GENERALLY speaking, to enjoy the average summer blockbuster, you need to check in your brain at the door of the cinema.

But you will definitely want your noggin to be fully functional to get the most out of unusual action movie I, Robot.

Not that it's hard to follow - this isn't one of those films with more twists than a corkscrew - but because it's thought provoking stuff.

Inspired by (rather than based on) Russian writer Isaac Asimov's book of the same name, the film asks questions about free will, about at which point an intelligent being stops being something and becomes someone, about our right to have slaves, even if we believe they are lesser beings, and about the human race's apparent drive towards self destruction.

Admittedly, a lot of the questions do, at least on the surface, pertain to artificial intelligence, but you can see their roots in slavery and you will certainly have something to talk about after the film other than Will Smith's first naked scene and how cool his futuristic car is.

The whole 'having to think a bit' thing could put some action movie fans off but there are plenty of car chases, human-versus-robot battles, human escaping collapsing house and other such scenes to keep everyone happy.

The downfall of I, Robot could have been its special effects, given that the vast majority of its cast are computer generated, including one of the principal characters, the robot Sonny (Alan Tudyk).

There are one or two scenes where it's hard to forget that the humans and robots have never actually been in the same room together, indeed, that the robots have never actually 'been', in the sense of existed, at all.

This is particularly the case when Del (Will Smith) is moving through a room with 1,000 robots in it which, unfortunately, features heavily in the advertising campaign, giving the impression that the film is far naffer than it is.

But for the main part, the special effects are spot on.

Sonny is completely believable and his developing relationship with Del is at the heart of the film.

Will Smith is also a great leading man, leaving his tongue-in-cheek roles well and truly behind him for this film, in which he is charming and heroic.

An action movie with a heart and a brain - is this a new breed of summer blockbuster?