Activity Of Single Units In V1 During Texture Segregation
We confirmed the MUA findings with an analysis of the activity of 85 single units, isolated with a spike-sorting method. For 59 of these cells, we also measured the activity elicited by the edge and the grey hole.
Just as was the case for the MUA, the initial single unit transient responses were similar irrespective of whether the figure or ground fell in the RF =1.2, p=0.25), but we did observe that the edge elicited a slightly stronger response than the background =2.1, p=0.04). As expected, V1 activity reflected figure-ground organization during the later, sustained response phase . Now, the edge evoked more activity than the background =5.6, p<0.001), and the figure also evoked more activity than the background =5.0, p<0.001).
Perceptual Similarity Of Local Contours Experiment 1
We investigated whether convexity, closure, and symmetry are indeed perceptual quantities to represent the perception of contour shape. Although these factors are widely known as Gestalt factors for grouping and figureground organization, it is uncertain whether the factors are the perceptual quantities that represent the contour shape in natural scenes. We determined psychophysically the multidimensional configuration that represents the perceptual shape of local contour, and analyzed whether these factors could be the configuration axes. Specifically, we performed similarity tests between a wide variety of natural contour patches in which multiple cues coexist, and performed MDS analyses. We generated the multidimensional configuration that represented the perceptual distance of local contour shapes from the similarity tests, and examined whether this arrangement agreed with the configuration that was composed of Convexity, Closure, and Symmetry. If the result showed agreement, it suggests that these factors are indeed perceptual quantities in the judgment of the shape of natural contours.
Gestalt Principles Of Perception
- Explain the figure-ground relationship
- Define Gestalt principles of grouping
- Describe how perceptual set is influenced by an individuals characteristics and mental state
In the early part of the 20th century, Max Wertheimer published a paper demonstrating that individuals perceived motion in rapidly flickering static imagesan insight that came to him as he used a childs toy tachistoscope. Wertheimer, and his assistants Wolfgang Köhler and Kurt Koffka, who later became his partners, believed that perception involved more than simply combining sensory stimuli. This belief led to a new movement within the field of psychology known as Gestalt psychology. The word gestalt literally means form or pattern, but its use reflects the idea that the whole is different from the sum of its parts. In other words, the brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways. Gestalt psychologists translated these predictable ways into principles by which we organize sensory information. As a result, Gestalt psychology has been extremely influential in the area of sensation and perception .
The concept of figure-ground relationship explains why this image can be perceived either as a vase or as a pair of faces.
Another Gestalt principle for organizing sensory stimuli into meaningful perception is proximity. This principle asserts that things that are close to one another tend to be grouped together, as illustrates.
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Dynamics Of Figureground Perception
Rubin pointed out that even if all parts of a configuration are grouped together properly, it can appear either as object or surface under certain conditions. These so-called ambiguous or reversible figures flip when, for example, the attention is directed to a specific point on the stimulus pattern. The dynamics of figureground perception due to the multivalence of the stimulus field are impressively demonstrated in a pattern shown in Fig. 4
Figure 4. A pattern which affords a never-ending fluctuation in grouping
New flowers rise from the meadow and disappear again, illustrating the vain attempt to establish a tendency toward a better and more stable percept. Apparently, the pattern allows for several groupings of equal probability and hence perception fails ever to reach a steady state. This example nicely illustrates that the visual space, as Kanizsa artfully put it, is not a static geometrical scheme, nor is it a simple transposition on the perceptual level of the topographical arrangement of the retinal stimulus, but rather should be considered the result of an extremely dynamic event.
Mary A. Peterson, in, 2019
Examples Of The Similarity Principle
GitHub uses the similarity principle in two ways on the page below. First, they use it to distinguish different sections. You can immediately tell that the grey section at the top serves a different purpose than the black section, which is also separate from and different than the blue section.
Second, they also use the color blue to distinguish links from regular text and to communicate that all blue text shares a common function.
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Where To Learn More
We cant help but to invite you, once again, to enroll in your Gestalt Psychology Course! Check its description here: .
Besides learning about the Gestalt principles and how they relate to design, you will also take away some of the best resources currently available and a consolidated list of recommended reading materials, videos, and useful links to relieve you of the task of trawling the internet, searching for that vital piece of information.
In addition to this, we have a course on Visual Perception and Design: which is particularly relevant to this law.
The Loc And Figureground Perception
One of the primary candidates for brain regions involved in figureground perception is the LOC. In recent years, this region of visual cortex, located lateral to the fusiform gyrus and extending anteriorly and ventrally, has consistently shown stronger activation in response to objects versus nonobjects . used an fMRI adaptation approach to suggest that shape, but not contour processing, is carried out in the LOC . However, it is important to note that tested contour detection, not border ownership. Contour detection is hypothesized to occur early, in V1 or V2, whereas border ownership may require LOC activation, and potentially provide feedback to V1/V2 . Experiments 1 and 2 of the current study allowed isolated measurements of border ownership while contours were held constant . The sources of the border difference ERP component were estimated to reside in ventral-posterior occipital cortex .
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Grouping Principles For Contour Integration
The principle of proximity states that the strength of grouping between two elements increases as these elements are brought nearer to each other, but how exactly does grouping strength vary as a function of their separation? As reviewed above, found that this relationship could be accurately described as a power law, whereas employed an exponential model, consistent with random-walk models of contour formation . However, also noted that a power law model could fit their data equally well and found that the proximity cue was approximately scale-invariant: Scaling all distances by the same factor did not affect results. Since the power law is the only perfectly scale-invariant distribution, this last result adds strength to the power-law model of proximity, which has been used in subsequent studies .
In sum, the convergence between psychophysics and ecological statistics is compelling: Ecologically, proximity follows a power law and exhibits scale invariance, and these properties are mirrored by the psychophysical results. Thus, we have a strong indication that the human perceptual system is optimally tuned for the ecological statistics of proximity cues in natural scenes.
4.2.2 Good continuation
Example of stimuli devised by to probe the role of good continuation in contour integration .
Models of good continuation. Cocircularity support neighborhood . Association field .
The Swinging Pendulum Of Gestalt History
and his fellow-pioneers of the Berlin school of Gestalt psychology arrived at some far-reaching conclusions causing a true revolution in psychology, philosophy, and neighboring disciplines . Demonstrating a case where the phenomenological experience was clearly not composed of more elementary sensations, they concluded that structured wholes or Gestalten, rather than sensations, must be the primary units of mental life. They argued that the contents of awareness were not produced from associations or combinations between sensations. The whole is not only more than the sum of the parts, it is different because it has whole-properties that determine the part-properties as much as the other way around . From the very beginning, these Gestalts were assumed to arise on the basis of continuous whole-processes in the brain, involving the entire optical sector from retina to cortex.
The discovery of single neurons being tuned to primitive stimulus attributes in the 1950s led to a predominantly atomistic approach in neuroscience, and around the same time, computers models appeared to provide testable, mechanistic accounts of mental operations. Although the Gestalt line of work continued in relatively isolated corners of science , the mainstream around that time was very much non-Gestaltist, if not anti-Gestaltist.
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Stimulus Selection And Presentation
Based on the three indices, Convex, Closure, and Symmetry, we selected 105 patches from more than 10,000 patches taken from BFGD. Before the selection, we excluded patches that match at least one of the following conditions: contours crossed each other , a whole object was visible, or contours were packed so that it was difficult to assess the direction of figure. The second and third conditions were tested by the visual inspection of three people who were familiar with the dataset and did not participate in the experiments.
What Is Figure Ground Perception In Psychology
Figureground organization is a type of perceptual grouping that is a vital necessity for recognizing objects through vision. In Gestalt psychology it is known as identifying a figure from the background. For example, words on a printed paper are seen as the “figure,” and the white sheet as the “background”.
Similarly, why is figure ground perception important? Figure–ground perception is an important aspect of visual processing that allows children to understand what they see an important brain function that affects everything from learning to read to solving puzzles.
Consequently, what is an example of Figure ground perception?
Figure–ground perception holds that we tend to separate images into figure, or object, and ground, or background. Some common examples include the famous image of the old woman and the young lady and the depiction of the white vase that can also be perceived as two faces.
What is figure ground principle?
The figure is the text itself and the ground the paper on which the text sits. The law of Figure/Ground states that we can distinguish an object from background . This rule shows that when we look at a design, we perceive the figure from the ground distinctly.
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The Law Of Common Fate
The law of Common Fate says that we perceive shapes as lines moving along the smoothest path. For example, we look at grouped elements and see them as moving in a similar direction.
Lets see this in action. If youve got a piece of paper handy, draw seven or eight circles in a line beside each other. Above two of them, put a little arrowhead. Now, notice that these two circles are different from the others, but in the same way. The others are staying put, but the arrowheaded circles are going somewhere ; they share a common fate.
Note: The elements do not have to be moving , but they must suggest motion for this law to work in your designs.
Designing with the Law of Common Fate in Mind – The law of Common Fate plays an important role in design, for example, with nested menus and content. Take the example of LinkedIn . LinkedIn have used the law of common fate to build a relationship between sub-menus. When you move over a menu item, the sub-menu item moves in the same direction as the last. This creates a link between sub-menus in the minds of the users.
Context Integration In Illusory Contours
Illusory contours were among the earliest demonstrations of perceptual organization . Gestalt theory explains these contours by completion processes in the visual cortex. Initially, Sillito and colleagues recorded single neuron responses in cat primary visual cortex and found no evidence for illusory contour signals. Neurons that clearly responded to low-contrast figures were silent when illusory figures with the same perceived contrast were presented. However, recording from an area one level higher, namely in V2 of the monkey visual cortex, found illusory contour responses in about one third of the recorded neurons. The stereotyped nature of the responses to repeated stimulation and their short latency indicated that the observed responses were stimulus-driven rather than resulting from higher-level, cognitive predictions as hypothesized by .
In a configuration with four black pacmen, an illusory white square emerges in the center, which does not happen when the same local edges occur in a configuration with four black crosses.
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Neurophysiological Data And Model Explanations About Figure
In their classic article about the coding of border ownership in monkey visual cortex, Zhou et al. identified cells in cortical area V2 that responded selectively to the combination of a particular image contrast at a surface border in a 2D picture, as well as to the border ownership property of being at the left side or right side of the surface . For example, the same light-dark edge of a region could be on the left side of a dark square or the right side of a light square. Many V2 border ownership cells responded selectively to the combination of contrast and border position. Other cells were sensitive to one or the other property, but not both. The border ownership properties emerged less than 25 ms after response onset, and these various properties were nearly independent of surface size. How this combination of contrast-sensitivity and border ownership properties could arise in figures of this type, as well as its fast action, was explained in Section 3.
Zhou et al. also found similar properties using random dot stereogram displays. Here edges were always perceived as belonging to the nearer surface, a property that was explained and simulated using the 3D LAMINART model in simulations of random dot stereogram percepts by Fang and Grossberg .
Grouping Principles In Discrete Dynamic Patterns
Apparent motion is perceived when an object is presented in two or more successive frames at different spatial locations with proper durations and intervals. As discussed before, showed that under certain conditions it is possible to perceive pure motion, where motion is perceived without perceiving the moving object itself. The optimal timing and spacing between successively presented object presentations was investigated in more detail by , who found a direct relationship between the optimal temporal and the optimal spatial interval for perceived apparent motion. Later studies, however, have shown that the relationship between the optimal temporal and spatial interval depends on the stimuli used. For example, using horizontal arrays of dots that were displaced on successive frames, found that the spacing of the dots in the array strongly influenced the apparent motion percept in addition to the effects of the temporal interval between frames and the spatial displacement of the entire array.
and are dot lattices presented in alternation.
The affinity function. The objecthood functions.
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The Current Status Of Gestalt Psychology
Despite signs of well-deserved respect in the U.S. and in Germany , the ideas of the Gestaltists were received with ambivalence. On the one hand, they were recognized for raising central issues and provoking important debates in psychology, theoretical biology, and other fields, but on the other hand, their mode of thinking and research style did not sit comfortably in the intellectual and social climate of the postwar world, and they were confronted with vehement criticism. Two sets of explanations have been given for this outcome . The first emphasizes institutional, political, and biographical contingencies. Koffka, Köhler and Wertheimer all left for the U.S. and obtained positions where they could do excellent research but could not train PhDs. The Gestalt schools further expansion was also handicapped by the early deaths of Max Wertheimer in 1943 and Kurt Koffka in 1941, as well as many other Gestalt psychologists of the first and second generation . In Germany, Metzger, Rausch, and Gottschaldt did have a large number of PhD students, but few of them carried on in the Gestalt tradition. A notable exception is Lothar Spillmann, who obtained his D. Phil. with Metzger in Münster in 1964 and who pioneered the impact of Gestalt ideas in modern neurophysiology ever since .
Why Designers Should Care About The Gestalt Principles
Great designers understand the powerful role that psychology plays in visual perception. What happens when someones eye meets your design creations? How does their mind react to the message your piece is sharing? Laura Busche, Brand Content Strategist at Autodesk
Think about that quote for a minute. When people first see your designs, how do they experience them? To understand what makes UI design work, you need to understand the psychology of human perception.
The fundamental law that governs a Gestalt principle is that we tend to order our experience in a manner thats regular, orderly, and recognizable. This is what allows us to create meaning in a complex and chaotic world. And having a solid understanding of how these principles work will help you in three ways.
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