The Visual Sensory Memory Test (VSMT) assesses sensory memory using pink-noise stimuli. These stimuli are square, with a random, cloud-like pattern of light and dark regions with characteristic spatial structure. Their 1/f spatial frequency spectrum makes them particularly well suited to the human visual system. In the classical version of the VSMT, the pink-noise stimulus is restricted to the central region by multiplying it by a Gaussian envelope. This gradually reduces contrast towards the four borders of the square, so that clear perception is possible only in the center.

We examined whether employing the Gaussian envelope affects performance. In addition, we introduced a new method for generating 1/f stimuli: a hierarchical algorithm that yields a well-identifiable stimulus for a given random seed, independent of the final image resolution. This approach facilitates comparisons between studies conducted on devices with different screen resolutions.

Thirty participants completed the VSMT with and without the Gaussian envelope. We found no significant differences between conditions. Moreover, there was no evidence of unwanted memorization strategies, such as focusing on the stimulus borders when the Gaussian envelope was omitted. Participants reported that the full-field stimuli were slightly more comfortable to view.