Visual Search Problem

Visual perception accomplished in our brains is a fascinating process. There are many interesting features that one comes across. One of them is the visual search problem - the objective is to identify an odd image amidst a group of distractor images in the shortest time. Put differently, certain kind of symbols are more easily recognizable when placed amidst a group of similar looking symbols whilst others are not.

For instance - symbol 'V' amidst symbol '^'s (inverted V) are very easy to spot. On the other hand, symbol 'S's are much more difficult to spot amidst symbol '2' (mirrored S).

I could personally relate to this phenomenon while solving a 3x3 Sudoku in the shortest possible time.
When I am tracking the existing entries (given entries + those that I solved), I usually take the approach of seeing the Sudoku in totality rather than scanning them by rows/columns/boxes. I have realized that this approach is quicker and saves me some precious time. I presume it is widely used technique.

So when I employ this approach, I have seen that some numerals are easier to spot (amidst the existing entries) over other numerals. For instance '7's and '1's are easiest to spot while '8's, '5's, '6's '3's are harder. To a significant extent the font style matters too. I was always wondering what is the science behind this. Now I realize the reason for this variation in the spotting time.

But I was wondering whether one could conduct experiments to evolve a set of fonts for the (Hindu Arabic) numerals for use in a Sudoku to iron out this difference in spotting time amongst the numerals? If not, then instead of using Hindu Arabic numerals in a Sudoku, can a set of 9 symbols be arrived at such that the spotting time for any symbol, when placed amidst rest (8 symbols), is similar?

References:
  • Sripati, Arun P., and Carl R. Olson. "Global image dissimilarity in macaque inferotemporal cortex predicts human visual search efficiency." The Journal of Neuroscience 30.4 (2010): 1258-1269
  • Vaidhiyan, Nidhin K., S. P. Arun, and Rajesh Sundaresan. "Active sequential hypothesis testing with application to a visual search problem." Information Theory Proceedings (ISIT), 2012 IEEE International Symposium on. IEEE, 2012

Comments