Evolutionary Importance of People-Plant Relationships PDF

 Chapter 18 The Evolutionary Importance o f People-Plant Relationships Charles A. Lewis In the first symposium we considered the effect of plants in creating and maintaining human well-being and social develop...

 Chapter 18 The Evolutionary Importance o f People-Plant Relationships Charles A. Lewis In the first symposium we considered the effect of plants in creating and maintaining human well-being and social development. To delineate the ways in which humans respond to vegetation the speakers approached the topic from several views; historical-cultural, psychological, physiological and sociological. Researchers presented their findings about the kinds of landscape scenes that people prefer to see. We learned of the restorative qualities of green settings. In hospitals, a view of trees helped patients to recover more quickly than patients without such a view, hi a number of diverse situations the presence of plants helped people to feel better about themselves and where they lived. The first symposium clearly established the validity of people/plant interactions and pointed the way to further consideration of human issues in horticulture. Today we will take a closer look at the human preferences for green settings and see if we can find their origin. Why is green so attractive to people? How did we get that way? Since the expression of likes and dislikes, preferences, are reflections of mental attitudes, we will not only be concerned with the green settings but how those settings echo in our consciousness; how our innate thinking patterns about vegetation might have become set within us. Much of the information in this paper is taken from a forthcoming book. Green Nature, Human Nature, by Charles Lewis published in 1993 by Jeremy R Tarcher, Inc., member of The Putnam Berkley Group, Inc. © 1994 by The Haworth Press, Inc. All rights reserved. 239 240 People-Plant Relationships: Setting Research Priorities To do this we will have to consciously examine an unconscious part of ourselves, our mind which shapes and interprets everything that we expe- rience-see, hear, taste, smell, or touch. Mind is a personal expression of our brain, a many layered organ which has developed as we have over the millennia of evolution. In thinking about our mind it is interesting to consider some of the ways in which it functions. We can intentionally direct our thoughts as when we focus our mind on solving a problem, or our mind can operate in a more spontaneous manner as when feelings and thoughts present themselves without our consciously calling them forth as when we experience a beautiful sight. It would appear that from a mental viewpoint we really are two people. One is the obvious physical thinking person who walks about in this world making decisions and controlling what happens around him/her. The other is a hidden self which expresses itself through innate responses to the world which do not come out of conscious thought but seem to be stored some- place else and show themselves in unexpected ways. We all have had the experience of walking down a street and suddenly a car behind us honks its hom, startling us. Immediately our heart starts to beat more quickly and we gain a new level of alermess. In a lecture hall all eyes are focused on the speaker, however, should someone appear at the side of the stage, all audience eyes would immediately turn to look at the newcomer. Often when seeing spiders, snakes and other creatures, people will experience a revulsion, and in frightening situations feel the hairs on the back of their neck “ standing up. ” These are all innate responses which occur not because we first thought out the situation and then decided on the appropriate behavior, but rather because someplace deep inside us these patterns of behavior were already “ built in,” programmed, part of the essential human. They lie in our subconscious, triggered, ready to express themselves whenever appropriate circumstances occur. These innate responses often make no sense in a contemporary context, but they serve to remind us that we did not originate in the contemporary world. A close examination reveals that within our contemporary selves there lies hidden an ancient self that was programmed in primitive times for survival under those conditions. Today it continues to respond to stimuli creating echoes of an earlier time when such signals were impor- tant for survival of the individual. Understanding these ancient responses and satisfying them helps to bring our two selves-ancient and contempo- rary-into harmony and reduce the stress resulting from denial of basic intuitive needs. If we are to understand ourselves today, it is necessary to seek the remote origins of these responses. How might ^ y have helped us to survive in primitive environments?  Plants and the Individual 241 We can gain a view of this hidden self by considering body knowledge, wisdom stored in each of us which helps us to survive each day. If we cut a finger, we do not have to stop and diink of all the steps and materials required to heal the wound, stop the bleeding, create a scab, and begin to form new skin. The body “ knows” how to do i t When we see blood, our blood pressure is automatically lowered, reducing the chance of excessive bleeding. Body knowledge is ancient information encoded in our genes. Through eons of evolution this wisdom, essential for continued survival, has accumulated within us and is ready to act the instant it is needed. In every second of life our bodies act without our conscious instructions, performing a multitude of functions to maintain an internal homeostasis. Body knowledge is able to signal important needs through feelings. Pain, thirst, and hunger alert us to be aware, call attention to something impor- tant. Body wisdom knows what is needed and responds immediately. Similarly, we might consider our emotional responses to nature settings as the psychic equivalent of body knowledge, something which helped us survive at a time past, but to which we continue to respond today. Is there an ancient meaning in our love for the blazing display of fall color, the fresh bloom of plants and trees in the spring? Perhaps these emotional responses, too, played an important role in our survival and, like body knowledge, were locked in our genes. How might we examine this ancient past? Where do we come from, what influences may have shaped our journey from its dim begiimings to today? Archaeologists, anthropologists and historians study physical arti- facts to tell us how we looked, what we built, the kinds of societies we developed and the events that moved us through history. But how can we study the role of our non-physical selves-how we thought, felt and reacted as primitives in a primitive environment? There are no physical artifacts to help us here, but rather, we must look at our contemporary selves to see if we can discern traces of the persona of that earlier life. Psychologists find evidence in contemporary patterns of re- sponse which are consistent across social, economic, cultural and racial boundaries. When found, these widespread responses can be assumed to be irmate in the human psyche, and not the result of contemporary cultural conditions. PREFERENCES FOR NATURE Our ancient innate needs and our culturally influenced responses are like two threads, the warp and woof of the human fabric. Our intuitive likes and dislikes for what we see can be the threads that will lead us back 242 People-Plant Relationships: Setting Research Priorities to our ancient selves and provide access to the origin of those innate feelings. Years of research by environmental psychologists and geographers have clearly established that the presence of green is a strong indicator for preference. When vegetation is added to a previously low ranked urban scene its preference is raised. There seems to be something about the presence of green that is important to people. Researchers find a consisten- cy in preference for vegetation among populations that may differ eco- nomically, culturally and geographically. TUs is an indication that what is being measured is not a function of the culture in which people live but rather is something that is inherent in humans, irrespective of who they are and where they live. What is there about the presence of green nature that elicits preference? The researchers conclude that these settings must provide a kind of in- formation that is important to us at a deep level. Stephen Kaplan conceptu- alizes humans as information-processing beings-taking in what we find through our senses, then interpreting and using that information as a basis for decisions.* Therefore we can conclude that the expression of landscape preferences must somehow be connected with gaining and processing information. EVOLUTION: PEOPLE AND PLANTS To find the origin of the meanings of landscape preferences, we will have to look back to our beginnings as a species and the ways in which survival information was gained from the surrounding environment. We cannot see the begiiming and certainly there were no psychologists to test our humanoid ancestors, but we can use the best available information to reconstruct the scene; wherever humans appeared on the planet, what they found, and what they needed to survive and reproduce. In the grand scale of evolution of life on this planet, humans represent but a blip. Our time on Earth is estimated at 100 million years of evolution as a mammal, over 45 million years as primate, over 15 million years as an ape, and 2 million years as homo sapiens. Biologist Richard H. Wagner places us in a proper perspective. He says, “ If you were to consider evolution of life on earth as a 30 minute film, you would see wave after wave of new species evolving, filling the environ- ment with a diversity of life forms, and then receding-sometimes totally, but occasionally leaving a few of the best adapted species behind. It is humbling to note that man’s existence on earth would flash by in the last 3.5 seconds of that film!  Plants and the Individual 243 Humans evolved in a world already populated with a wide diversity of green plants. Learning to survive must have been a full-time task. Only those who were successful were able to produce offspring and carry on the species. Individuals who were not successful were dead ends in the evolu- tionary process. In addition to the daily instinctive needs for food and water, early humans had to locate a suitable habitat to serve as a nesting site, to provide shelter and protection for offspring. We continue to see the instinctive nesting and courting behaviors in animals and birds that led to their evolutionary survival. Might there be an analogous remnant of our beginnings? In addition to instinctive responses, our primitive predecessors were endowed with an enlarged brain and thus gained the ability to think, analyze situations and make decisions-^lan for the future. In an environ- ment that could both sustain and threaten, they had to learn how to distin- guish settings that offered positive opportunities. Lacking a guide book, humans had to seek in their surroundings the clues which spelled survival. The green environment itself became the source of information on its suitability for sustaining human life. Those successful at learning joined the company of their predecessors that con- tinued the species. Making Sense Out o f What Is Seen At some point in time our humanoid ancestors started to move down from trees to live on the ground. Gurrent evidence suggests the African Savanna as locale of this change. They went from a multidimensional boreal life in the trees where they could move freely up, down, or out-to an environment which starts and ends at the ground. The change in habitat required an adjustment to the comparatively linodted dimensions of life on the ground. In a savanna already inhabited, the new arrivals had to depend on their ability to outthink those who already lived there. Early humans had to learn how to fend for themselves against all the odds presented in the natural environment. Though slower afoot and physically smaller, they utilized their larger brain capacity to outwit the animals surrounding them, imagine what might happen before it happened, and plan their response to any possible situation. They had to become skilled at discerning those settings which offered opportunities for success. How might hunter-gatherers analyze a land- scape to determine its suitability for their group? Tlnough trial and error, repeated observation and analysis they learned to recognize and favor features in the surroundings which portend safety and to avoid those 244 People-Plant Relationships: Setting Research Priorities which offered danger. Only because our hunter-gatherer ancestors had mental capacities superior to the other life forms could they make judge- ments which required projecting into the future to predict the results of their actions. Only if they could make sense of what they saw would they be able to move to the next step and evaluate its potential for benefit or harm. Origin o f Landscape Preference The Roles o f Intuition and Cognition in Landscape Preference Let’s consider the mental steps that might be required in appraising a setting for its survival value. In the process two mental qualities, intuition and cognition, are utilized. Intuitive reasoning utilizes what has already been learned to produce a more instantaneous or automatic response. In cognition, a slower process, the mind thinks about and evaluates what is seen, reasoning comes into play, and it produces a projection of future implications of what is being seen. If the situation does not pose an im- mediate threat which would require an immediate decision, assessment can be a slower response with a larger cognitive component. How might this work? (1) Initially, one sees the setting and through thoughtful analysis makes sense of it, identifying parts of the landscape. (2) Through further thought processes one decides whether the environ- ment is favorable or unfavorable for one’s well-being. (3) The next deci- sion, based on the previous analysis, will be to take any action that might be needed. In the cognitive mode, assessment is slower, building piece by piece on what is learned, which is satisfactory if there is no impending threat that would require an immediate decision. However, if the situation is one with a potential for immediate danger or emergency, an efficient quick intuitive response would be more adaptive. For example, if a person were to hear a rustling in the bushes and then see a large form such as a mammoth, in a cognitive mode the sequence of thoughts might be: (1) Something in the bushes, it is big, it is a mammoth, it is moving, it is moving toward me-quickly! (2) Does this represent a threat? Yes and I had better do something about it-now! (3) Should I run away, or climb the nearest tree that would place me out of its reach? By the time the poor fellow had gone through this chain of thought to reach a decision, in all likelihood the mammoth would be on top of him and no further decision would be required. Not a very successful way of thinking! If, however, the whole process were to happen more quickly, (particu- larly steps 1 and 2), then there might be time enough to make a decision on what to do and execute it effectively. If steps 1 and 2 did not require  Plants and the Individual 245 conscious thought but were automatic, culminating in an emotional re- sponse, then the appraisal process would be speeded up. The only con- sciously thought out decision would be “ what should I do about it?” With this more efficient way of appraisal, one would have a better chance of surviving. Gordon Orians and Judith Heerwagen of The University of Washington in their study. Evolved Responses to Landscapes? differentiate between intuition and cognition when considering the steps our ancestors might have taken to sort out the dangers and benefits of a setting to decide if it is appropriate. When arriving in a new environment, the first decision is to stay and explore or to leave. This decision is based on an initial intuitive response, a generalized (gut) feeling about the place. Since the response is intuitive and does not require conscious thought, it is achieved quickly, almost instantaneously, and is therefore, highly efficient. Thinking processes are not tied up in this initial appraisal but are available for concentrating on other aspects, such as the threat of a challenging animal. The initial response is a quick automatic appraisal of the liveability of the place which includes assessment of the spatial features. For example, an open setting would not be desirable since it would offer no protection, nor would a closed setting of thick forest be desired since movement would be impeded and one could not easily see what was ahead in the tangle of trees and undergrowth. If the initial instinctive responses are positive, then the individual goes on to intentionally gather more information about the setting. At this more cognitive stage mental associations become important. The individual au- tomatically compares what is seen with any meanings it might call forth from memory of past experiences to provide a more detailed analysis of the habitat. The final stage of habitat selection culminates in a decision to stay. In making this decision one needs to be sure that the environment does indeed offer enough resources and protection to sustain life activities. Of particular concern would be food and safety. Is there evidence of animals that might be caught? Plants with fruits or other edible parts? Is the food so far away that it would take too much energy to catch it and bring it back to the group? Where is water? In assessing safety: are there places for escape if attacked by animals, trees to climb, caves in which to hide? Is the landscape open enough to see danger approaching? Does it offer high points where one can see broadly to determine what might lie ahead? If our hunter-gatherer ancestors would have been deeply involved in the 246 People-Plant Relationships: Setting Research Priorities analysis concentrating on assessing the surroundings to select a favorable habitat; while so involved they could have easily been surprised by unno- ticed appearance of dangers which crawled, roamed, or slithered in the surrounding environment. If, however, the entire process of habitat selec- tion were a more automatic response, then one’s mental faculties could remain alert to encounter the unpredictable. We have all had the experience of becoming so deeply involved in a mental activity-reading a book, working out a puzzle or problem-that we lose touch with what is happening around us. We could be unaware of someone who comes close and finally taps us on the shoulder, and when it happens, the interruption is startling, comes as a mild shock. However, when calling on what has already been learned, our minds can work simultaneously at more than one level. Learning a new skill, such as driving a car, requires intense concentration, particularly at the start. But once a skill is “ learned,” becomes part of our abilities, it is more automatic and requires less mental effort. All the activities of driving- steering, shifting, accelerating, watching out for other cars-happen almost unconsciously and we are able to attend to other things, glimpse the passing scenery or have a conversation with a passenger. What we have learned or know resides within our intellect and functions automatically, does not require an input of constant attention. Now, if in a similar way, our hunter-gatherer could somehow “ leant” to recognize the characteristics of a liveable habitat, become so adept at selecting appropriate habitats that the qualities would be quickly per- ceived, then appraisal would become more automatic. Thus, while looking for a place to settle one could also remain alert for unexpected dangers lurking in the bushes. We are fortunate that the human mind has evolved with the ability to make complex decisions such as selection of habitat with a minimum of mental effort. Throughout the process of evolution, those that do it best are the ones who survive. Role o f Emotional Responses In addition to being informed by our thoughts we are also informed by emotions and feelings. When we feel hungry or thirsty, we eat and drink, when we feel pain, i.e., the water is too hot!-we quickly withdraw our hand. We do not have to think-emotions and feelings are non-cognitive ways of becoming aware. In the evolution of primitive humans, emotional responses became connected with distinct types of behavior. If success in any activity were rewarded with positive emotional responses-joy, pleasure, “ good feel- ings” - it would encourage the individual to repeat the activity whether it  Plants and the Individual 247 would be selecting a safe habitat, or fun activities-eating, drinking, or sex. Negative emotional responses, such as fear, would discourage repetiticm of the behavior. If it does not feel good you do not do it again. If successful selection of habitat engendered pleasant feelings then one would learn to select an environment because it “ felt” good. The reinforcement and reward gained from positive feelings would favor quick intuitive re- sponses rather than slower, more deliberately thought out, responses. In the initial assessment a favorable setting would “ feel” good and an unfavorable setting would not “ feel” good. Feeling good about success- fully recognizing danger or positive qualities would reinforce those adap- tive decisions. If the emotional responses were reliable, then it would be much more efficient to utilize these intuitive responses, rather than slower, more conscious processes. One would prefer the adaptive setting because it “ felt” good. TTie place where conscious, deliberate thought is needed is in figuring out what further action to take in a situation, not in making the initial appraisal and evaluation. If the ability to assess a setting intuitively were genetically pro- grammed, then it would not have to be learned anew by each person. One would be bom with these abilities; much as we are bom with physiological information which establishes norms of heart rate of 72 beats per minute, or body temperature of 98.6“ F. However, the underlying ability to assess an environment is not as inflexible as normal heartbeat Though the genetic component is fixed, its expressicm is mediated by cultural overlay. Iimer-city youngsters were terrified when invited to accompany me into a woodland setting at the Morton Arboretum which for regular visitors is a highly favored spot In a reverse situation, I could well be afraid of the inner city “ turf” which serves as the familiar everyday play area for the same city kids.“* For each of us, cultural experience determines the degree to which the genetic component may be expressed. Both are at work when we look at a setting and intuitively come to know whether we like it or n o t From this view we can understand the basis for landscape preference which has been measured by psychologists^ and geographers^ over the past twenty years. Not only is vegetation itself preferred, but the ways in which it is arranged also creates a hierarchy of preference. An open forest is favored over one with thick undergrowth, the presence of a path or opening on which we could enter and explore the setting also rates high in preference. A highly preferred place is at the edge of a woods where one can peek out to see what might be approaching (prospect) yet at the same time be hidden from the view of those outside the forest (refuge). This would be a very safe place for our primitive ancestors. Geographer Jay 248 People-Plant Relationships: Setting Research Priorities Appleton^ has developed this concept into his prospect/refuge theory of landscape preference. Over the years researchers have found a number of these dimensions which predict preference. Each can be interjected as a cue to the information content of the scene. It is not solely the presence of vegetation but the potential to gain information from the setting that in- fluences preference. The researchers conclude that humans, to operate effectively, need to be able to read the cues in whatever setting is irmnediately at hand. They must be able to infer what is likely to happen and the prospects for continued ability to make sense of it. The remarkably similar results of preference tests across cultures leads researchers to see that an underlying biological component is involved. Though its expression may be affected by culture, the motivation and underlying mechanism seems to be constant. This is not to say that all people will prefer precisely the same setting: in determining which land- scapes people prefer, there appears ample room for cultural influences as well as for the echoes of early human experience. It is interesting to note that when questioned, people are not able to explain their reasons for preferred settings. The choice comes not from conscious thought but from an intuitive or “ gut” feeling that occurs before thought. Landscape o f Savanna Since our humanoid predecessors are believed to have originated in the savaimas of Africa, Gordon Orians^ has studied that biome to determine which of its characteristics might have offered the best opportunities for survival. Savanna is an open landscape of scattered trees with grasses and shrubs between. Sources of food are available for both people and grazing animals. The open landscape affords distant views for safety and also allows one to see what is in the neighborhood. The savanna offered what was needed: “nutritious food that is relatively easy to obtain; trees that offer protection from sun and can be climbed to avoid predators; loig, unimpeded views; frequent changes in elevation to allow us to orient in space. Water as a resource is relatively scarce and unpredictably distributed on African savannas. However, tree shape can be an indicator of its presence. Gordon Orians has studied tree types in African savannas, measuring their characteristics. Using Acacia tortilis as the example, he finds that the shape of the tree will vary with the availability of moisture. “ In high quality habitat, this acacia has the quintessential savaima look-a spreading multi-layered canopy and a trunk that branches close to the ground, an  Plants and the Individual 249 umbrella shape. In wetter, overly moist savannas, the species has a canopy that is taller than it is broad with high trunk, while in dry savanna A. tortilis is dense and shrubby looking.” ^® A savanna with broad shaped trees branched low to the ground would indicate a habitat with proper amount of moisture. Becoming observant of the “ look” of the savanna and preferring tree shapes which indicated moisture availability would have been advanta- geous for the primitive humans who roamed the area. This was a survi- vor’s landscape, and the ability to quickly recognize it would have been a powerful asset. K the inhabitants of the savanna did use the appearance of the landscape to aid in assessing its potential as a survival habitat, they might have developed an innate preference for the distinguishing characteristics of that biome’s landscape. Researchers have found that Americans prefer park-like settings with a ground cover of grass, no tangled underbrush, and a open wide spacing of mature trees.* *’*2 The preferred typical park setting might be characterized as a savaima. Anthropologists sometimes refer to savanna as “parkland.” Further confirmation of continuing savanna preference is found in the results of a study by John D. Balling, psychologist with John Falk, an ecologist (1982).*^ Participants in this study included a Iffoad spectrum of ages-third graders, sixth graders, college students, adults, senior citizens and professional foresters-who lived in an East coast area characterized by temperate deciduous forest. Each group was shown slides depicting five different biomes: tropical rain forest, temperate deciduous forest, coniferous forest, savanna and desert, and were asked to rate the slides in terms of how much they would like to live in or visit a similar area. The third and sixth graders (8 and 11 years old) showed significant preference for savaima over other biomes. Beyond that age, however, familiar natural environments were preferred equally with savanna environments. Since none of the youngsters had ever been in a savanna, the authors conclude that they were expressing a preference for savanna that is innate rather than learned. Only after they are older and have an opportunity to experience and become f^amiliar with other environments do they begin to exhibit more diversity in selecting a preferred biome. The researchers state that the preferences of the younger participants indicate that “humans have an innate preference for savanna-like settings that arise from their long evolutionary history on the savannas of East Africa.” Children are bom with the preference for savanna; only after they expand their knowl- edge base through conscious experience of other landscape types do they express more diverse preferences. They are bora with a preference for 250 People-Plant Relationships: Setting Research Priorities landscape of the savanna already encoded in their genes. In two subse- quent unpublished studies, Balling and Falk ran the same tests on popula- tions in Nigeria and India. The results strongly corroborated the findings of the U.S. study; youngsters strongly preferred savaima while older popu- lations had a wider range of preference. This thought is echoed by Richard Leakey, son of famed African an- thropologists Mary and Louis Leakey, who, when asked why Africa has so profound an effect on people, replied. Genetic m em ory... the vast majority of people who come here feel something they feel nowhere else. It is not the wildlife, it is the place. If, as I believe, it is a memory, almost a familiarity, it is very primi- tive. It is the capacity homing pigeons have, salmon have, to recog- nize, to go back. You feel it’s home. It feels right to be here.^^ Gordon Orians and Judith Heerwagen are studying preferences for tree shapes by residents from Seattle, Argentina and Australia. Initial results indicate that all three groups rated as most attractive those trees with moderately dense canopies and multiple hunks which originate near the ground. Trees with high trunks and either skinny or very dense canopies are judged as less attractive. The trees selected as attractive correlate with the shape of Acacia tortilis growing in adequately moist soils. The kinds of trees and shmbs we select for our gardens might reflect innate preferences for tree shapes. Gordon Orians has studied the woody plants used in Japan where the art of making gardens is an old one. Since few flowers are utilized, the main appeal comes from the shapes and arrangements of non-flowering plants, trees and shrubs. He has looked for evidence that the Japanese might have been in- fluenced by innate preferences for tree shapes of the African savanna. He notes that among species selected, maples, Acer, are used with great fre- quency. Wild species of maples chosen for garden use tend to be broader than they are high, with shorter trunks, and smaller more deeply divided leaves than the species not chosen. In gardens, the maples generally are not pnmed, but allowed to achieve their natural shapes which are charac- teristic of the savanna trees. In selection of oaks, Quercus, evergreen species with smaller leaves were chosen over large leaved deciduous spe- cies. In Japan no conifer achieves a spreading character in its native habitat except for the Red Pine, which, in windswept locations, develops a lay- ered, more horizontal form. The shapes of conifers in Japanese gardens are highly controlled by rigorous pruning, creating evergreens with a distinct- ly layered aspect, encouraging the effect of a canopy broader than tall with  Plants and the Individual 251 trunks that branch close to the ground, all echoing characteristics of savan- na trees. The horizontal effect is encouraged by supporting long, low spreading branches to permit an unusual extension of growth. At the Morton Arboretum one can find that preferred shape in crabap- ples and hawthorns. When Tony Tyznik, the landscape architect, selects and prunes specimens of these trees, their savannah shape becomes more evident. For Mr. Tyznik this shape is aesthetically satisfying. Time Frames o f Decisions Nature’s Cues While ionising day to day affairs, concentrating on the work at hand, it would be important for primitive humans to recognize cues that portend events of great importance. If the cue indicates danger or a sudden change, an immediate response is needed. This would be much the same as the sound of a fire alarm drawing attention to a potentially imminent threat. The response to such a cue must take place quickly, overriding any preoc- cupation of the moment. From an evolutionarily adaptive viewpoint, alarm cues would be most effective if they aroused a strong emotional response in those who perceive them. The added power of emotion would draw attention even more strongly to the cue. Cues which portend a change in weather would be particularly impor- tant, in that they may indicate a change for which one would have to prepare. Some cues call for immediate action; clouds, wind or temperature changes, would fall in this classification. They could mean that one might have to move to a more sheltered location to find protection from the impending storm. Other cues portend changes which occur more slowly and are effective over a longer period of time, would not be of such immediacy as to require instantaneous , action. Indicators foretelling the change of season would have been of great importance. They would signal the need for a longer preparation period than is allowed for a passing thunder shower; they may affect behavior for several months as in moving from summer pasture to protective winter habitat. The change from summer to fall to winter is heralded by a variety of signals-a difference in the quality of light as the sun’s trajectory moves from overhead in summer to lower on the horizon with the approach of winter. Changes in foliage color in fall would be an important indication that preparations for surviving the long winter should be made. The environmental alarm bells set off behaviors in our primitive ancestors that were adaptive, and helped them to survive. The alarms still sound within us today. We are sensitive to the onset of 252 People-Plant Relationships: Setting Research Priorities afternoon and night. Sunrise and sunsets remain deeply fascinating to us. For an animal with poor night vision, such signals would be cues to seek shelter from the coming darkness, to prepare for a new day. We are end- lessly enthralled with the shapes of clouds in the sky: poets and painters use their skill to portray them to us. But our ancient ancestors also read the clouds for information about weather, water and shade. In Spring, trees start to turn green, grass grows, flowers bloom and we are drawn to witness life’s renewal. In autunm, millions of us head for the countryside or mountains to view the spectacle of leaves turning orange, red, yellow, and purple before falling to the ground. It is almost a homing instinct that we see each fall at the Morton Arboretum. For several weeks attendance increases and, at the peak, cars ride bumper to bumper through the brilliant fall display. Interestingly, most of the visitors could observe the change in color of vegetation near their homes, but they feel a strong need to come to the Arboretum, a “natural” place where they can be immersed in the spectacle with few reminders of the constructed world in which they live. Poets and nature writers have tried to portray the emoticNis hidden in an experience with nature. In William Wordsworth’s The Rainbow, the poet exclaims, “ My heart leaps up when I behold a rainbow in the sky.” *^ The rainbow is in the sky, but the up-leaping heart is in Wordsworth. The visual image is brought inside where it comes to life as personal experi- ence. As Wordsworth experienced the rainbow, Annie Dillard in Pilgrim at Tinker Creek tells of a cedar transfigured, “ the tree with lights in it.” ** She is awestruck by the sight and tries to fmd words to describe feelings that arise from her experience with nature. Other signals that were adaptive for primitive humans still call to us today. Fire, contained in a fireplace or within the confines of a camp circle, is comforting and rewarding. One can stare endlessly into the flames, hypnotized by the sounds and the array of brilliant flickering patterns. The same fire, uncontained, consuming buildings, forests, fields is a threat-but none-the-less a strong source of fascination. Early humans would have had to be quickly aware of large or fierce animals which could easily be life threatening. One would either have to climb to safety, prepare to capture and kill the animal, or be killed. Today hunters reenact primitive rituals and others of us flock to zoos and safari parks in response to a complex relationship, our fascination with the animals with whom we have always shared the earth. Our love of flowers could well be of ancient origin. In an otherwise green and teown world, flowers could be colorful indicators of future sources of food. Hybridization of flowers often turns to more striking  Plañís and the Individual 253 forms and colors-doubles, large blooms, bicolor and multicolored-all of which make the flower more easily apprehended. Flowers have held a place of importance for a long time. Excavatiwi of Neanderthal burial sites in Iraq reveals an abundance of pollen grains in each grave, a sign that flowers were part of that final act.'^ Why this digression into evolution and the deeply rooted origin of contemjwrary landscape preferences? Stephen Kaplan comments, “ While the survival requirements of humans differ in many ways from those of our ancestors, in many respects the story has not changed dramatically. One must still negotiate the physical environment, assess lurking threats and dangers, and concern oneself with finding one’s way back. Nor have humans ceased to be information-based animals, continuously struggling to make sense of their surroundings and exploring new adventures. We at this symposium are well aware of the strong positive effects of plants on human well-being. From this evolutionary perspective we can see that these responses are not superficial or of the mcmient, but rather signal the presence within each of us of a genetically continuing connec- tion with green nature, from which our species learned how to survive. We must become more consciously aware of these encoded meanings of green nature and be reminded of that important green coimection. When you stroll through gardens, grow plants, enjoy a walk in a park or forest, know and heed the ancient guardian within each of us that continues to guide us in directions that are beneficial for humanity now and in the future. REFERENCES 1. Stephen Kaplan, Environmental Preference in a Knowledge-seeking, Knowledge-using Organism, The Adopted Mind: Evolutionary Psychology and Generation o f Culture, J.H. Barkow & J. Tooby (Eds.), Oxford (In press). 2. Richard H. Wagner, Environment and Man, Norton, New York, 1971, p. 5. 3. Ibid. 4. Charles. A. Lewis, Nature City: Translating the Natural Environment Into Urban Lmgmg&, Morton Arboretum Quarterly, 11(2) 17-22, 1975. 5. Stephen Kaplan, Environmental Preference in a Knowledge-seeking, Knowledge-using Ch^ganism, The Adapted Mind: Evolutionary Psychology and Generation o f Culture, J.H. Barkow & J. Tooby (Eds.), Oxford (In press). 6. Roger Ulrich, Robert F. Simons, Barbara D. Losito, Evelyn Florito, Mark A. Miles, & Michael Zelson, Stress Recovery During Exposure to Natural and Ur- ban Environments, Journal o f Environmental Psychology, 11, p. 201-230,1991. 7. Jay Appleton, The Experience o f Landscape, John Wley, New York, 1986. 8. Gordon Orians and Heidi Heerwegen, Evolved Responses to Landscapes, in The Adapted Mind: Evolutionary Psychology and Generation o f Culture, J. Barkow, L. Cosmides, & J. Tooby (eds), Oxford, (in press). 254 People-Plant Relationships: Setting Research Priorities 9. Ibid. 10. Ibid. 11. Herbert W. Schroeder & Thomas L. Green, Public Preferences for Tree Density in Municipal Parks, Journal of Arboriculture, ll(9):272-277, September 1985. 12. Rachel Kaplan, Dominant and Variable Values in Environmental Prefer- ence, in Environmental Preference and Landscape Preference^ A.S. Devlin & S.L. Taylor (eds.). 13. John D. Balling & John H. Falk, Development for Msual Preferences and Natural Enwixoxwa&xiU Environment and Behavior^ 14(l):5-28, 1981. 14. Aaron Latham, To a Stranger, Africa Feels Like Home, The New York Times, November 10,1991. 15. Gordon Orians, Habitat Selection: General Theory and Application to Hu- man Social behavior, in J.S. Lockard (ed) The Evolution of Human Social Behav- ior, Chicago, Elsevier, 1980. 16. Gordon Orians, An Ecological and Evolutionary Approach to Landscape Aesthetics, in E.C. Penning-Roswell and D. Lowenthal (eds) Landscape Meaning and Values, Allen and Unwin, London, 1986. 17. William Wordsworth, The Rainbow, The Oxford Book of English Verse, Quiller-Couch (ed), Oxford University Press, New York, 1940. 18. Annie Dillard, Pilgrim at Tinker Creek, Harpers, New York, 1974, p. 33. 19. Rose S. Solecki, Shanadar FV, A Neanderthal Burial Site in Northern Iraq, Science, 190,28: 880-881,1975. 20. Stephen Kaplan, Environmental Preference in a Knowledge-seeking, Knowledge-using Organism, The Adapted Mind: Evolutionary Psychology and Generation o f Culture, J.H. Barkow, L. Cosmides, & J. Tooby (eds.), Oxford, (In press).