science question - sensation and perception

what is the difference between an invariant and a cue?

I know that most of you have no idea what that means, but i have an exam in a few days and this is one of the two essay questions. I'm always surprised by how knowledgeable forum ppl tend to be, so i figured hey, its worth a shot

 

invariant = real, cue = something that you pick up


like for instance, a tree is invariant, you percieve that it is there because it is there

a cue is something that surrounds something (when eskimoes go fishing they don't look for fish they look for birds, birds = cue)

that's what I think, could be totally wrong, but hey, why not take a shot at it, worst that happens is I'm wrong and someone else gives you the right answer

 

The perception of shape is independent of the size and position of the shape and also of the visual cue that defines it. The same shape can be recognized whether defined by a difference in luminance, by motion, or by texture. Experiments showed that the shape selectivity of individual cells in the macaque inferior temporal cortex did not vary with the size and position of a shape and also did not vary with the visual cue used to define the shape. This cue invariance was true for static luminance and texture cues as well as for relative motion cues--that is, for cues that are processed in ventral and dorsal visual pathways. The properties of these inferior temporal cells meet the demands of cue-invariant shape coding.