We all lie. In some form or other. There are many many interactions that could be considered lies every day.
One of the issues we have with this concept is the whole issue that comes from perception. A neuroscientist today would likely debate the concept of there being one single reality.
Reality does not exist
We know from witness statements that if people all report seeing the same thing then the witnesses have either contrived / discussed the event or been coached by a third party. That is why they separate witnesses as early as they can. We all perceive the events we experience differently to the next person. Indeed as people listen to me in training they all have their own advisor talking to them and their own filtering of the input feed they are taking from me through their own life experience system. People perceive the same sentence or slide in a presentation differently to the person they are sitting beside.
If a child is still of the age where they believes in monsters under the bed then when any conflict over the perception of events arises their actual reality can change to suit their preference for the memory.
"I did not hit my brother in the face with that wooden halberd!"
Can be a complete truth for that child depending on their age. They can literally create their own memories of the experience. Altering reality.
When my son did actually get hit in the face by the wooden halberd, there was no debate, he did not say the above. I saw it happen and the youngest was crying and bleeding! Much harder to debate. Although to be fair it was an accident as they were playing and he swung slowly to imply hitting - it was just around a corner when the youngest was running into it. Neither of them could see the other till impact. These things can just happen in play - [another post I think]
Adults may also have brain chemistry that is similar to a child of that age. Some people do actually seem to be pathalogical liars. I have come across a few in my time however the question here is what actually happens for the person. Do they lie because they are actually believing you want them to lie. In which case, are they perceiving it as a lie or the right thing to say?
It is normal for the teenager to lie and this is particularly stongly connected to their interactions with parents.
Lying as a teenager is not an especially reliable indicator of whether or not that teenager is, or will become, an honest person. A good part of teenage lying is a function of the strange amorality of the at-home self.
Effectively teens lie in the presence of their parents as they do not want parents to be in their lives, it is expected. Yet as the quote says this is not a good indicator of adult life or for that matter honesty outside the home.
Therefore, can a lie be a lie if the person saying has the perception they are not lying?