Visual Patterns: Neuroscience Implications

TakeAway

When we look around we often see patterns—in upholstery, wall coverings, and elsewhere.  The effects of visual patterns on how we think and behave have been thoroughly investigated by neuroscientists.  

For information on the repercussions of viewing particular colors, read this article.  Coordinating color selections is important and a significant effect on user wellbeing and performance.

Fundamental Considerations

Researchers have learned a lot about how symmetry, complexity, line, harmony, balance and other design fundamentals influence human thoughts and behaviors as well as how to best use these design elements in practice, for example, in patterns.

In 1941, Campbell reported that design with visual balance, rhythm, harmony, etc., was judged more positively than design without these attributes (Campbell, 1941).  Subsequent research has confirmed these conclusions.

More than a few years later, in an introduction to neuroaesthetics, Lehrer (2009) reviewed many of the principles of great art, which are also applicable to noteworthy design: “Balance: successful art makes use of its entire representational space, and spreads its information across the entire canvas . . . symmetry: symmetrical things, from human faces to Roman arches, are more attractive than asymmetrical ones; repetition, rhythm, orderliness: beauty is inseparable from the appearance of order. Consider the garden paintings of Monet. Pictures filled with patterns, be it subtle color repetitions or formal rhythms, appear more elegant and composed.”

Symmetry

Visual symmetry, has several forms, reflectional and rotational, for example.  It has repeatedly been linked to positive experiences.  

• Du Sautoy explores the importance of symmetry in biology, chemistry, physics, art, music, and architecture (2008). His work indicates that “The human mind is constantly drawn to anything that embodies some aspect of symmetry. Our brain seems programmed to notice and search for order and structure.”
• Brielmann and Pelli reviewed research in empirical aesthetics, neuroaesthetics and related fields (2018).  They report that “The most frequently mentioned aesthetic preference may be that for symmetry over asymmetry.”
• Symmetric patterns are preferred to asymmetric ones (Gartus, Plasser, and Leder, 2016).   
• As Lindell and Mueller detail (2011), “The more symmetrical the stimulus, the more beautiful it is deemed.”  Symmetrical patterns are, therefore, not surprisingly, viewed as more aesthetically pleasing than nonsymmetrical patterns.
• More on preferences for symmetry: “symmetrical patterns are not only used most frequently in real life, but are also produced spontaneously in the lab and are rated significantly more attractive than random patterns” (Westphal-Fitch and Fitch, 2016).  
• Friedenberg set out to learn more about our preferences for various sorts of symmetry (2018).  By manipulating images of polygons he found that “Beauty ratings . . . [were] highest for reflective symmetry, second best for rotational symmetry, and lowest for translation.” Some crucial definitions: “There are several types of symmetries.  Translational symmetry is probably the simplest, as it involves the duplication of a shape.  In reflective symmetry one half of a shape becomes the mirror image of the other.  In rotational symmetries a shape is rotated by a given degree.”  
• Weichselbaum, Leder, and Ansorge researched humans’ responses to symmetry (2018).  They share that “In perception, humans typically prefer symmetrical over asymmetrical patterns. . . . we tested the generality of the symmetry preference for different levels of individual art expertise. The preference for symmetrical versus asymmetrical abstract patterns was measured implicitly [indirectly], by an Implicit Association Test (IAT), and explicitly [directly], by a rating scale asking participants to evaluate pattern beauty. . . . In the IAT, art expertise did not alter the preference for symmetrical over asymmetrical patterns. In contrast, the explicit rating scale showed that with higher art expertise, the ratings for the beauty of asymmetrical patterns significantly increased, but, again, participants preferred symmetrical over asymmetrical patterns. . . . Evolutionary adaptation might play a role in symmetry preferences for art experts similarly to nonexperts, but experts tend to emphasize the beauty of asymmetrical depictions, eventually considering different criteria, when asked explicitly to indicate their preferences.”  So, it seems that both people who are art experts and those who are not have inherently positive responses to symmetrical patterns, but people with more art expertise, when asked directly about patterns, were more likely to respond positively to asymmetrical options.
• Leder and team’s research provides nuanced insights into human beings’ responses to symmetry (2019). The investigators learned that when they had people with an expertise related to art (artists and art historians) and people without a background in art view mandala-like designs that were symmetrical or not, and simple or complex that “non-art experts evaluated the symmetrical–complex stimuli as most beautiful, followed in descending order by symmetrical–simple, asymmetrical–complex, and asymmetrical–simple stimuli. This was an expected pattern of responses that has been previously shown to be largely stable that is for non-art expert participants. What was surprising, however, was that both groups of experts showed a contrasting, even reversed, pattern of responses: Unlike the non-art experts who found symmetrical and complex stimuli to be most beautiful, the art experts found asymmetrical and simple stimuli to be most beautiful.”  
• Symmetry generally has a stronger influence on liking for something viewed than complexity (complexity is discussed in a few paragraphs; Gartus and Leder, 2013).
• Existing research preferences for symmetry is neatly summarized by Leder and Tinio (2014): “Symmetry is found in nature, symbol systems, and graphic depictions across different cultures and eras.  Even infants show preference for symmetry. . . . positive bias toward symmetry has been found using different stimuli. . . . the preference for stimuli has also been shown in aesthetic judgment of meaningless, abstract patterns.”  For information on the many desirable implications of having preferred sorts of experience, read Some of Our Favorite (and Not So Favorite) Things.  
• Comments by Makin, Pecchinenda, and Bertamini (2012) support those of Leder and Tinio (2014): “Symmetry and beauty are strongly linked. . . . a reflected pattern was preferred to a rotation” and both were more positively evaluated than random patterns.  Symmetry is different from balance; “Artists may find balance intuitively by offsetting figural elements with equal subjective visual weight. . . . balance can be quantified and used as a predictor of preference ratings [more balance, higher preference].”
• Luffarelli and colleagues researched associations to symmetrical and asymmetrical logos (2015).  The Luffarelli team found that “visual asymmetry is associated with excitement in memory. . . . the combination of a symmetrical (asymmetrical) logo with an exciting brand personality harms (boosts) customer-based, company-based, and financial-based equity.” So while asymmetric logos are not as positively received as symmetrical ones, they are associated in viewers’ minds with higher energy levels.
• Bajaj and Bond also investigated links between design elements and brand-related opinions (2018). They share that “asymmetry in brand elements evokes arousal [excitement] in observers, which spills over to impressions of the brand itself. . . . symmetry was negatively associated with perceptions of brand excitement. . . . Among the . . . academic research . . .  a common finding has been the broad benefits of symmetry for perceptions of beauty, perfection, etc. . . . our findings suggest that for brands whose positioning relies on excitement, the direct, positive effect of symmetry through esthetic pleasure may be offset by its indirect, negative effect through inferences regarding brand personality. . . . results suggested a strong association between visual symmetry and brand sophistication; indeed, luxury brands often adopt a classical style characterized by calmness, order, and idealism, in which symmetry is a fundamental characteristic. . . . symmetry represents harmony . . . and stability.” Bajaj and Bond’s work focused on mirror symmetry. 
• Stamatogiannakis and team (2016) report that “our results indicate that compared to symmetrical logos, asymmetrical logos are associated in memory with notions related to excitement. . . . Conversely, compared to asymmetrical logos, symmetrical logos are associated with notions related to sincerity, competence, and ruggedness.” The group goes on to state that “asymmetrical logos lead to higher brand equity for brands with exciting brand personalities, and to lower brand equity for those with less exciting brand personalities. . . . The visual design of products, packages, and logos should be consistent with other brand elements to augment brand equity, even if this implies going against principles of good design.” Brand equity was defined as “tangible and intangible value.”
• Studies have specifically addressed links between symmetry and mood.  Pecchinenda and colleagues found that not only is visual symmetry preferred in multiple contexts including “the aesthetic appreciation of works of art,” it also induces “positive affect [mood] and subjective beauty” (Pecchinenda, Bertamini, Makin, and Ruta, 2014). The research team observed, for example that “symmetric dot-patterns spontaneously elicit positive affect. . . . visual symmetry in novel, abstract patterns spontaneously engenders positive affect, which . . .  does not rely on attention being focused on symmetry.”  The cognitive and behavioral implications of positive moods are discussed here.  

For more information on symmetry, read this article. 

Visual Complexity/Orderliness

Visual complexity is an important driver of experience; individual visual patterns can be more or less complex and the use of surface patterns contributes to the visual complexity of an environment.  Both too much and too little are bad for our mood and cognitive performance.  Cognitive science research reveals how the amount of information we pick up from the world around us influences our mental and physical wellbeing, how to determine how visually complex our world is, and instances in which we must be particularly careful to guard against excessive visual complexity, disorder, and clutter.

By surveying a range of different scenes and items viewed, Nadal, Munar, Marty, and Cela-Conde learned that visual complexity is determined by the number of different elements present, and their organization and symmetry (2010). Scenes with more colors and clutter are generally seen as more complex and more open scenes tend to be categorized as less complex (Oliva, Mack, Shrestha, and Peeper, 2004). As Chaparro and Chaparro report, color can be used to reduce visual clutter when multiple items are the same shade, particularly if those “same-colored” elements are next to each other (2017).

Visual complexity can be measured by experts using sophisticated computer programs and complicated mathematical algorithms.  The most practical way to assess visual complexity, without computers and calculators, is to compare an existing or potential space to one with known visual complexity.   

The interiors of homes designed by Frank Lloyd Wright generally have moderate visual complexity.  Describing Frank Lloyd Wright interiors as having moderate visual complexity is supported by calculations included in Vaughan and Ostwald (2014). This link will bring you to images of the Willson Hospice House, where moderate levels of visual complexity are also seen in the common interior spaces. Additional examples:  the Japanese flag has low visual complexity while the United States flag is very visually complex; the Canadian flag has moderate visual complexity.

There are clear advantages to viewing scenes/patterns with moderate visual complexity.   

• Moderate visual complexity is preferred, in general (Berlyne, 1971).  Also, people would rather look at scenes/artwork/patterns that are moderately complex (Forsythe, Nadal, Sheehy, Cela-Conde and Sawey, 2011). For information on the many desirable implications of having preferred sorts of experience, read Some of Our Favorite (and Not So Favorite) Things. Seeing favored forms can boost mood, support better problem solving and creative thinking, and smooth our interactions with others, just for starters.
• Krentz and Earl learned that infants and adults prefer the same sorts of abstract art – images with high visual contrast and moderate visual complexity (2013).  They conclude that “although we cannot make the claim that these preferences are innate, we can suggest that their emergence in the first 6 months of life are both biologically based and driven by exposure to highly reliable sources of visual information from the environment.”
• More complex (than medium) patterns increase the energy levels of viewers (Mahnke, 1996).  Higher energy levels may be desired in particular situations, for example, in exercise areas or amusement parks, and more visual complexity should be used accordingly, as needed.
• Symmetry generally reduces the amount of perceived complexity (Leder and Tinio, 2014).  Chen, Wu, and Wu (2011) learned that “Symmetric patterns are more appealing to human observers than asymmetric ones. . . . [and] preference can be accounted for by the complexity of the image.”  
• Visual complexity influences the apparent size of objects; items seen against complex backdrops seem smaller than those seen against simpler ones (Ketron, 2018).  Ketron (2018) found that “high visual complexity decreases consumer size perceptions of a focal product . . . high complexity pulls consumer attention away from the focal product. This . . . leads consumers to perceptually minimize size to avoid information overload . . . when larger perceived sizes are more desirable for a product category, a reduction in the visual complexity surrounding the product would be more desirable. . . . when perceived sizes may benefit from a decrease (i.e., apparel), enhancing the visual complexity surrounding the product can help to achieve this effect. . . . decorated mirrors or visually complex reflections in those mirrors could lead to smaller body size perceptions and boosted self-esteem.” 

For more information on visual complexity, read this article.  

Lines and Shapes

Humans have clear reactions to particular lines and shapes, and both lines and shapes can appear in visual patterns. 

Lines can go up or down, or not:  

• Horizontal and vertical lines are more positively received than diagonal ones because they are easier for our visual system to process (Lindell and Mueller, 2011).
• Upward diagonals, those lower on the left and raising to the upper right, are associated with higher activity levels than descending diagonals, those that are higher to the left and lower to the right, which are linked in viewers’ minds to lower activity levels (Schlosser and Rikhi, 2012).  Descending diagonals are associated with relaxation. 

Design elements can be more curvilinear or rectilinear:   

• Brielmann and Pelli (2018) report that “Perhaps the most broadly established aesthetic preference is the one of curvature over angularity.  People like the appearance of otherwise equivalent shapes and objects more if their contours are round rather than sharp and angular, and this is the case in various cultures across the globe.”
• Objects and patterns with curved features are definitely preferred to those with pointed elements and sharp angles (Bar and Neta, 2006). 
• Stanischewski and teammates (2020) review and extend research related to human responses to curvilinearity and rectillinearity.  They share that previous research has shown that “Curvilinearity is a perceptual feature that robustly predicts preference ratings for a variety of visual stimuli. . . . The present results support the idea that people prefer curved stimuli over angular ones overall. Specifically, participants rated curved stimuli as more pleasing and harmonious than the angular stimuli.”
• Palumbo and Bertamini’s research verifies that smooth curved contours are preferred to angular ones (2016).  They share that via their project “Preference for smooth curvature was confirmed using irregular abstract shapes.” The scientists report that “In empirical aesthetics, the preference for smooth curvature is a phenomenon which has been confirmed with a variety of visual stimuli from abstract meaningless shapes or patterns . . . to more articulated displays such as pictures or drawings of interior design spaces . . . or even familiar objects. . . .  In all three experiments, we found that curved shapes were preferred. This confirmed previous reports.”
• Salgado-Montejo and colleagues probed psychological responses to concave and convex lines (2015).  They learned via data collected in the United Kingdom and Colombia that when “participants viewed four variants (concave [smile-like] line, convex [frown-like] line, straight line, line absent) of three different products (tea, shampoo, juice). . . . [that there was] a general tendency across scales, products, and countries for the participants to rate products more positively and to choose products more frequently when they displayed a concave line relative to a convex line . . . the effects were present for both concave and convex lines, but were stronger in the concave instance.”   
• Watson and colleagues researched our emotional responses to particular shapes (2012).  As they report, "Previous work has shown that some simple visual forms—such as angular lines, acute angles, and V-shapes—are perceived as conveying negative valence."  Negative valence is a psychological term that is used to describe negative emotions.  Elements with negative valence can produce stress.  In a sophisticated study, Watson, Blagrove, Evans, and Moore learned that "a downward pointing triangle conveys negative valence." 
• Work by Larson and colleagues indicates that V shapes draw our attention before other shapes when multiple shapes are arranged randomly in a field and that once our eyes find V shapes, they tend to linger on them  (Larson, Aronoff, and Stearns, 2007). Previous research has shown that “angular v-shaped images (similar to the angles in the eyebrows, cheeks, chin, and jaw in angry expressions) and rounded images (similar to the curves found in the cheeks, eyes, and mouth in happy expressions) conveyed an angry and happy meaning respectively” and that v-shaped images in schematic faces are seen as negative and threatening. 
• Ghoshal and team (2016) report that “Our results suggest that for products where perceived functionality is more critical than perceived hedonics [pleasantness, pleasurableness], it may be advantageous for product contours to be designed angular rather than curved.  Conversely, for products where hedonic perceptions are more critical, contours of the product should be curved or rounded, rather than angular.”  So, functionality is linked to more angular designs and pleasure to more curved ones.
• Blazhenkova and Kumar studied people’s associations to different shapes (2018). They found that participants in their study “associated curved shapes with sweet taste, quiet or calm sound, vanilla smell, green color, smooth texture, relieved emotion, female gender. . . . In contrast, they associated angular shapes with sour taste, loud or dynamic sound, spicy or citrus smell, red color, rough texture, excited or surprise emotion, male gender.”   
• Turoman and team confirm previously established links between shapes and tastes (2018).  They verified that “round shapes are associated with sweet taste, whereas angular shapes are associated with sour and bitter tastes. . . . A significant relationship was observed between the taste and appraisal scores of the shapes, suggesting that the affective [emotional] factors of pleasantness and threat underlie the shape-taste correspondence.  These results were consistent across cultures, when we compared participants from Taiwanese and Western (UK, US, Canada) cultures.”
• Liu, Bogicevic, and Mattila (“Curves or Angles?  Shapes in Businesses Affect Customer Response, 2018) found that: “When you’re waiting in a busy restaurant or doctor’s office, it may matter whether the tables, light fixtures and other objects are round or square. In a laboratory study, researchers found the shape of physical objects in a service business affected customer satisfaction, depending on how crowded the business was in the experimental scenarios. Angular shapes suggested competence to customers, which increased their level of satisfaction when the business was busy. In contrast, circles suggested friendliness and warmth to customers, which increased their satisfaction when the business was not crowded.” The study-related press release goes on to report that “Circles are a signal of warmth due to their resemblance to the sun, and suggest harmony and friendliness. Hard angles are generally found in human-made objects – think street grids in cities – and so have an association with competence, toughness and strength.”  Participants in the studies conducted were asked to imagine themselves in a restaurant or a health care facility where either curvy or rectilinear design elements were more prevalent.  For example, “Half the people were shown pictures . . . in which the restaurant logo, ceiling lights, a flower vase, candles, wall paintings and tables all had rounded shapes. The other half saw the same objects, but they all had straight lines and sharp corners.” Liu, Bogicevic, and Mattila (2018) effectively summarize their conclusions: “The findings suggest that in busy settings, angular shape cues increase customer satisfaction through perceived competence of the service provider. Conversely, in non-busy settings, circular shape cues enhance customer satisfaction via warmth perceptions.”
• People who see themselves as generally independent from other humans think that angular shapes are slightly more attractive, and people who perceive themselves as primarily interdependent with others find rounded shapes a little more attractive (Zhang, Feick, and Price, 2006). People are more apt to see themselves as interdependent with others in collectivist cultures and to view themselves as independent in individualistic cultures.  This means different patternsare most appropriate for particular cultures.  For information on whether a culture is collectivist or individualistic, see charts published in Cultures and Organizations by Hofstede, Hofstede, and Minkov (2010) and discussed here.  The Zhang, Feick, and Price research builds on previous work that found “angular shapes tend to induce associations with traits that express energy, toughness, and strength. In contrast, rounded shapes tend to induce associations with traits that express approachableness, friendliness, and harmony” (Zhang, Feick, and Price, 2006).
• Friedenberg and Bertamini learned that some polygons are preferred to others (2015).  More specifically: “observers rated the attractiveness of octagonal polygons that varied in contour length [length of line segments outlining them] but had approximate constant area. Thus, the shapes differed in compactness. Shapes with partial symmetry were judged to be more attractive as were those with greater total contour length. In a second experiment, participants judged polygons with different numbers of concavities [inward bends] but with constant contour length. Shapes with more concavities were considered more attractive.”  This finding may be useful in the selection of wallpapers and upholstery fabrics, for example.
• McManus and Wu (2013) learned that although people vary in their preferences for various rectangles, the meanings associated with various rectangles are consistent cross-culturally (study participants were from the United Kingdom and China): “Squares. . . . are [perceived to be] strong, hard, masculine, balanced, still, bulky, contented, solid, stable, and awkward . . . . wide, flat, horizontal rectangles were seen as passive, balanced, bulky, contented, solid, stable, awkward, and relaxed, whereas tall, thin, vertical rectangles were the converse, being active, unbalanced, compact, discontented, fluid, unstable, elegant, and tense. . . . Although stupid was not a word used to differentiate between the rectangles, it was particularly applied to the random polygons, which were seen as more stupid than the rectangles, whereas triangles and ellipses were more clever than the rectangles.”
• McCarthy found that squares are linked to ruggedness and circles to sophistication (2012).
• Both blind and sighted people have similar associations to circles and squares, indicating strong consistencies in the interpretations of these abstract shapes. Kennedy (2006), recapping research he conducted several years ago with Liu, reports the following associations to circles and squares (circle association noted first, square association second): soft-hard (100%); mother-father (94%); happy-sad (94%); good-evil (89%); love-hate (89%); alive-dead (87%); bright-dark (87%); light-heavy (85%); warm-cold (81%); summer-winter (81%); weak-strong (79%); fast-slow (79%); cat-dog (74%); and Spring-Fall (74%), for example. These data mean, for example, that 94% of participants in the study linked happy with a circle and sad with a square and 79% linked fast to a circle and slow to a square. Participants were asked to indicate the word in each pair that best related to a circle and the one that best related to a square. Percentages quoted are for sighted subjects and choices by blind volunteers were “similar.” 

Harmony, Balance, and Rhythm

Kumar carefully evaluated classic aesthetic concepts including harmony and balance (2016).  Reporting on his findings, Kumar states, “humans are sensitive to balance in visual compositions. . . . imbalance for the sale of imbalance tends to be unappealing. . . . consumers generally prefer harmony to disharmony, even in a composition with a variety of elements.” Harmony increases perceived attractiveness.  

As noted earlier, in an Introduction to neuroaesthetics, Lehrer (2009) reviewed principles of great art, his insights are also applicable to design generally: “repetition, rhythm, orderliness: beauty is inseparable from the appearance of order.”

Pattern-Specific Research

Fractal Patterns 

Visual fractals have an important influence on user experience. 

• In all fractals, the components of a pattern appear at various magnifications within the same overall unit. For example, the smallest visible components of ferns have the same basic form as entire fern leaves. Prairie grasses clouds, tree lines, and winding streams are also naturally fractal.  Seeing fractals influences our psychological state (for images of fractals, visit http://en.wikipedia.org/wiki/Fractals) (Wise, 2002).
• Natural fractal patterns in man-made designs share the same mathematical formulae as fractal images found in nature—although they may not look like anything actually found in nature and the best way for a layperson to know if a particular design is a natural fractal is if the manufacturer of a product has identified it as a natural fractal pattern.
• Natural fractals have been used intuitively by some of this century’s most well-respected architects and artists, such as Frank Lloyd Wright, Richard Neutra, and Jackson Pollock. 
• Across several studies, humans seem to prefer the moderate complexity of fractal values of 1.3 to 1.5, and judge them more aesthetically pleasing (Joye, 2007).  These are the sorts of fractals found in nature. 
• Wise and Hazzard (2002) share that fractals with these parameters are relaxing to view and produce the sorts of backgrounds against which primitive humans could have easily spotted approaching danger, such as lions or tigers or bears. they are also good choices for workplace wall coverings, etc., patterns now, for example.  
• Wise (2002) reports that when people see or hear fractal patterns like those found in nature, they are more relaxed and devote less mental energy to monitoring their environment. People experiencing natural fractals thus have more mental processing power available for valued activities such as being creative, monitoring details, and interacting with others. Wise goes on to share that the experience of natural fractals has been shown to speed recovery from surgery and to increase office worker productivity. Research in knowledge-worker offices has shown that the use of natural fractals in an environment can improve memory while reducing stress and keeping cognitive performance from deteriorating over time. 
• Taylor and Spehar (2016) report that seeing moderately complex fractals, the sorts found in natural environments, reduces stress: “Humans are continually exposed to the rich visual complexity generated by the repetition of fractal patterns at different size scales. Fractals are prevalent in natural scenery [for example]. . . . we . . . investigate the powerful significance of fractals for the human visual system. In particular, we propose that fractals with midrange complexity (D = 1.3–1.5 measured on a scale between D = 1.1 for low complexity and D = 1.9 for high complexity) play a unique role in our visual experiences because the visual system has adapted to these prevalent natural patterns. . . . the visual system processes mid-D fractals with relative ease. This fluency optimizes the observer’s capabilities (such as enhanced attention and pattern recognition) and generates an aesthetic experience accompanied by a reduction in the observer’s physiological stress levels.”  
• Abboushi and colleagues (2019) report that “The visual patterns of fractal stimuli on a computer screen and the brightness patterns of light projected onto room surfaces have independently been shown to influence human perceptual responses. . . . This paper reports on . . . [responses] elicited by varying complexities of fractal light patterns projected on walls and floors of an interior space.  The results suggest that fractal light patterns of medium to medium-high complexity (quantified by the fractal dimension D = 1.5 – 1.7) were significantly more visually interesting than other patterns. . . . the use of medium to medium-high complexity fractal light patterns in interior spaces may be useful for enhancing occupants’ visual interest and mood. . . . These results suggest that viewing fractal light patterns in interior spaces may elicit restorative and biophilic benefits similar to those of nature scenes.” Fractal patterns are plentiful in the natural world and are found in clouds and tree forms, for example. 
• Brielmann and colleagues (2022) evaluate how the presence of visual fractals influences our experiences in cities; they present an impassioned case for the use of fractals. The Brielmann-lead team reports that “use of multiple fractals needs to reintegrate with biophilic and traditional architecture in urban design for their proven positive effects on health and well-being. Such benefits include striking reductions in observers’ stress and mental fatigue. . . . We see the complex multiple fractal design techniques applied in traditional artifacts, ornamentation, and art. . . . The salutogenic effect of multiple fractal environments can contribute to recovery from physical or mental illness or injury. Conversely, the lack of fractal aesthetics in unnatural environments puts a strain on the visual system, inducing negative responses such as headaches. . . . modernist design is not as satisfying as traditional and classical design.”
• Joye, Steg, Unal, and Pals completed research confirming the positive psychological benefits of viewing natural fractals (2016).  As they report “we investigated whether visual complexity deriving from internally repeating visual information over many scale levels [in other words fractals] is a source of perceptual fluency. . . . our findings confirm that complexity deriving from internal repetition of visual information can be easy on the mind [easy to process cognitively]. . . . our results are consistent with, and further support the view that fractal characteristics could be one of the crucial (visual) drivers of restorative responses and other positive psychological responses to nature.”
• Researchers have determined that children as young as 3 respond positively to seeing fractal patterns, just as adults do (“Study Finds That by Age 3 Kids Prefer Nature’s Fractal Patterns,” 2020).  Robles, Taylor, Sereno, Liaw, and Baldwin found that “Before their third birthdays, children already have an adult-like preference for visual fractal patterns commonly seen in nature. . . . We found that people [both adults and children] prefer the most common natural pattern, the statistical fractal patterns of low-moderate complexity . . . ’ Robles said. . . .  The aesthetic experience of viewing nature’s fractals holds huge potential benefits, ranging from stress-reduction to refreshing mental fatigue, said co-author Richard Taylor. . . . . [Taylor also states:] ‘This study shows that incorporating fractals into urban environments can begin providing benefits from a very early age.’. . . . [Taylor] and co-author Margaret Sereno . . . also have published on the positive aesthetic benefits of installing fractal solar panels and window blinds.”  The study by Robles team is published by Nature:  Humanities and Social Sciences Communication.
• Terrapin Bright Green is making available, at their website, a useful resource for designers interested in incorporating fractals into their projects (Trombin, 2020).  Terrapin describes the available report on the website from which it can be downloaded, which is shared, below: “Fractal patterns are an intricate ubiquitous machinery behind nature’s order. . . . The unique trademark of nature to make complexity comprehensible is underpinned by fractal patterns, which apply to virtually any domain of life; to the design of built environment, fractal patterns may present opportunities to positively impact human perception, health, cognitive performance, emotions and stress.  Yet, designing with fractals can also come with implementation challenges.  This paper provides a high-level conceptual framework for thinking about design with fractals, and for promoting restorative and satisfactory environments, with a focus on the indoor environmental quality. This paper includes primary scientific research on fractals, perception and health, metrics and terminology used to describe fractals, and perspectives on design, technology and other factors than (sic) may influence the creation of fractal patterns for design projects.” The Trombin report shares information on design tools/software that can support designing with fractals. 

Golden Ratio

Support for the golden ratio is mixed.   

• The presence of the golden ratio produces a distinctive pattern of brain waves in human beings. Since antiquity, the golden ratio (1:0.618) has been considered the ideal relative proportion. Di Dio and colleagues (2007) have determined that when viewers perceive this ratio it triggers “a specific neural pattern underlying the sense of beauty in the observer.”
• Research analyzing human fondness for rectangles of various shapes indicates the golden section may not reign supreme, at least regarding preferred rectangles.  The golden section, also known as the golden ratio, relates, in the case of rectangles, to the lengths of each set of parallel sides.  McManus and colleagues (2010) found that participants in their study had highly consistent individual preferences for particular rectangle shapes.  Overall their results “provide little or no support for the special status of the Golden Section.  Few participants showed preferences that could be said to be at the Golden Section. . . . It appears to be time, therefore, for any special status of the Golden Section in rectangle aesthetics to be dropped.”  Information was also collected about the people who participated in this study and “none of the individual difference measures, either in personality, interest in aesthetics, or in response to the experiment, explain those rectangle preference differences.”
• Stieger and Swami also gathered evidence indicating that the Golden Ratio may not be so golden after all (2015).  They “examined whether the golden ratio reflects an automatically elicited preference.” The researchers had people rate real art images and those evaluations “did not reveal a clear preference for the golden ratio over other ratios. A possible preference for the golden ratio does not seem to be automatically elicited and may, rather, be driven by art expertise. This again calls into dispute the universality of a preference for the golden ratio.”   

Additional Research with Visual Patterns  

• Friedenberg (in press) probed what makes patterns beautiful to humans. Study participants viewed straight line segments, all the same length, arranged in particular patterns. Friedenberg reports that “participants were asked to rate the perceived beauty of square texture arrays made up of oriented line segments. . . . these patterns consisted of vertical, horizontal (cardinal), and diagonally (±45°) oriented line segments. . . . Patterns with greater collinearity and fewer orientations were preferred.  Oblique orientations were generally liked more than cardinal orientations with the exception of vertical and horizontal in combination. . . . conditions that contained a mixture of cardinals and obliques were rated the lowest.”  Collinearity was defined: line segments that were next to each other with the same orientation were seen as collinear and adjacent meant “next to,” for example “above, below, to the left or right, or at one of the diagonal ‘corner’ positions in the array.” Also, “Oblique orientations refer to lines that are slanting, sloping, or diagonal, that is, to those that have an orientation other than cardinal.”  Vertical and horizontal orientations are cardinal.  When considering how his results might be applied, Friedenberg states that, for example, “decorative friezes or patterns on buildings might be more appealing if their component lines flowed in parallel with major structural components.”      
• Rodemann learned that “The larger the scale of the design, the smaller the group of people the pattern appeals to” (1999). 
• Patterns on walls that are smaller in scale tend to increase the apparent size of a space (Mahnke, 1996.)
• Seeing wood grain is a stress-reducing experience (Fell, 2010).  Fell found that “wood provides stress-reducing effects similar to the well studied effect of exposure to nature in the field of environmental psychology.”  This leads to the conclusion that “wood may be able to be applied indoors to provide stress reduction as a part of the evidence-based and biophilic design of hospitals, offices, schools, and other built environments.”  This is important because wood can be used in any sort of space—for example ones without views of nature or ones that cannot support plants.  The wood included in the test environment was birch veneer office furniture with a clear finish.
• Wilkens and team (2018) determined that some patterns, in particular some striped ones, are more likely to lead to visual stress than others.  The researchers “focus on a phenomenon known as ‘visual stress’ induced by repetitive, geometric patterns around us. Geometric patterns, particularly patterns of stripes, can be uncomfortable to look at (Wilkins et al., 1984). . . . we do not want to imply that stripes should be avoided at all costs. Using stripes to accentuate areas of danger might be highly beneficial. . . . The negative impact of such patterns on the visual system can be reduced by using thin grouting that contrasts little with the surround (thereby reducing the energy in the pattern), or by breaking the pattern up through mixing of different-sized tiles or bricks.. . . stripes that close- up are widely spaced and thus do not induce discomfort can do so when looked at from further away. . . . Avoid repetitive elements that are as wide as the space between them, because evenly-spaced stripes are the most aversive.” Additional tips on designing to minimize visual stress are available in the article by Wilkins and colleagues, which can be downloaded without charge at https://www1.essex.ac.uk/psychology/overlays/2018-246.pdf
• A research team lead by Dillon (2019) has determined that our brain may be particularly attuned to identifying lines that are parallel or perpendicular; which suggests that deviations from parallel and perpendicular conditions are reliably noted.  The researchers found that “participants were most precise when detecting 2 parallel or perpendicular lines among other pairs of lines at different relative orientations. Detection was also enhanced for 2 connected lines whose angle approached 90°, with precision peaking at 90°. These patterns emerged despite large variations in the scales and orientations of the angle exemplars. . . . the enhanced detection of perpendiculars persisted when stimuli were rotated in depth, indicating a capacity to discriminate shapes based on perpendicularity in 3 dimensions despite large variation in angles’ 2-dimensional projections. The results suggest that 2 categorical concepts which lie at the foundation of Euclidean geometry, parallelism and perpendicularity, are reflected in our discrimination of simple visual forms.”
• Only a few designers actually develop camouflage, but learning more about camouflage generally has the potential to be handy in a number of situations/settings.  Smart, Cuthill and Scott-Samuel (“Animals Should Use Short, Fast Movements to Avoid Being Located,” 2020) report in a study (done with human participants) published in the Proceedings of the Royal Society B that “movement doesn't always break camouflage and if an animal needs to move, animals that are unpatterned and use short, fast movements are less likely to be located by predators. . . . Ioan Smart . . .  lead author, said: ‘Our research has shown. . . . Localisation can be reduced, if the moving target is unpatterned, has the mean brightness of the background, it does not use a startle display before moving, and uses short, fast movements.’” Study participants were “tasked with localising upon a target displayed on peripherally viewed computer screens.”
• Hall and team (2016) report that “Static high contrast (‘dazzle’) patterns, such as zigzags, have been shown to reduce the perceived speed of an object. . . . Dynamic stripe patterns moving in the same direction as the target are found to increase the perceived speed of that target, whilst dynamic stripes moving in the opposite direction to the target reduce the perceived speed.”
• Su, Wen, and Jiang investigated how feeling excluded socially influences people’s preferences for visual density (2019).  They conducted seven separate studies and conclude that “consumers who perceive themselves as socially excluded evaluate products with dense visual patterns more positively than their non-excluded peers. . . .  This effect is attenuated [weakened] when consumers physically fill something [for instance, a water bottle] or experience a feeling of ‘temporal density’ (i.e., imagining a busy schedule with many tasks packed into a short time).” Visual density is different from visual complexity (which is discussed here): “Visual density is defined as the number of distinguishable elements in a unit area of a visual design (Donderi 2006), while visual complexity is the visual perception that can result from various factors, including details in visual features, irregularity, asymmetry, or variation in design elements and composition (Pieters et al. 2010).” A printed fabric with more polka dots per square inch is more visually dense than one with fewer polka dots in the same area, for instance. Another important definition:  “social exclusion—a state of being deprived of social relationships (Williams 2007).” If someone feels rejected or ignored, they are feeling socially excluded, for example. In the course of the experiments run, study participants were first asked to remember a time when they felt socially ignored or isolated or rejected, or they were actually excluded while playing an electronic game, for example.  Next, participants were asked to help design a telephone case or evaluate clothing or curtains, for instance. The research team suggests that, “packaging can be developed with dense patterns or designs for products that target consumers who are more likely to experience loneliness, such as senior citizens and new immigrants.”
• Dickson and teammates (2021) probed the implications of stepping on surfaces that look like various optical illusions; images of each surface they studied are available at the web address provided in the citation, below.  The researchers report that “Participants walked across four flat floors, each comprising of a visual illusion: two patterns perceived as alternating 3D “furrows and ridges,” the Primrose Field illusion, and a variant of the Cafe Wall illusion as a control pattern without perceived 3D effects. Participants found all patterns intriguing to look at; some describing them as ‘playful’ or ‘gentle.’ More than half found some of the patterns uncomfortable to walk on, aversive, affecting walking stability, and occasionally even evoking fear of falling. . . . Overall, this exploration and the differences in experiences it provoked for different patterns suggest that walking over floors containing high-contrast patterns such as the visual illusions used here might affect people’s walking experience -- often, but by no means always, in a negative way.”    
• Research indicates that the stripes on zebras tend to reduce the likelihood that the animals will be bitten by horse flies; designers can apply this finding when selecting patterns for vertical surfaces.  Caro and teammates (2019) determined that “Averting attack by biting flies is increasingly regarded as the evolutionary driver of zebra stripes. . . . We examined the behaviour of tabanids (horse flies) in the vicinity of captive plains zebras and uniformly coloured domestic horses living on a horse farm in Britain. Observations showed that fewer tabanids landed on zebras than on horses per unit time. . . . In an experiment in which horses sequentially wore cloth coats of different colours, those wearing a striped pattern suffered far lower rates of tabanid touching and landing on coats than the same horses wearing black or white, yet there were no differences in attack rates to their naked heads. . . . Taken together, these findings indicate that, up close, striped surfaces prevented flies from making a controlled landing but did not influence tabanid behaviour at a distance.”  

Colors Together

As Ou (2015) notes some color combinations seem more harmonious or pleasing than others: “Colors having the same hue tend to appear harmonious. . . . Colors having the same chroma [saturation] tend to appear harmonious. . . . Small lightness variations between the constituent colors in a color pair may reduce the harmony of that pair. . . . The higher the lightness value of each constituent color in a color pair, the more likely it is that this pair will appear harmonious.”  Also, colors that differ only in lightness are harmonious combinations.   Additionally, “If the lightness difference increases, then the color-harmony score also increases. . . . Highest color-harmony scores are produced by colors having small chroma differences.  Color combinations of a high chroma difference produce lower color-harmony scores. . . . Similar hues produce high color harmony scores.”  In other words, combinations of colors that are matched/similar in hue or saturation are best, while small lightness differences can reduce the pleasingness of combinations, but color lightness among sets of colors is desirable and colors that differ only in lightness are harmonious.  

Jeon, Han, and Namstudied (2020) evaluated how preferences for particular color vary.  They report that “designers and marketers often use a mix of colors whose harmony must be taken into consideration, which includes choosing whether to use colors placed next to each other on the color wheel (analogous combination) or to combine colors that are opposite each other (complementary combination). . . . Individuals with interdependent [with other people] self-construals tend to focus on relational similarity and value harmony, whereas individuals with independent [apart from other people] self-construals tend to view objects as discrete and disconnected. Accordingly, the authors posited that individuals with interdependent self-construals would be more sensitive to the relationship between two colors and perceive analogous colors as more harmonious, thus preferring brands and products featuring analogous colors to those featuring complementary colors. Contrariwise, individuals with independent self-construals would display indifference in this regard. The hypotheses were confirmed in four studies employing various colors to form analogous and complementary color combinations.”

Serra, Gouaich, and Manav (2022) assessed preferred surface color combinations (2022).  They share that they “explored the similarity/contrast . . . on the walls of a simulated interior of a bedroom from the Swiss Pavilion (Le Corbusier, 1930-1931). Participants were 644 students of architecture and interior design in Western Europe and Near East, who evaluated with a Likert scale their preference for virtual images via an online survey. Results indicate that the most preferred color combinations are those with hues closer in the color wheel, being the similarity between hues in the backgrounds more important than in the accent colors, and with NCS B30G to G as the most preferred hues. Observers preferred color compositions with blackness under 10% and similar blackness between the two background colors, together with a certain blackness contrast between these background colors and the two color accents. Similarly, observers liked color compositions with low chromaticness and low chromaticness difference among the four colors of the composition.”

TakeAway

Seeing surface patterns and sets of colors used together affects how we think and behave in meaningful ways.

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