Traditional and New Principles of Perceptual Grouping

Abstract

Perceptual grouping refers to the process of determining which regions and parts of the visual scene belong together as parts of higher order perceptual units such as objects or patterns. In the early 20 th century, Gestalt psychologists identified a set of classic grouping principles which specified how some image features lead to grouping between elements given that all other factors were held constant. Modern vision scientists have expanded this list to cover a wide range of image features but have also expanded the importance of learning and other non-image factors. Unlike early Gestalt accounts which were based largely on visual demonstrations, modern theories are often explicitly quantitative and involve detailed models of how various image features modulate grouping. Work has also been done to understand the rules by which different grouping principles integrate to form a final percept. This chapter gives an overview of the classic principles, modern developments in understanding them, and new principles and the evidence for them. There is also discussion of some of the larger theoretical issues about grouping such as at what stage of visual processing it occurs and what types of neural mechanisms may implement grouping principles.

Attentional requirements in perceptual grouping depend on the processes involved in the organization

“…This is a modern grouping principle (Palmer & Rock, 1994), which states that elements that are connected by other elements tend to be grouped together, and unlike most classical grouping principles that are intrinsicbased on some property of the elements themselves (e.g., color, location, shape)-it is an extrinsic grouping principle, in which grouping of several elements is based on their relations with contextual elements (e.g., Palmer & Beck, 2007). It has been demonstrated that this principle can overcome similarity by shape, and even the effect of proximity (Brooks, 2015;Palmer & Rock, 1994;Palmer, 1999). Thus, examining attentional demands for organizations involving the principle of element connectedness would provide additional and desired information concerning this principle.…”

Common region wins the competition between extrinsic grouping cues: Evidence from a task without explicit attention to grouping

“…Perceptual organization is the architecture studio of vision, which is in charge of fitting together the pieces of the retinal mosaic to build a tidy visual experience. The seminal work of Wertheimer (1923) described the main principles of perceptual grouping that determine what regions of an image constitute perceptual units or objects (Brooks, 2015), such as proximity, similarity, common fate, symmetry, parallelism, closure or good continuation. From the proposal of Palmer (1992Palmer ( , 1999, these classic Gestalt laws are classified as intrinsic grouping cues since they are based on built-in properties of the discrete elements (e.g., their shape, position), and a new set of extrinsic grouping principles which was added based on relationships between the discrete elements and other external elements that induce them to group.…”

“…Also, grouping by connectedness is the tendency of elements that are connected by other elements to be seen as part of the same group (Palmer & Rock, 1994). Prior evidence indicates that these principles can compete effectively against some of the classic Gestalt principles (Brooks, 2015). Remarkably, the ecological rationale behind connectedness arises from the fact that several parts of an object are frequently connected to one another despite showing a visual disparity in color or form (Brooks, 2015).…”

Connection‐based and object‐based grouping in multiple‐object tracking: A developmental study

“…However, these conditions can also be organized according to the hierarchical level of grouping they seem to tap into. First, in all four of these conditions, the line segments create some kind of generic spatial grouping (based on proximity and good continuation) – a rather crude, basic type of grouping, which is probably established at a relatively low level in the visual hierarchy (Brooks, ). Second, in the two experimental conditions, the actual physical connections between the line segments and the square boxes create two connection‐based grouping conditions, which can be distinguished from the control conditions (with none or altered connecting line segments) at a somewhat more fine‐grained level of detail, given some type of actual connection is present.…”