It could be possible that the end product of both automatic grouping and re-grouping have the same status. First, it might be economical to code all types of links in the same way. Second, the importance of top-down effects and the flexibility of our visual system make this hypothesis plausible. Numerous electrophysiological studies have shown the importance of feedback connections on visual areas (Bentin & Golland,
2002; Bullier, Hupé, James, & Girard,
2001; Gilbert, Ito, Kapadia, & Westheimer,
2000; Lamme & Roelfsema,
2000). Experimental studies, on the other hand, have shown grouping to be flexible (Beck & Palmer,
2002; Giersch & Caparos,
2005; Giersch & Fahle,
2002) and to evolve with time (Kimchi,
1998). It is usually thought that the link resulting from automatic grouping is coded through direct connectivity between neurons or through building a representation that unifies the different objects (Barlow,
1972; Singer & Gray,
1995; Tsotsos, Rodriguez-Sánchez, Rothenstein, & Simine,
2008; Varela, Lachaux, Rodriguez, & Martinerie,
2001; Yu, Huang, Singer, & Nikolic,
2008). It is possible that top-down mechanisms underlying “re-grouping” allow links to be coded in the same way. If information is unified within a single representation, then representations stemming from automatic grouping and “re-grouping” would conflict, with one containing the information that two objects are grouped and the other one containing the opposite information. A similar conflict would arise in the case of coding through connectivity, inasmuch as connectivity would have to convey opposite information in the case of automatic grouping and “re-grouping.” The hypothesis that the end products of grouping and re-grouping are the same is corroborated by results with schizophrenia that suggest that there is competition between automatic grouping and re-grouping (Giersch, van Assche, Huron, & Luck,
2011). Patients with schizophrenia lose access to usual links when mentally relating separate objects, as if they alternate between mental and usual groupings. Their results show that mental re-grouping can interfere and compete with automatic grouping. Even in healthy subjects, the resistance of automatic grouping to “re-grouping” interference can been questioned. Even though we usually do not lose access to automatic grouping, our subjective experience does not necessarily reflect the way information is really processed. For example, several studies have suggested that perception only seems to be continuous but is, in fact, based on the temporal integration of successive snapshots (Hogendorn, Carlson, van Rullen, & Verstraten,
2010; van Rullen & Koch,
2003). What seems to be simultaneous and stable might as well be ever changing. This might be true also for grouping.