Cued Visual Selection (CVS) - Demo
Visual Perception Laboratory (VPL) Göttingen
In CVS experiments you are asked to identify the cued target in a crowd.
In the following examples you will see a regular array of oblique lines
At some time, a cue occurs, here a rectangular frame around one of the lines.
Can you tell to which side the cued line is tilted?
Of course, you can. This was a static example and you had plenty of time to make your decision.
Please try again and try to fixate better. (This example is easier to see than the following ones.)
Well, if you were finally able to see and identify at least some cued lines, we can make the task more difficult. (Please keep your eyes on the fixation cross.)
considerably shortened. It may require some exercise to see and identify all cued lines.
(And even if you think you could, you were perhaps not always correct.)
In the next example, we make the task even more difficult.
In fact, all lines were masked at the very same moment when the cue was shown; thus, no single line but only crosses were cued. If you nevertheless felt that you could identify some lines, you might have been systematically wrong; this artifact is discussed in one of my papers on CVS (see below).
And now, the last example.
What do the examples show?
Interestingly, the required presentation time after cue onset varies considerably along stimulus presentation and allows for conclusions on the underlying neural responses. This suggests that CVS might be a helpful tool to look into brain activities of otherwise unconscious processes.
Performance variations as in the demos were studied in detail in a number of experimental studies that were published (or will soon be published) in vpl-reports.de (open and free access).
You may have noticed that (for the reason of simpler pattern generation) the line pattern in the demo pictures does not change. This may help you to control whether your line identifications were correct or not. In true experiments, however, line patterns were refreshed in every trial. In addition, other cues than rectangular frames were used and lines were shown in slightly different configurations than in the demo pictures above, including a positional jitter in some experiments.