It turns out that I just need a hug. I have what the experts call "skin hunger" or "touch starvation".

It is now a week since I landed in Canberra after cutting short a holiday in London. I came straight from the airport and obeyed the stricture of the prime minister to self-isolate (one of the new words in our global vocabulary - the other is "social-distancing").

So it's been a week for me home alone. I had initially thought that I would sneak out at the dead of night and shop just before the supermarket closed. I could dodge around the few late-night shoppers and use the self-service check-out ("self" is becoming a key word in our frightened times).

But that would break the rules. I've stayed within the four walls of the flat ever since last Sunday. On Friday, Dan Murphy's delivered wine and Woolworths delivered steak, sausage, milk and eggs.

But they can't deliver affection or physical contact. The delivery people left the food and drink on the porch.

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And we do need physical contact as much as we need sustenance for the stomach (not just that other form of physical contact but platonic, affectionate stroking).

The Nordic Cuddle website tells me: "Touch deprivation, or skin hunger as it's sometimes known, is a condition that arises when we have little or no physical contact with others." (By the way, is a Nordic Cuddle any different from an Australian one?)

Either way, there is a science behind this. According to Robin Dunbar, the professor of evolutionary psychology at Oxford University, stroking releases chemicals in the brain which trigger pleasure. They are a bit like opiates.

It comes from the time when we were primitive and ape-like and groomed each other.

"The slow stroking involved in grooming stimulates a particular set of nerves that are found only in hairy skin and are quite different to the usual nerves that convey information about pain and pressure," Professor Dunbar concluded.

"These neurons respond only to light and slow stroking. They have a direct route into the brain, where they trigger the release of endorphins."

He and researchers in Finland studied these patterns in the brain as human guinea pigs were stroked. The process is called "positron emission tomography".

The lovely conclusion?

"Light stroking of the torso triggers a massive endorphin response in the human brain, just as grooming does in monkeys and apes.

"Cuddling, with its concomitant behaviours of stroking, patting and even the occasional leafing through the hair, is the human form of primate grooming, and is designed to create and maintain our relationships."

In other words, we stroke each other, fondling our partner's hair and neck to give them pleasure, and the evolutionary gain is that we become closer to each other.

As we "self-isolate" and "socially-distance", we need to remember that conclusion.

We really do need human affection - physical affection. If we don't satisfy our emotional need through the physical means of a cuddle, we get lonely and down-hearted.

In my isolation, I know that.

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