Neuroaesthetics: The Human Evolutionary Preference for Symmetry and Luster
The attraction to luster is rooted in our evolutionary history and has persisted among prehistoric artifacts, ancient civilizations, and consumer culture.
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Introduction[edit | edit source]
The preference for glossy and lustrous surfaces is a significant aspect of human expression in aesthetics and artistic representation. Our ancestors’ ability to recognize water sources was crucial to their survival. As a result, the attraction to lustrous materials is deeply rooted in our evolutionary history and has persisted among prehistoric artifacts, ancient civilizations, and modern consumer culture.
Neuroaesthetics and Symmetry[edit | edit source]
The neuroscience of aesthetics examines how the brain processes beauty and certain forms through connected neural systems. Research indicates there are three systems surrounding aesthetic appreciation: the emotion-valuation system, the sensory-motor system, and the meaning-knowledge system.
The emotion-valuation system processes reward and pleasure and heavily involves the orbitofrontal cortex, which assists in decision-making, the amygdala, which is responsible for emotion processing, and the ventral striatum, which is heavily linked to reward. This system makes it possible for aesthetic experiences to be emotionally significant. The sensory-motor system interprets visual stimuli, engaging the primary and secondary visual cortices and certain premotor areas, which help guide movements. This system allows us to recognize aesthetic patterns and respond to them. The meaning-knowledge system assigns context and significance to aesthetic experiences, involving the anterior temporal lobe—which provides meaning to sensory input, and the medial prefrontal cortex, which is important for executive functions, such as decision-making, and the expression of our personalities. This system is responsible for integrating past experiences and learned associations to “see” deeper narratives within artistic expressions. Together, these three systems create a framework that helps us process and respond to beauty.
Certain forms stimulate mu receptor cell groups and are pleasing to look at. One such pleasing form is symmetry. In the broadest sense, symmetry indicates that something remains the same despite a change in orientation. Studies in evolutionary psychology suggest that the preference for symmetry is imbued in our neural processing, as symmetrical patterns activate specific regions of the visual cortex and are processed more quickly and efficiently than asymmetrical patterns. The ability to recognize and create symmetrical forms is linked to broader cognitive functions, such as spatial reasoning, motor coordination, and visual processing.
Mirror symmetry, or symmetry of a reflection, is thought to have special significance in human perception as it mimics natural structures, organisms, and animals. The ability to discern this type of symmetry is likely hardwired; humans can accurately discern symmetrical objects in less than a twentieth of a second. Human infants can distinguish between mirror symmetry and other complex symmetries when they are as young as four months old, suggesting that this ability is inborn. Useful for identifying animal-like forms, the ability to recognize mirror symmetry quickly was likely a crucial survival skill. The detection and preference for symmetry are also present in other animals, such as monkeys, raccoons, and birds, though humans can detect it more quickly and accurately than other primates, like macaques. The visual array found in nature also has more horizontal and vertical lines than lines in other orientations, which likely is the reason why animals prefer these lines and types of symmetry.[1]
The hardwired preference for symmetry may have originally evolved for survival purposes, such as identifying healthy mates and distinguishing between animate and inanimate objects, but later became a central element in our art and material culture. Evidence from archaeological sites suggests that symmetry was incorporated deliberately into certain early traditions.
Case Study: Symmetry in Acheulian Handaxes[edit | edit source]
The Acheulian tradition, dating back approximately 1.6 million years, saw multiple hominin species such as Homo erectus and Homo heidelbergensis producing Acheulian handaxes. Early specimens were primarily functional, but handaxes produced later were made with increasing attention to and refinement of their bilateral symmetry. This preference for symmetry is found to have begun among Acheulian handaxe examples after 500,000 BP (before the present). After this time, the shape became more refined, with a greater concern for mirror symmetry and other types of symmetry.
Various parts of the brain become activated when a modern flint knapper makes a symmetrical Acheulean handaxe. The premotor cortex, responsible for movement planning and sorting information from visual sensory cues for spatial orientation, becomes notably active. Interestingly, the same areas are active, but to a lesser degree, when making simpler tools that are in line with the earlier Oldowan tradition.[2] Acheulian handaxe production exhibits one of the earliest and most enduring expressions of the human preference for symmetry. Still, it was not the only expression of symmetry of its time. “Spheroids,” or stone balls, which date back to around 1.5 million years ago, were also created with significant consideration to symmetry. Hominins, including Neanderthals, invested more time and effort than was necessary to manufacture these stone tools and spheroids, as non-symmetrical versions were still functional, which alludes to the fact that these refinements were made for aesthetic purposes.[3]
Inherent Preference for Lustrous Surfaces[edit | edit source]
The attraction to glossy, polished, and shimmering surfaces is another aesthetic preference among humans. Just as symmetry has been favored in material culture and general visual perception, luster and gloss are also often sought out.
Previously, some researchers assumed that children’s preferences in what they consider attractive were highly influenced by their exposure to and consumption of media, which is created by adults with innate and learned preferences. However, other research has found that many aesthetic preferences, especially regarding human faces and animal faces, may be present in early infancy.[4] Researchers Katrien Meert, Mario Pandelaere, and Vanessa M. Patrick conducted a series of experiments—published in the Journal of Consumer Psychology in 2014—to expand upon the innate quality of certain aesthetic preferences and establish that there is an inherent preference for glossy surfaces.
The first experiment demonstrates the preference for glossiness among both adults and children. Four leaflets were given to 36 participants, half printed on glossy paper and the other half on matte or non-glossy paper. The participants were asked to arrange the leaflets according to their preference, and the results showed a statistically significant preference for glossy leaflets over non-glossy ones. The latter half of the first experiment investigated the preference for glossiness in young children, using eight pictures of Santa Claus instead of leaflets, half of which were glossy and the other half non-glossy. After the children ranked their first, second, and least favorite pictures of Santa, the results showed a significant preference for the glossy pictures over non-glossy, albeit lower than that in adults.
Because the content of a presented image may affect children’s preferences more than that of adults and the fact that luxuriousness may be attributed to glossy surfaces over time, the second experiment tested whether the preference for glossiness in adults was related to the content of the images presented on glossy paper. A random combination of four landscapes was provided to 112 participants, half printed on glossy paper and the other half on non-glossy paper, and they were asked to evaluate either the image’s content, the type of paper, or both. The type of paper influenced the responses of all respondents, and glossy images obtained a higher “liking” score.
When the type of paper changed, all participants changed their preferences to the image on glossy paper, irrespective of the participants’ previous choices. These results showed a powerful preference for glossy images regardless of the depicted landscape.[5] Overall, the two studies showed that liking glossiness manifests before any exposure to contemporary cultural stereotypes.
Evolutionary Basis for the Preference of Glossy Surfaces[edit | edit source]
Locating water is an ancient skill shared across the animal kingdom, and for early nomadic humans, successfully encountering freshwater sources was a matter of life or death. The necessity of water is fundamental to survival, as humans can only live a few days without it, and an inadequate water intake over 24 hours may increase the risk of dysfunctional metabolism and chronic disease.[6] Water has been a critical resource for human survival and evolution, influencing migration patterns and natural selection.
During the Pliocene Epoch, global climates shifted. Hominins at this time likely traveled between semi-permanent rain pools, restricting their movements to warmer and wetter regions. During the Late Pleistocene, humid forests declined and grassland-savanna habitats expanded.[7] Thus, the ability to detect water sources became even more important. In the dry savanna conditions of East Africa, early humans relied on small lakes and rain pools to survive seasonal droughts, and fossil evidence suggests that many hominid remains have been found near ancient lakeshores, supporting the idea that access to water played a key role in early human dispersal. The savanna hypothesis suggests that the expansion of African grasslands was driven by climate change, which led to the divergence of hominins from apes and led to the emergence of the genus Homo.[8]
Natural selection likely led to choosing individuals who could recognize water and wet surfaces, and, according to evolutionary anthropologist Dean Falk’s radiator theory, the success of finding drinking water daily to prevent the stressors surrounding dehydration played a substantial role in shaping hominin evolution in favor of greater energy efficiency.[9]
Water significantly impacts our neurological system, influencing physiological and psychological well-being states. Psychology professor Richard Coss and his former student, Craig Keller, conducted a pair of studies, published in the Journal of Environmental Psychology in 2022, showing that “gazing at bodies of water can help lower your heart rate, blood pressure, and increase feelings of relaxation.”[10]
The first of Coss and Keller’s studies investigated whether viewing water would cause reward by decreasing blood pressure and heart rate compared to viewing urban features without water. The study showed that viewing a swimming pool lowers heart rates versus viewing a street sign and a tree in a parking lot. The same trend was true for blood pressure, which decreased significantly when looking at the swimming pool.
The second study measured heart rate and blood pressure when viewing six sites with different amounts of visible water. Overall, viewing water compared to the adjacent ground produced reliable physiological effects consistent with a transient relaxation response, or a decrease in heart rate and blood pressure. Moreover, the studies found that viewing wider portions of water produced higher subjective states of relaxation than narrow portions of water, suggesting that abundant amounts of water have a greater potential to limit dehydration. Clear water also produced a higher subjective state of relaxation than murky water did, which may be linked to the health of the water. Clear water is less likely to contain potentially harmful bacteria and produce an unfavorable future state.[11]
A separate, 2010 study by Richard Coss investigated the connection between glossy surfaces and their association with water or wetness. Coss designed an experiment using four different papers with differing surface finishes: matte watercolor paper, glossy silk-screen paper, gritty sandpaper, and sparkly glitter paper designed to be reminiscent of an ocean surface. The study’s 139 participants were asked to examine, tilt, and assess the surfaces using a semantic questionnaire to asses their wet and dry connotations as well as their overall attitude toward each paper type.
The results demonstrated that glossy surfaces appear significantly wetter than sparkling surfaces, and both the glossy and sparkling surfaces were perceived as wetter than the matte and sandy surface finishes. The participants’ assessment of the sparkling surface, having been rated lower on the wetness scale than the glossy silk-screen surface, suggests that sparkle does not consistently indicate the presence of moisture despite captivating attention and being generally rated as attractive. This discrepancy may stem from the historical uncertainty regarding sparkling surfaces as an indicator of water since sparkly surfaces appear in both pools of water and dry materials, such as quartz crystals and other rocky formations.
The study’s findings reinforce the fact that glossy surfaces convey strong optical information about moisture, likely due to a selection that favored individuals who could accurately identify wet environments. Sparkly surfaces, while being visually stimulating, do not reliably indicate wetness unless they are accompanied by a glossy visual texture. Gender differences emerged in the study, with women rating the sparkly glitter paper as more attractive than men, but they did not interfere with the wetness ratings of each paper. Overall, this research suggests that attraction to glossy surfaces stems from an innate need for water, and the links between visual perception and survival instincts are associated with water detection.[12]
Researchers Katrien Meert, Mario Pandelaere, and Vanessa M. Patrick took the study of the desirability of glossiness and its association with fresh water one step further by hypothesizing that participants would prefer images on glossy paper even more when they were thirsty. The results from this experiment in the paper “Taking A Shine to It: How the Preference for Glossy Stems From an Innate Need For Water” showed that while being thirsty may not be needed to increase preference for glossy images, thirst did significantly affect the participants’ preference for glossy images over non-glossy ones.
Qualities of Art and the Pursuit of Luster in Prehistoric Humans[edit | edit source]
The Aurignacian culture was a culture surrounding toolmaking and artistic innovation in Europe during the Upper Paleolithic period, marked by a greater diversification of tools and an increase in the use of lithic or stone flakes, rather than lithic blades, to make tools. This culture spread from the Atlantic Coast to the Iranian Plateau and Western Eurasia and spanned from 43,000 to 30,000 years ago, during which Homo sapiens produced objects of artistic representation.
Though there is debate over what is considered “art” within the archaeological record, archaeologist Randall White argues in favor of George Mills’s definition from the article “Art: An Introduction to Qualitative Anthropology” that, in essence, art is the “controlled qualitative experience.” This definition includes the appeal to aesthetic principles, the capacity to be evocative, and the potential for metaphorical interpretation to be essential qualities of art.[13]
Some of the earliest evidence of art and artistic representation in the archaeological record comes from the Middle Stone Age. In Africa, the Blombos Cave in South Africa produced hematite artifacts with geometrically incised lines, placed intentionally. In Fumane, Italy, Neanderthals are thought to have used feathers for ornamental purposes. Later on, during the Upper Paleolithic, the Aurignacian culture advanced artistic representation in terms of abundance and technique.
Members of the Aurignacian culture consumed a large amount of reindeer/caribou and produced many adornments crafted from animal bones. However, the record for the animals they ate differs from the animals they wore, as their adornments were not made from reindeer bones but from those of other animals such as foxes, wolves, hyenas, large cats, and bears. This indicates a preference for certain materials for creating ornamental objects. An even stronger preference shown by the archaeological record was that of using lustrous materials to create art and adornments.
Luster is a common shared quality of predominant raw material chosen by the Aurignacian to make personal ornaments with.[14] Such raw materials included ivory, soapstone, talc or chlorite, amber, mother of pearl, and even polished tooth enamel from adult human teeth. Ivory is lustrous when manipulated through polishing and was often encountered during this period, especially in the form of basket-shaped beads. Soapstone had no technological purpose and was not found anywhere before the Aurignacian culture, yet it was sourced from the faraway Pyrenees Mountains, presumably for its surface and visual appeal. Talc and chlorite have a soapy texture when polished and were also moved across landscapes. The Aurignacian also produced some of the oldest known amber pendants. Lastly, the mother of pearl is a shiny, iridescent material formed by mollusks and used for adornment by humans.
According to Randall White, early humans manipulated materials specifically to create visual pleasure, which is showcased well by the early humans of the Aurignacian culture, who actively sought out and crafted objects with a lustrous sheen. In this case, the “controlled qualitative experience” was the pursuit of lustrous surfaces. The Blombos Cave in South Africa, which produced early evidence of artistic representation and dates from 82,000 to 75,000 years ago, also produced evidence of the preference for glossy textures even before the Aurignacian culture. An analysis of 28 bone tools from the cave identified three carefully polished points. The high polish gives a distinctive appearance to these artifacts, but the high shine has no apparent function and was likely done to give the points “added value.”[15]
Case Study: Upper Paleolithic Lustrous Gravels in Prehistoric France[edit | edit source]
Excavations across multiple archaeological sites in southwestern France have uncovered polished, spherical gravels dating to the Upper Gravettian and Solutrean periods. These gravels are interesting because of their lustrous appearance and, in some instances, deliberate placement. The 2023 journal article “Multiproxy Analysis of Upper Paleolithic Lustrous Gravels Supports Their Anthropogenic Use” studied key sites such as Fourneau du Diable, Casserole, Pech de la Boissière, Laugerie Haute, and the Landry site, which was excavated in 2011.
The Landry site dates to approximately 21,500 years ago and yielded 106 gravels from just one of its sectors. The Fourneau du Diable site yielded a large number of lustrous gravels, with 465 discovered gravels from the Gravettian and Solutrean layers, along with 409 from the Late Solutrean, emphasizing the widespread use of these objects in the area. At this same site, 136 gravels were found in a peculiar arrangement: neatly placed in nine rows of 15 gravels each, forming a rectangular pattern. Their arrangement and careful placement suggest that they were originally affixed to a chest or other structured object made from perishable material. The other sites, Pech de la Boissière, Casserole, and Laugerie Haute, also contained lustrous gravels but in significantly smaller quantities. Thirty, 14, and 37 polished gravels were found in the Solutrean layers, respectively.[16]
Detailed analysis of these gravels confirms that their polished surfaces were intentional modifications rather than resulting from natural weathering, as “the wear pattern on archaeological gravels is absent on natural gravels.” Experimental replication of the polishing process was done by tumbling gravels with animal skins or leather, ocher, and fat. In contrast, the abrasion against the Landry silt did not produce the same results. Thus, environmental causes of weathering, such as water and wind transport and abrasion against local silts, therefore can be ruled out. Furthermore, the uniform amount or degree of shine on each archaeological gravel supported the hypothesis that they were deliberately selected, manipulated, and curated over time. There was a high concentration of lustrous gravels in areas associated with domestic activities, suggesting that their placement was not random but purposeful and meaningful within prehistoric communities. Their distribution reflects that the accumulation of gravel was due to intentional human activity rather than any natural process.
Worldwide, pebbles have been used as talismans and amulets to embody spirits and ancestors. Though the precise function of the polished gravels remains uncertain, ethnographic comparisons to and between other cultures provide insight into their potential uses in southwestern France. Some gravels were likely used for magico-religious purposes as sorts of charms, tools for divination, or elements of ritual activities. For the Aranda people of Australia, pebbles were thought to have strong magical powers and were worn around the neck in small pouches to keep them secure.
Other gravels may have been incorporated into musical instruments, producing rhythmic sounds when shaken in rattles or vessels. An example of polished pebbles used in musical instruments was found at the Jiahu site in China.[17] At the site, the skeleton of a male, aside from the skull, was found alongside a turtle shell with polished pebbles inside it. Such musical instruments or noisemakers may have also had a ritual purpose.
Pebbles have also been used as a tool in hunting, fishing, crafting, or as weights. In the Innu culture of eastern Canada, women’s tools included a small sack of pebbles to give additional force to scrapers when removing fat from animal hides. Another potential use for pebbles was as game pieces during social activities. Small pebbles were also used among hunter-gatherer communities for medicinal practices, counting tools, status markers, and weaponry.
The deliberate selection and modification of these gravels indicate that humans during the Upper Paleolithic actively pursued and valued lustrous surfaces. The gravels’ absence in earlier layers suggests that their associated function was an aspect of human culture that emerged during the Gravettian period and continued into the Solutrean. These findings align with the broader evidence of prehistoric humans’ appreciation of shiny and lustrous surfaces.[18]
The Legacy of Lustrous Surfaces[edit | edit source]
Many ancient civilizations flourished on riverbanks and in river valleys, such as the Sumerians and the Indus Valley Civilization—reliable access to fresh water supported agriculture, trade, and large population growth. The evolutionary preference for both water and glossy surfaces remains evident in modern human behavior, as many modern cities are situated near water, and the pursuit of shine persists.
People are consistently drawn to landscapes featuring water in both reality and paintings. Children prefer paintings depicting water as a central element even at a young age, according to a study published in the Journal of Environmental Psychology in 1983.[19] Real estate trends also reflect this deeply ingrained bias, as homes with aquatic views, whether lakes, rivers, or oceans, are significantly more desirable and often valued at higher prices. A pair of studies published in 2010 investigating preferences in both natural and built environments showcased a strong preference for those incorporating aquatic features and a stronger willingness to book a hotel room with aquatic views.[20] Individuals also tend to associate water with positive memories, linking it to childhood experiences, including swimming, fishing, and playing near streams.[21]
The association between glossiness and luxury is prevalent in modern marketing strategies. Research by Rui (Juliet) Zhu and Joan Meyers-Levy explores how display surfaces influence the perceptions of products from the consumers’ perspective. They demonstrated that the material beneath a product can alter how trendy, natural, or modern it appears. Though the consumer’s self-view plays a role in these perceptions, the results of the study suggest that the glossiness of a store display, when comparing shiny glass versus wood, has a positive impact on the products displayed on it and increases the connotation of modernity.[22]
Potential Applications[edit | edit source]
Water and our gravitation toward its associated textures have shaped our aesthetic preferences and many aspects of our material culture. For instance, landscape paintings and photographs often depict water or water-like imagery. Urban space architecture and design sometimes incorporate water features such as fountains and pools. As previously mentioned, water features evoke more positive responses in built structures. The connection between survival, comfort, and glossy surfaces can be further leveraged in various design and mental health applications beyond aesthetics.
Author Wallace J. Nichols explores water as a “therapeutic landscape” in his book, Blue Mind, which analyzes studies that suggest being near water can have powerful effects on the human psyche.[23] The book provides evidence that water generates a meditative state more powerful than hypnosis techniques and makes us healthier, happier, and more creative.
Thus, integrating water features into the urban planning process can enhance the well-being of city dwellers. Since water elements can reduce stress and promote relaxation, they become valuable additions to parks and residential centers. In interior design, glossy finishes and reflective surfaces can have a similar relaxing effect. Water-like reflections can create soothing spaces in hospitals and rehabilitation centers.
Understanding the evolutionary basis of the preference for symmetry, gloss, and luster can allow designers and mental health professionals to create environments that align with our deeply rooted preferences. As neuroscience continues to emerge in the design landscape, designers can use scientific advancements to create better designs that consider their impact and potential benefits on human emotions and psychology.
- ↑ Meneganzin, Andra, and Killin, Anton. (2024). “Beyond Reasonable Doubt: Reconsidering Neanderthal Aesthetic Capacity.” Phenomenology and the Cognitive Sciences.
- ↑ Stout, Dietrich; Toth, Nicholas; and Schick, Kathy. (2006). “Comparing the Neural Foundations of Oldowan and Acheulean Toolmaking: A Pilot Study Using Positron Emission Tomography (PET).” Toth, Nicholas and Schick, Kathy (eds.), The Oldowan: Case Studies in the Earliest Stone Age. Stone Age Institute Press, pp. 321-331.
- ↑ Wynn, Thomas, and Berlant, Tony. (2019). “The Handaxe Aesthetic.” In Squeezing Minds From Stones: Cognitive Archaeology and the Evolution of the Human Mind, Overmann, Karenleigh A. and Coolidge, Frederick L. (eds.) New York: Oxford Academic.
- ↑ Langlois, Judith H.; Roggman, Lori A.; and Rieser-Danner, Loretta (1990). “Infants’ Differential Social Responses to Attractive and Unattractive Faces.” Developmental Psychology. Vol. 26, No. 1, pp. 153-159.
- ↑ Meert, Katrien, Pandelaere, Mario, and Patrick, Vanessa M. (2014). “Taking a Shine to It: How the Preference for Glossy Stems From an Innate Need for Water.” Journal of Consumer Psychology. Vol. 24, No. 2, pp. 195-206.
- ↑ Armstrong, Lawrence E., and Johnson, Evan C. (2018). “Water Intake, Water Balance, and the Elusive Daily Water Requirement.” Nutrients. Vol. 10, No. 12.
- ↑ Smail, Irene E.; Rector, Amy L.; Robinson, Joshua R.; et al. (2025). “Pliocene Climatic Change and the Origins of Homo at Ledi-Geraru, Ethiopia.” Annals of Human Biology. Vol. 52, No. 1.
- ↑ Bobe, René, and Behrensmeyer, Anna K. (2004). “The Expansion of Grassland Ecosystems in Africa in Relation to Mammalian Evolution and the Origin of the Genus Homo.” Palaeogeography, Palaeoclimatology, Palaeoecology. Vol. 207, Issues 3-4, pp. 399-420.
- ↑ Falk, Dean. (1990). “Brain Evolution in Homo: The ‘Radiator’ Theory.” Behavioral and Brain Sciences. Vol. 13, No. 2, pp. 333-344.
- ↑ Coss, Richard Gerrit, and Keller, Craig. (2022). “Transient Decreases in Blood Pressure and Heart Rate With Increased Subjective Level of Relaxation While Viewing Water Compared With Adjacent Ground.” Journal of Environmental Psychology. Vol. 81, Issue 3.
- ↑ Orians, Gordon H., and Heerwagen, Judith H. (1992). “Evolved Responses to Landscapes.” In Barkow, Jerome H.; Cosmides, Leda; and Tooby, John ( eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, pp. 555-579. Oxford University Press.
- ↑ Coss, Richard G. (1990). “All that Glistens: Water Connotations in Surface Finishes.” Ecological Psychology. Vol. 2, No. 4, pp. 367-380.
- ↑ Mills, George. (1957). “Art: An Introduction to Qualitative Anthropology.” The Journal of Aesthetics and Art Criticism. Vol. 16, No. 1, pp. 1-17.
- ↑ White, Randall. (2007). “Systems of Personal Ornamentation in the Early Upper Palaeolithic: Methodological Challenges and New Observations.” Rethinking the Human Revolution: New Behavioural and Biological Perspectives on the Origin and Dispersal of Modern Humans, pp. 287-302. McDonald Institute for Archaeological Research.
- ↑ d’Errico, Francesco., and Henshilwood, Christopher S. (2007). “Additional Evidence for Bone Technology in the Southern African Middle Stone Age.” Journal of Human Evolution. Vol. 52, No. 2, pp. 142-163.
- ↑ Geis, Lila; d’Errico, Francesco; Jordan, Fiona M.; et al. (2023). “Multiproxy Analysis of Upper Palaeolithic Lustrous Gravels Supports Their Anthropogenic Use.” PLOS One.
- ↑ Zhang, Juzhong; Harbottle, Garman; Wang, Changsui; et al. (1999). “Oldest Playable Musical Instruments Found at Jiahu Early Neolithic Site in China.” Nature. Vol. 401, pp. 366-368.
- ↑ Geis, Lila; d’Errico, Francesco; Jordan, Fiona M.; et al. (2023). “Multiproxy Analysis of Upper Palaeolithic Lustrous Gravels Supports Their Anthropogenic Use.” PLOS One.
- ↑ Zube, Ervin H.; Pitt, David G.; and Evans, Gary W. (1983). “A Lifespan Developmental Study of Landscape Assessment.” Journal of Environmental Psychology. Vol. 3, No. 2, pp. 115-128.
- ↑ White, Mathew; Smith, Amanda; Humphryes, Kelly; et al. (2010). “Blue Space: The Importance of Water for Preference, Affect, and Restorativeness Ratings of Natural and Built Scenes.” Journal of Environmental Psychology. Vol. 30, Issue 4, pp. 482-493.
- ↑ Waite, Sue. (2007). “‘Memories Are Made of This’: Some Reflections on Outdoor Learning and Recall.” Education. Vol. 35, No. 4, pp. 333-347.
- ↑ Zhu, Rui (Juliet), and Joan Meyers-Levy. (2009). “The Influence of Self-View on Context Effects: How Display Fixtures Can Affect Product Evaluations.” Journal of Marketing Research. Vol. 46, No. 1, pp. 37-45.
- ↑ Nichols, Wallace J. (2014). Blue Mind: The Surprising Science That Shows How Being Near, In, On, or Under Water Can Make You Happier, Healthier, More Connected, and Better at What You Do. Little, Brown.
