to let Mr Long off without a penalty for shooting his son on a hunting trip in March.
"Only the thickest of people would say Stephen has not already suffered," says Mr O'Leary.
The court heard Mr Long, who had hunted on Stewart Island 36 times, looked with his naked eye and through a scope but was convinced he saw a deer and not his 24-year-old son 20 metres away.
It's a phenomenon his lawyer described as cognitive bias and experts in human behaviour say it's a subconscious response that tricks a people into seeing what they want to see, not what's actually in front of them.
"What will happen is your mind will fill in those gaps," says human error expert Karl Bridges. "We believe those gaps could contribute to someone mistaking a deer with a human."
Mr Bridges says the cognitive bias theory explains why it's often experienced hunters that accidentally shoot a mate, not novices.
"I suppose an expert is more likely to refer to a previous incident and draw their conclusions from that to make their decision in their current situation."
It's something that's of growing concern to the association, which is trying to raise awareness among experienced hunters. It says the only way an animal can be positively identified is when you see the whole thing, not just part of it.