Does flexibility in perceptual organization compete with automatic grouping?

Abstract

Segregated objects can be sought simultaneously, i.e., mentally "re-grouped." Although the mechanisms underlying such "re-grouping" clearly differ from automatic grouping, it is unclear whether or not the end products of "re-grouping" and automatic grouping are the same. If they are, they would have similar impact on visual organization but would be in conflict. We compared the consequences of grouping and re-grouping on the performance cost induced by stimuli presented across hemifields. Two identical and contiguous target figures had to be identified within a display of circles and squares alternating around a fixation point. Eye tracking was used to check central fixation. The target pair could be located in the same or separate hemifields. A large cost of presenting targets across hemifields was observed. Grouping by connectedness yielded two types of target pair, connected and unconnected. Subjects prioritized unconnected pairs efficiently when prompted to do so, suggesting "re-grouping." However, unlike automatic grouping, this did not affect the cost of across-hemifield presentation. The suggestion is that re-grouping yields different outputs to automatic grouping, such that a fresh representation resulting from re-grouping complements the one resulting from automatic grouping but does not replace it. This is one step toward understanding how our mental exploration of the world ties in and coexists with ongoing perception.

Patients with Schizophrenia Do Not Preserve Automatic Grouping When Mentally Re-Grouping Figures: Shedding Light on an Ignored Difficulty

“…Yet we are usually able to compare two details from different houses, fruit piles, or trees without experiencing any noticeable difficulty. Our own results (Giersch and Rhein, 2008; van Assche et al, 2012) confirm we can attend to such details and associate them selectively.…”

“…We observed in two different studies that healthy volunteers are able to focus selectively on unrelated pairs, even when they belong to different pairs of figures. (Giersch and Rhein, 2008; van Assche et al, 2012). In van Assche et al (2012), targets were circles and squares like in the original paradigm, but they were arranged in alternation on a circle around a fixation point.…”

“…(Giersch and Rhein, 2008; van Assche et al, 2012). In van Assche et al (2012), targets were circles and squares like in the original paradigm, but they were arranged in alternation on a circle around a fixation point. Subjects decided whether the two identical shapes located one beside the other were two circles or two squares, as in the typical experiment.…”

Combined visual and motor disorganization in patients with schizophrenia

“…It is indeed striking that control participants were as efficient in the congruent and in the non-congruent conditions, both for rates of errors and for tap-sound asynchronies. This is in marked contrast with what is observed in visual perception tasks for which a performance advantage is very commonly observed when the task is directed to a unique object (or group of objects) compared to that seen when the task is directed toward distinct, non-grouped objects (Duncan, 1984; Egly et al, 1994; Beck and Palmer, 2002; Palmer and Beck, 2007; van Assche et al, 2012). But it is the case that in the present task, participants benefited from the regularity of the organization to guide motor outputs.…”

“…The most likely explanation is that healthy participants learned the correspondence between the tap pairs and the visual organization of the visual targets. In the non-congruent condition, this might have been facilitated by the fact that healthy participants are able to build a representation that binds unconnected targets together (Giersch and Rhein, 2008; van Assche et al, 2012). Inasmuch participants “re-grouped” unconnected targets, they quickly learned to expect an absence of connecters between those visual targets that were to be tapped together.…”