Prior research has shown that the efficient use of graphical user interfaces strongly depends on human capabilities for spatial cognition. Although it is tempting to believe that moving from two- to three-dimensional user interfaces will enhance user performance through natural support for spatial memory, it remains unclear whether 3D displays provide these benefits. An experiment by Tavanti and Lind, reported at InfoVis 2001, provides the most compelling result in favour of 3D--their participants recalled the location of letters of the alphabet more effectively when using a 3D interface than when using a 2D one. The experiment reported in this paper is based on Tavanti and Lind's, but it controls some previously uncontrolled factors. The results strongly suggest that the effectiveness of spatial memory is unaffected by the presence or absence of threedimensional perspective effects in monocular static displays.