Good Continuation & Color 1
Abstract
Previous research has shown individuals tend to continue the lines of occluded objects to form meaningful shapes and figures, this phenomenon is known as good continuation (Goldstein, 2008). In the present study it was hypothesized that color would eliminate the effects of good continuation. In this within subjects design subjects viewed simple occluded shapes with no color present, with each shape being a different color and with all shapes in the figure one solid color. The results show individuals see one shape more often when the figure is one solid color, meaning in certain situations color can diminish the effects of good continuation.
Gestalt psychology was essentially founded by Max Wertheimer in the early 1900s and centers around the principle that the way humans perceive stimuli is not the same as the way stimuli are actually presented in the environment. The main focus of Gestalt psychology is the whole picture, people and scientists should look at an object or stimulus as a whole instead of a grouping of individual parts
(Hergenhahn, 2009). For example, a chair is an entire chair not four legs a seat and a seatback. Gestalt psychologists over the years have developed over one-hundred principles to organize perception, the more important of which include; closure, proximity, occlusion and good continuation. For instance, one of the main principles of the Gestalt psychological theoretical system are figure-ground relationships, which is the division of one’s attention on a particular object or stimulus (what is being attended to is the figure and everything around the object of attention is the ground). Gestalt principles are not distinctly used one by one through humans’ perceptions but are used in combination (Hergenhahn, 2009). Gestalt psychologists’ primary influences on the psychological community were on perception. However,

Good Continuation & Color 2
Gestaltists did develop theories and explanations for learning and memory but they are not relevant for the study at hand.
As stated earlier Gestalt psychological principles were primarily concerned with object perception and in particular how humans group and visually segment objects. Wertheimer, founder of
Gestalt psychology, also developed the concept of good continuation. A very basic definition of the principle states good continuation is an individual’s tendency to continue the lines of objects in smooth curving or straight fashions that are consistent with the line’s visible properties. This means, people try to complete or continue the lines they see in ways that seem significant to the perceiver. Good continuation may be applied to images of tightly bound knots, abstract objects and the completion of lines to form simple shapes. It is the concept of good continuation that allows us to see a figure as five grouped and complete circles instead of nine abstract shapes (see Figure 1 ) because the entire picture of the five rings is perceived instead of a broken and segmented set of shapes (Goldstein, 2007). Wertheimer originally coined the concept as ‘factor direction’ and the ‘factor of good curve’ but the term ‘good continuation’ was the label that stuck with the concept. Wertheimer gave no definitive definition of good continuation, the picture demonstrations drawn up by Wertheimer himself were to serve as definers of the principle.
Although the concept of good continuation was developed in the 1920s it is still apparent today as some researchers contend that it is good continuation which is the most practically important and useful of all the Gestalt principles in present day society (Kellman, 2000).
Figure 1 : Good continuation allows individuals to see the stimulus as five complete circles not nine separate shapes.
Some researchers have developed algorithms to predict how individuals will continue and group lines at differing angles and juxtapositions in order to prove the effects of good continuation in the human perceptual process. These researchers have found that as Wertheimer had suggested the union of lines at
180 degrees produces stronger grouping than at any other angles. These results suggest good continuation is the product of forming straight lines known as rectilinearity, a line’s orientation and if the line is enclosed or not (Prytulak, 1974). These findings validate the concept of good continuation from a separate viewpoint as the researchers were able to predict how and when good continuation would occur

Good Continuation & Color 3 through a method not suggested by the original theorists. This conclusion offers convergent validity for existence of the principle.
Vision researchers had hypothesized that individuals perceive closed contoured objects faster and more precisely than open contoured objects due to a certain neural mechanism (the reverberating neural circuit). This was measured through testing how quickly individuals perceived closed and open circles and other abstract shapes. However, the researchers found that there was no difference in the way or speed with which individuals perceived open or close contoured objects. The participants did not perceive any difference between an open figure and a closed figure; they were seeing different stimuli with their eyes but not perceiving different stimuli in their brains. This can be explained through the processes of good continuation; the participants in the study did not perceive the open shapes differently because they were continuing the lines of the stimuli to complete them and form whole shapes (Tversky,
Geisler & Perry, 2004). Although the participants were being presented different stimuli through the use of good continuation they were completing the open stimuli to form closed figures.
Wouterlood and Boselie (1992) studied the good continuation of occluded images. The study of how humans distinguish occluded objects gives insight as to how humans perceive the world. The researchers studied how individuals perceived abstract shapes which were occluded or covered up by other abstract figures; this was performed over two separate experiments. The researchers reached a few conclusions which are pertinent to the present study. One being that individuals exhibit a tendency to continue to lines of occluded objects making the least number of corners as possible. Furthermore, the researchers concluded that individuals tend to continue the lines of occluded objects to form familiar shapes and figures (Wouterlood & Boselie, 1992). The data suggest individuals will continue the lines of occluded figures to form complete familiar shapes. Even though the principles of Gestalt psychology can explain many aspects of the human perceptual process and reasons why humans may not perceive exactly what is presented to them in reality, Gestalt psychology makes almost no reference to color in perception
(Benjafield, 2008). The lack of data and discussion of color suggests that Gestalt psychology may not be able to explain color and the effects it has on perception in humans.
Wertheimer offers no mention of a possible neural mechanism that influences good continuation.
The Gestaltists believed the brain functions as a unit, everything that enters the brain is influenced by prior knowledge and everything that enters the brain influences prior knowledge (Hergenhahn, 2009).
This description of brain functioning says the brain does not have a specific structure for shape and color perception but perceives the two holistically. However, the present study is to determine color’s effects on good continuation which may have neurological underpinnings. Lee and Blake (2001) cited evidence for a neural base of good continuation data; this conclusion stated that the visual input structures into the

Good Continuation & Color 4 brain act synergistically with temporal structures to create the necessary information to perceive the continuation of lines in various figures.
If object perception and color perception have a neural basis then good continuation involving objects and color most likely has some neural basis. Object perception and object orientation is performed in various structures throughout the brain. Simple contour orientation (seeing the shape and direction of two-dimensional objects) of objects is performed in the visual ventral pathway which includes the primary visual cortex, the V4 structure and the inferotemporal cortex (IT cortex) (Connor,
2006). It has been shown that color is processed in the brain by the same neural circuits that process luminance and visual form (object shape) (Gegenfurtner, 2003). Meaning, if color and shape are processed by the same neural circuits color may have an influence on object perception and good continuation of figures. Some researchers state the ventral pathway (including the V2, V4 and IT cortex) contains perception of shape, size and color. On the other hand, proponents of the ‘segregation hypothesis’ contend that different visual attributes such as shape, size and color are processed separately between the retinogeniculate pathway and the extrastriate cortex in the visual cortex of the human brain
(Gegenfurtner, 2003). In both cases color may still have an effect on the good continuation of occluded objects.
The concept of good continuation has been established in the psychological community
(Hergenhahn, 2009; Kellman, 2000) along with evidence for the good continuation of occluded figures
(Wouterlood & Boselie, 1992). The present study is being conducted to attempt to determine the effects of color on the good continuation of occluded objects. Researchers will use simple occluded shapes as stimuli, the shapes will be either black and white outlines without color (outline condition), two different colors (two color condition) or both shapes in the occluded figure will be the same color (solid color condition). According to previous good continuation research participants should exhibit good continuation for the outlined and two-color figures and not for the solid color figures. This is evident because solid color supposedly eliminates the lines of the occluded objects whereas the presence of shapes in different colors should enhance the lines of the occluded shapes. Therefore, it is the hypothesis of the present study that participants will perceive the solid color shapes as one complete shape therefore eliminating the effects of good continuation of occluded shapes with color. Due to color superseding the effects of simple object perception, this hypothesis also endorses the segregation hypothesis of color vision.
Participants

Good Continuation & Color 5
Participants were 30 Winona State University students who volunteered to participate in a study on the perception of colored shapes. Participants received minimal compensation for their participation in the form of extra credit points in a psychology course they were currently enrolled in.
Materials
The materials for the study included an answers packet for participants along with figure cards to show participants the figures which were being presented. The answer packets were each ten pages long.
The first two pages were for the practice run which ran the same as the actual test but were not scored, the remaining eight pages were used for the actual test which was used for the data analysis. The first sheet and the third sheet contained the instructions for participants; these sheets marked the beginning of both the practice test and actual test. The instructions read, “For every figure you are shown, check in the list which shapes you see in the figure or simply check polygon, if you do not recognize a shape.” For each figure shown there was a shapes list with a small blank next to the shape name for participants to check off. In each shapes list the shapes listed were: square/rectangle, triangle, circle, hexagon, trapezoid, parallelogram, diamond, pentagon and lastly, polygon. For pages one and three in the packet, two shapes lists appeared and for the remaining sheets, four shapes lists were used. One shapes list was used for each figure shown to the participants.
The figure cards were laminated, half-sheets of papers. There were 36 cards in total, six for the practice run and 30 for the actual test. Each card contained two shapes, one shape occluding
(overlapping) the other. There were three conditions, the outline condition, the two color condition and the solid color condition. Twelve of the figure cards were presented for the outline condition (black and white shapes with no color present). Another twelve of the figure cards were presented in for the solid color condition (the same color for both shapes). The final twelve figure cards were presented for the two color condition with each shape being a different color. The shape names listed on the shapes lists matched the shapes used for the figure cards. Each shape combination was used one time in each condition but the position of the shapes on the card was changed. For instance, the combination of a square and triangle were used one time in all three conditions the triangle was presented on the right hand side of the square for the outline condition, the left hand of the square for the solid color condition and directly in the middle of the square in the two color condition (see Figure 2) . The same colors were used in the two conditions which involved the use of color. Pens were also provided to the participants to mark their answers in the packets.

Good Continuation & Color 6
Figure 2: Examples of figure cards and the positioning of each shaped combination.
Outline Condition Solid Color Condition Two Color Condition
Procedure
In this within subjects design each participant was exposed to the three conditions meaning, the conditions had to be counterbalanced to control for possible order effects. The design was counterbalanced in a Latin square format into six pairings. In the six pairings each condition appeared twice in the first, second and third position of presentation to the participants. Each of the six pairings was used five times throughout the study, to distribute the pairings evenly over the thirty subjects. The order of the figures shown in each condition was randomized before each participant was tested.
Two participants took part in the study per testing session, each session lasted about twentyminutes. The participants were seated across from the experimenter. After obtaining informed consent, the researcher introduced the participants and began the study. Participants were told they would be shown colored figures involving a few shapes, the figures may be one color, two colors or no colors at all.
They were also instructed to indicate their first impression when marking the shapes in their shapes list.
If they saw two separate shapes they were to mark those two shapes down in their answer packets.
Lastly, they were instructed to mark the shapes that they first perceived in viewing the figure, however, if they saw one multi-sided shape they should mark polygon and wait for the next figure to be shown. Once the directions were given and any questions the participants had were answered the researcher proceeded with the practice test.
The practice test consisted of six figures (two from each condition). Each figure was shown to the participants for about 2 seconds, the researcher then allowed time for participants to mark their answers before moving on to the next figure. Upon completion of the practice run the researcher reviewed the answers to ensure there were no discrepancies in how to mark one’s answers, the researcher then answered any further questions and then the full test began. The full test was run in the same manner

Good Continuation & Color 7 as the practice test, however, there were thirty figures (ten in each condition) for the full test. Each participant was subjected to all three conditions. Following the administration of the thirty-item full test, participants were debriefed and subsequently released from their duties of the research study.
A total of 30 participants were tested across all three conditions. There was no evidence of order effects between the three conditions F (1,29) = .
053, p > .
05. There were significant differences in the three conditions on the number of times participants viewed the figures as one shape F (1,29)= 29.719
, p
< .
001 (see Figure 3 ). Means represent the number of times participants perceived the figures as one shape. When viewing solid colored figures ( M = 2.1333
, SD = 1.9427) participants saw the solid colored figures as one shape significantly more than when viewing two-colored figures ( M = .
3667, SD = .
7184) and outlined figures ( M = .
3667, SD = .
61495), p < .
001. There was no significant difference between the two-colored figures and the outlines figures p > .05
. Solid colored figures were more likely to be perceived as one shape than those figures in the remaining two conditions.
Figure 3: Mean number of times participants perceived one shape compared to two for each figure shown under each condition.
4
3,5
3
2,5
2
1,5
1
0,5
0
Outlines Two Colors Solid Color

Good Continuation & Color 8
The hypothesis of the study was proven. Participants perceived the solid color figures as one shape significantly more than the outlined and two colored figures. Meaning, in certain situations color diminishes the effects of the good continuation of occluded objects. Although the effect was significant, participants did not always see the figures in the solid color condition as one shape, in fact participants perceived the solid colored figures as two shapes more often than they perceived them as one multisided polygon. This finding actually brings up more questions than it answers. Overall, it can be concluded that color can diminish the effects of the good continuation of occluded object for certain figures.
Nevertheless, the results do not offer insight as to why color diminished the effects of good continuation for certain figures and not others.
Since the same combinations of shapes were used across all conditions and each individual was exposed to all three conditions it can be assumed that the conclusion is not due to a flaw in the methodology. One reason the solid colored figures may be perceived as two shapes in some combinations and one shape in other combinations is the difficulty of the figures. Some figures were arranged in ways that it was still obvious what shapes the occluded objects were (see Figure 2 ) it is obvious there is a rectangle and triangle in the solid color condition. In other figure cards the shape combination was much more difficult to discern (the shapes were arranged in a way that it was more difficult to determine what shapes were being occluded). A single shape combination may have made the difficult cards near impossible and the easier cards more difficult but still able to be seen as two shapes by the participants. In future research on the topic the difficulty of the combinations along with participants’ responses to the more difficult cards should be recorded to determine if this effect was an artifact of the study or not.
Another possibility, although less likely is the colors themselves caused the differences in perception of the figures. Even though the same colors were used for the two conditions which used color, some colors may have made it more difficult to see the occluded objects than others. For instance, a solid black figure may have been more difficult to see as two shapes than a solid yellow figure. In upcoming studies single colors should be used for separate conditions in order to determine if there is a true difference in the actual colors used.
Due to the lack of overbearing evidence in for solid colors eliminating the effects of good continuation it is near impossible to conclude in any direction as to the neurological bases for shape perception, color perception and the use of good continuation. It is clear that there are neurophysiological roots to the good continuation of occluded objects but the present evidence does not offer support or refutation of the segregation hypothesis. Perceiving solid colored figures as one single shape proposes that color overrules good continuation and thus, confirms the segregation hypothesis. On the other hand,

Good Continuation & Color 9 perceiving a solid colored occluded figure as two shapes suggests the pathways for color and 2-D shape perception are integrated within the primary visual cortex. Perhaps the brain uses both processes, meaning, at some point in the ventral visual pathways of the brain color and object shape are separate and at another point closer to the primary visual cortex the two are integrated. Brain imaging studies during perception of these stimuli using techniques such as fMRI and PET scans are necessary to determine the true neurological roots of good continuation.
There were a few issues with the design which could have been changed to draw a clearer picture of the actual effect. As mentioned earlier, the difficulty of the figure cards did vary, although, which figure combinations were perceived as one shape and which combinations were perceived as two shapes was not noted. Had this data been taken into account the possible effect of the difficulty of the shape combinations would have been analyzable. Moreover, the effect of color was not taken down in the data.
Certain colors may have primed participants to view the solid figure cards as one shape or two shapes.
Since this data was not recorded it is impossible to know if the colors themselves had an effect on participants’ perceptions or not.
Based on the findings from the present study and previous research on the topic of good continuation it is apparent that further investigations are necessary to fully understand the effects of color on the good continuation of occluded objects. This study raised the questions towards the perceptual difficulty of the stimuli and the colors that were used to in the experiment. This investigation confirms that color has a significant negative effect on good continuation. More research is necessary to validate the true role of color in the Gestalt psychological principle of good continuation.
Benjafield, J. G. (2008). Revisiting Wittgenstein on Kohler and Gestalt psychology. History of the
Behavioral Sciences, 44, 99-118. Retrieved March 25, 2009, from PsychInfo database.
Connor, C. (2006). The neural space of visual shape perception. In L. Albertazzi (Eds.), Visual Thought
(pp. 105-114). Amsterdam, Netherlands: John Benjamins.
Gegenfurtner, K. R. (2003). Cortical mechanisms of colour vision. Neuroscience, 4, 563-571. Retrieved
March 25, 2009, from PsychInfo database.
Goldstein, E. B. (2007). Sensation and Perception (7 th ed.). Pittsburg, PA: Thomson Wadsworth
Hergenhahn, B. R. (2009). An Introduction to the History of Psychology (6 th ed.). United States:
Wadsworth Cengage Learning.
Kellman, P. J. (2000). An update on Gestalt Psychology. In B. Landau, J. Sabini, J. Jonides, E. L.
Newport (Eds.), Perception, Cognition and Language: Essays in Honor of Henry and Lila Gelitman
(pp. 157-190). Cambridge, MA: MIT Press.
Prytulak, L. S. (1974). Good continuation revisited. Experimental Psychology, 5, 773-777.
Wouterlood, D. & Boselie, F. (1992). A good-continuation model of some occlusion phenomena.
Psychological Research, 54, 267-277.