kids don't seem to like certain vegetables, but they all are hardwired to like sweet tastes. And yet you could also imagine that one of the reasons why they may eventually grow to incorporate vegetables is because of some knowledge that vegetables might be better for them. So is there a change in the receptors, the distribution, the number, the sensitivity, et cetera, that can explain the transition from wanting to avoid vegetables to being willing to eat vegetables, simply in childhood to early development?

I want to take the question slightly differently, but I think it would illustrate the point. And I want to just use the difference between the olfactory system and the taste system to make the point. Taste system, five basic palates, sweet, sour, bitter, salt, and umami. Each of them has a predetermined identity.

We know exactly what, and valence. These are attractive. These are aversive. In the olfactory system, it's claimed that we can smell millions of different odors. Yet for the most part, none of them have an innate predetermined meaning. In the olfactory system, meaning is imposed by learning and experience. And the smell of smoke.

So I'm going to give you, I'm going to make it differently. There are a handful of the millions of odors that were claimed that you could immediately tell me these are aversive and these are attractive. Vomit. So vomit, it's not correct because I can assure you that there are cultures and societies where things which are far less appealing than vomit do not evoke an aversive reaction.

Really? Really. Sulfur would be maybe a universal. I'm not talking pheromones. Okay? Pheromones are in a different category that trigger innate responses. But nearly every other is afforded meaning by learning and experience. And that's why you like broccoli and I despise broccoli because I remember my mother forcing me to eat broccoli.

I'm so sorry. It's the same sensory experience. Yeah. Alright. This, this accommodates two important things. In the case of taste, you have neurons at every station that are for sweet, for sour, for bitter, for salty and umami. It's only five classes. So it's not going to take a lot of your brain.

If we can in fact smell a million odors and every one of those odors had to have predetermined meaning, there's not going to be enough brain just to accommodate that one sense. And so evolution in its infinite wisdom, it evolve a system where you put together a pathway and a cortex, olfactory cortex, where you have the capacity to associate every other in a specific context that now gives it the meaning.

Now let's go back to the original question then. So other than clearly plastic, mega plastic, because it's, it's fundamental basis and neural organization, but taste, we just told you that it's, you know, predetermined hardwire, but predetermined hardwire, it doesn't mean that it's not modulated by learning or experience. It only means that you are born liking sweet and disliking bitter.

And we have many examples of plasticity, beer being one example. So why do we learn to love beer? It's in coffee. It's because it has an associated gain to the system and that gain to the system, that positive valence that emerges out of that negative signal is sufficient to create that positive association.

And in the case of beer, of course, it's alcohol. The feeling good that we get after is more than sufficient to say, I want to have more of this. And in the case of coffee, of course, it's caffeine activating a whole group of neurotransmitter systems that give you that, that, that high associated with coffee.

So yes, this taste system is changeable. It's malleable and is subjected to learning and experience, but unlike the olfactory system is restricted in what you could do with it because its goal is to allow you to get nutrients and survive. The goal of the olfactory system is very different.

It's being used, not in our case, but in every animal species to, you know, identify friend versus foe, to identify mate, to identify ecological niches they want to be in. So it plays a very broad role that then requires that it be set up, organized and function in a very different type of context.

Taste is about, can we get the nutrients we need to survive? And can we ensure that we are attracted to the ones we need and we are averse to the ones that are going to kill us?