Temporal dynamics of decisions on spatial categories and distances do not differ

It has been proposed that spatial relations can be encoded in two different ways: categorically, where the relative position of objects can be described in prepositional terms (to the left/right, above/below, etc.) and coordinately, where a precise distance between the objects is assessed. Processing of categorical and coordinate spatial relations is believed to rely on the parvo- and magnocellular pathways or small and large receptive fields, respectively. We employed the response signal speed-accuracy trade-off procedure to obtain a description of temporal dynamics of information transfer for categorical and coordinate spatial decisions. In the two tasks the same procedure and stimuli were used, while the instructions called for different types of discrimination. We found no differences in information accrual speed between the tasks as would be expected from the parvo/magno cells or small/large receptive fields distinction. Theoretical consequences of these findings are discussed.