No one has mentioned the Bronx cheer, so, I just did. 
That’s why I asked about the meaning in Western cultures, which I am interested in - I’m assuming that it would have a meaning in any culture, but I want to know what someone is trying to say when they stick their tongue out in a Western culture.
In Maori culture it is used during the Haka which is a challenge, so it supposedly makes the face look fierce. The Haka is used to say, ‘I dare you to come and fight us’ - in almost all tribal groups, only men are allowed to do the Haka.
In my experience, outside of this traditional use, if a Maori person stuck their tongue out, it would be in the western sense.
Thanks MelCthefirst. You have satisfied my curiosity and increased my knowledge.
Just saw this ‘old’ thread and thought I’d add something.
A psychologist once told me a plausible reason for this…and a good way to assess psychological reasons behind our behaviour/actions. You must look at the behaviour before it is a ‘learned’ behaviour. This occurs in very young infants and in adults when they behave subconsciously. Her (psychologist) theory on sticking-out-tongue, was to send the message, ‘keep away from me now’. This makes sense because children often stick their tongues out when mildly upset and need time ‘alone’ to work through their immediate situation. In adults we do this (subconsciously) when we are concentrating hard on something, threading a needle for example, and being disturbed will hamper our efforts. It all made perfect sense to me.
There is one exception I have heard about (and mentioned elsewhere on this thread). I once asked an old Maori about the Haka. He explained they are not ‘sticking’ there tongue out (in the western sense), they are ‘offering’ their tongue. They are literally saying, come and cut this off, because when you are close enough to cut off my tongue you are close enough for me to kill you. I liked this story and if you watch the Haka, it does seem plausible. I also heard an explanation from a white New Zealand rugby player who suggested it meant, ‘I am going to kill you and then put this (tongue) in your missus’. I prefer the more ancient, Maori explanation:-)
My older brother’s riposte to me sticking my tongue out at him was “You’re not going to put that back in your mouth are you?”
Yet another instance of the great username/post content combo series. 
How appropriate – a Zombie thread about sticking out the tongue.
I have argued in an eminent publication that the “tongue sticking out” gesture of the Gorgoneion (face of the Gorgon) and its parallels around the world (Bes in Egypt, Humbaba in Mesopotamia, Khirtimukkha and Rahu in India, and a host of others comes from the ultimate inspiration for the image:
a bloated corpse, in which the internal decay gases cause the tongue to protrude and the eyes to bug out, among other changes
This is different from other uses of the gesture, with its juvenile/taunt implications. I’d heard the Maori explanation, but that seems to differ in intent from the gesture as used in Western Culture. The only good explanation I’ve heard for that co,mes from anthropologist Claude Levi-Strauss. Ordinarily I’m not fond of his explanations, but this one looks like it has a chance of being correct.
He believed it was derived from an infant’s pushing food out of its mouth with its tongue when it was full (or didn’t like the food).
In The Whale Rider, the young girl’s uncle explains that it was done as a threat to the enemy fighters - in essence, saying “We will kill you and then EAT you!”
That’s the understanding I always had.
Somewhat in line with the controversy over Maori portraits on stamps (way way back in the 80’s) because licking the stamp could be seen as a form of ‘eating’ the person portrayed, an insult where the intent was to honour.