People rarely make rational decisions, an observation that applies to car ownership as much to marriage. Despite the soaring cost of owning a car, we are loath to give them up. Some of that might be down to such factors as convenience and safety — I’d rather be in my own car at 11pm than fidgeting nervously at a bus stop — but some of us can’t even bear to scrap cars that we no longer drive. Even the lure of the £1,000 bounty being offered on disused motors might not be enough to tempt richer drivers to ditch them.

The truth is, many a chariot spends its twilight years rusting in the garage because its driver refuses to acknowledge the inevitable. In this way, a car is rather like a pet: you know that the crotchety, arthritic furball welded to the armchair is unlikely to fulfil its mouse-chasing duties ever again, but you’d never contemplate sending it to the great cattery in the sky.

Blame oxytocin, otherwise known as the trust hormone. This is the chemical that a lactating mother produces as she breastfeeds her newborn. It is the basis of all bonding among humans, and has evolved primarily as a way of keeping parent and child emotionally attached through one of the longest childhoods in the animal kingdom. The hormone is also released during sex, promoting a feeling of warmth and attachment between lovers (again, a sneaky evolutionary trick to try to keep parents together, since two parents are better than one when it comes to the survival of offspring).

Unfortunately, according to Professor Paul Zak at Claremont Graduate University, who has pioneered research in this area, humans are not very discriminating when it comes to seeking things to bond to. We are unusual among mammals for our propensity to bond with strangers, and the professor has carried out experiments showing that our oxytocin levels can rise if someone we’ve never met shows trust in us (by, for example, sending us money in the post and asking for some to be returned).

This hormonal promiscuity, Zak argues, leads us to bond with inanimate objects too, including cars. He points out that we don’t need the physical presence of another person to bond to him or her — online dating is a perfect example of how trust, friendship and even love can be forged through machines rather than skin-to-skin contact. He even believes that when robots become more humanlike, we will be forced to seriously consider the issue of human-android marriages.

I suppose we trust our cars to get us from A to B, but the psychology underlying the car-driver relationship is still quite curious. It is aptly summarised in this quote, which was an attempt to understand why people name cars but not other appliances, such as fridges or lawnmowers. “I think that many of us spend a lot of time with our cars, not just driving/riding in them, but keeping them running, and counting on them to get us places,” says Ed Liebow, an anthropologist at the Battelle Center for Public Health Research in Seattle. “Important things happen to many of us in cars — relationships begin, grow stronger, end — we listen to the radio or sound system, and associate what we hear with powerful emotions. In short, our cars are not just utilitarian appliances. They occupy meaningful places in our lives. And despite being mass-produced, they are individualised.” One website, virtualvow.com, even offers the opportunity for drivers to marry their cars (although, obviously, the nuptials are not legally binding).

I would scoff at all this, were it not for the fact that my husband and I anthropomorphised our first car. His name was Spode (after the Wodehouse character), he was a mallard-green Vanden Plas 1300 and he boasted the most extraordinary gleaming chrome frontage.

According to a piece that I wrote about him in 1995, we endured eight breakdowns in 18 months. But so what! He had a walnut dash, leather seats and Wilton carpets — facilities that gave us great comfort, on repeated occasions, as we waited for the AA.

As I wrote then: “Could we really give up funny old Spode — the friendly wink of his slightly cross-eyed headlamps, the mock nobility of his not-quite Rolls-Royce grille, and a switch-laden dashboard that would look more at home in a light aircraft?”

In the end, we did. Then we acquired a Fiat Multipla. For those unfamiliar with its many charms, this particular model has been described as a “bozz-eyed swamp hog” and by the Financial Times as the “ugliest car in the world”. Some chap called Humberto Rodriguez described it thus: “It has a lot of qualities, but the problem is it looks so bad, like a toy.” Actually, he was Fiat’s head of design and therefore technically responsible for this vehicular abomination.

Sticking two fingers up to the style brigade, we fell for the Multipla’s idiosyncratic looks and practical design. It had three seats in the front, allowing baby to share the upfront motoring experience (Rosa now runs her tissue-and-crumb empire from the back, and baby No 2 has taken over in front). We have, again, become unreasonably attached to our motor (although she doesn’t have a name, and, no, I can’t really explain why the Mutipla is female, although her peculiar bulges might have something to do with it).

And what of Spode? It was love at first sight for Spode’s new owner. Which was just as well, since the door handle fell off as he drove it away.