I walked across the front of the National Gallery last night, and became one of many caught up and enchanted by Lozano-Hemmer's pavement 'magic-lantern show'. It seemed to fit the surrounding Christmas lights and the feeling of child-like enchantment I often get in the west end at this time of year (until I think about it all a bit more!).

After a while, surrounded by passing footfalls and flickering images, I realised that the installation is an even bigger box of tricks than it first appeared. The figures actually seem to respond. They beckon you or 'wake up' as you approach them, then retreat, retire, or go back to sleep as you walk away. The pre-recorded films react in various random ways, some sad or serious, some humorously, to sensors criss-crossing the concourse, creating a computerised grid. An image of this grid spectacularly zooms across the square every few minutes to drive the point home.

It's all clever stuff. It's all very spectacular. And as the high-tech equipment and security guards around the periphery remind me, it's all very expensive.

As well as playing with robotics, projections, phone links and sensors, Lozano-Hemmer also seems to enjoy playing with the idea of public surveillance. Setting up a network of surveillance, he allows us to have fun with it. Isn't this like getting into bed (and being tickled) by Orwell's Big Brother though? Surveillance, through play, becomes perhaps less threatening, but no less controlling and pervasive.

The artist wants to involve the viewer in the work and I've heard that the he quotes a couple of artists with similar concerns: The 17th century Spanish painter, Diego Velázquez, and that amazing painting Las Meninas, which positions you, the viewer, in the place of the subjects that the artist, Velasquez, depicts himself painting. As a more recent example, he quotes Tall Ships by Gary Hill. This is probably closer to Under Scan in its use of video and computer technology and involves the viewer in a similarly controlled intimacy with filmed images of other people. With three friends (two of them video artists), I made a special trip from London to Oxford to see Tall Ships, a multi-image, walk-through video installation, a few years ago. We were blown away – but quietly. Hill's minimal, finely-judged piece was moving rather than spectacular. As a result, it resonated more deeply. It avoided what we thought at the time, (as I am reminded now) was a major pitfall of some electronic and/or interactive work: that of looking rather more like an impressively-staged exhibit at a science museum and feeling rather less of an art experience – interactive or otherwise.

I first heard about Under Scan in Trafalgar Square on the radio. It has attracted the attention of the media and the artist speaks very well when interviewed about it. It's the kind of art that 'reports well'. It's popular, it is spectacular and I can't help thinking, is this media art, or art for the media (or maybe art for people so saturated by media messages that they really need an instantaneous, flickering, fast-moving "WOW!" to cut through it all and be engaged)?

– Maybe I'm just an old minimalist, but for me, perhaps less would have been not only more, but more focused.

Whatever it was, the installation at Trafalgar Square was fun. Like many others there, I was engaged. I stayed and explored the piece for quite a while. Interesting to see though, how many people got a kick out of stamping on the image of someone who was clearly not there to be offended or fight back. Perhaps in spite of our modern, sophisticated lifestyles and high-tech artworks, we are not so 'advanced' after all?

I've posted a couple of my favourites that I did kind of enjoy – in spite of my po-faced reservations!