Star rating: ****

Whether it's a site-specific piece or a promenade performance, there's usually some kind of tacit demarcation between audience and performer - if it's not marked out in terms of physical space, then it's inherent in the roles we play as "watcher and watched". In recent projects, Portuguese choreographer Rui Horta has been experimenting with ways to thwart those limits. Set UP - seen, and raved about, at New Territories 2006 - teased audience expectations by frequently drawing a curtain across our field of vision, then hinting that something was happening on the other side.

One outcome of this gamesmanship was to make us question how we process information - not just during performances, but in everyday life. Now, with Scope, Horta pushes that investigation even further, offers us scenarios where personal bias - and that includes where you stand physically, as well as intellectually - can colour your perceptions. Which brings us to the green and purple squares . . . and Horta's sly opening gambit of separating the audience into gender groups before making us witnesses to the full-on roller-coaster relationship between Romeu Runa and Elisabeth Lambeck.

Just to emphasise the possibility that what we see isn't necessarily a reality, there's a hot-to-trot, gyrating overture where he and she accentuate their (already tasty) bodies with various falsies. Thereafter, we're given a deliberately complex mix of slippery truth-or-lies text, fiercely athletic and often combative dance, live video feeds that, like the mood-reflecting lighting design, are projected on to the floor - and all pitched between two seating banks that don't actually face each other directly.

So do the women see what the men see? Well, do we ever? And since love is the chameleon under scrutiny in Scope, Horta's wonderfully tricksy piece brilliantly targets our blind spots.

From yesterday's later editions.