  The approximative analog system we have been discussing is different from the object-tracking system mentioned earlier (for instance, in the graham cracker study). The infant’s object-tracking system has a severely limited set size, and this is true of the adult’s tracking system as well. The analog magnitude system does not. It has also been found that infants’ success shows the ratio-dependence profile of the analog magnitude system. The fact that 6-month-old babies appear to use the same system of analog representation that adults do—although, again, their discriminations are less fine—strongly suggests that humans come equipped with an innate system that makes it possible for them to make relative size distinctions across modalities. Very recently this hypothesis has been given strong confirmation by a study showing that the analog magnitude system operates in newborn babies (Izard et al. 2009). In this study, newborns were familiarized with auditory sequences containing a fixed number of syllables and were then tested with visual-spatial images of the same or a different number of objects. Infants spontaneously associated stationary, visual-spatial arrays of 4–18 objects with auditory sequences (spoken syllables) on the basis of approximate number, providing evidence for abstract numerical representations at the very beginning of postnatal  experience.[22]