2. Development of Landscape Preference Theories
2.1. The Need for Survival
Survival is the most basic human need. The Prospect-Refuge Theory developed by Appleton 
, a British geographer, reveals that humans have a tendency to prefer particular conditions of landscapes/views and vantage points known as prospects (unobstructed open visual access) and refuges (enclosed spaces and areas of concealment). Examples of this include savannah, open forest, and river and lake landscapes. The theory of Habitat Selection proposed by Orians 
assumes that as humans evolved from the African savannah, they genetically developed a preference for habitats or environments that offer advantages for survival. To date, people living in different environmental contexts seem to have a universal preference for this type of natural landscape over any other type of landscape 
. They tend to produce positive psychological responses to potentially suitable habitats and negative responses to those not suitable to live in 
. Similarly, E.O. Wilson 
, an American sociobiologist, believed that humans, in the lengthy process of biological evolution, developed a genetic preference for natural environments that can improve their chances of survival by avoiding danger and acquiring food. This became known as the Biophilia Hypothesis. It has been found from previous studies that landscape elements can influence landscape preferences and that human preferences for landscape elements that contribute to survival are more pronounced 
. Dai et al. 
also argued that the preference for landscape elements has a strong correlation with psychological effects. For example, natural landscapes such as flowing water, abundant vegetation, and a blue sky will alleviate people’s negative emotions. Therefore, prioritizing these landscape elements in landscape design can facilitate landscape architecture projects.
2.2. The Need for Affection
Humans are also significantly influenced by emotions. Research on the brain demonstrates that “emotion is a primitive system” that allows humans to quickly respond, despite having little information about conditions that matter to survival and well-being 
. Yi-Fu Tuan, a Chinese-American geographer, developed the concept of “Topophilia” in 1974, from the perspective of human geography. Although Tuan did not declare his research field as belonging to LP, the concept of topophilia enriched the methods of studying landscape from the viewpoint of human geography.
Ulrich was an architecture professor who sought to explain “the psychological basis of affective responses to landscapes” by putting forward a psychological model based on the psycho-evolutionary theory 
. He concluded that affects are regarded as “products of thought”. He also concluded that if this viewpoint is adopted to explain “aesthetic and affective responses to the natural environment”, the general perspective can be interpreted in the following way: “an observer’s affects are post-cognitive phenomena resulting from a process of cognitive evaluation or appraisal of a scene” 
. Later, Ulrich 
summarized “aesthetic, emotional and physiological response to visual landscapes” and highlighted “aesthetic preferences for views containing trees and other vegetation”. He suggested that aesthetic preference is critical to the “thoughts, conscious experience and behavior” of a landscape observer.
2.3. The Need for Cognition
Rachel Kaplan is a professor of environmental psychology whose research interest mainly focuses on environmental preference, the role of the surrounding natural environment, and the participation of its citizens 
. Stephen Kaplan, a professor of Psychology as well as Computer Science and Engineering, specializes in the field of “cognitive approaches to human-environment compatibility, psychological properties of natural environments, and evolutionary factors in human information processing” 
. In the 1970s, Rachel and Stephen Kaplan began to explore the relationship between the natural environment and human psychological characteristics. They pointed out that preference is directly associated with people’s psychological responses, and also people’s experiences, emotions, evolution, and other factors closely related to the level of LP 
. The Information Processing Theory proposed by Rachel and Stephen Kaplan 
is considered one of the most influential psychological theories 
. The theory advocates that the need for understanding and exploring a landscape was critical for human evolution. On this basis, Kaplans created a preference matrix with four informative elements that influence LP: coherence (immediate understanding), complexity (immediate exploration), legibility (inferential comprehension), and mystery (inferential exploration) 
Finally, human cognition, excluding biological instinctive responses, may be influenced by factors such as age, experience, and culture. Van den Berg et al. 
found that an individual’s environmental preference is related to his or her ability to derive restorative benefits from the environment. Ulrich 
and Kaplan 
put forward the Stress Reduction and Attention Restoration theories, respectively, both of which explain the restorative effects of natural environments from a psychological mechanism perspective. Based on the Psycho-Evolutionary Theory, the Stress Reduction Theory believes that people produce “positively toned feelings” when observing natural environments 
. Some scholars found that when individuals are under stress or anxiety, the level of sophistication of their preferences will decrease 
. The Attention Restoration Theory is established around the concept of “Directed Attention” 
derived from modern neuroscience, and focuses on the potential cognitive benefits of the interactions between humans and natural environments 
. Research on environmental psychology indicates that experiences of direct perception (i.e., visual sense) of natural scenes and elements, especially vegetation and water features, can have a positive impact on individuals by enhancing stress reduction 
and promoting spiritual recovery from fatigue 
. Figure 1
below presents the classification of LP theories.
Figure 1. Theories of Landscape Preference can be divided into three categories: (1) the need for survival, (2) the need for affection, and (3) the need for cognition.
3. A Theoretical Model of Landscape Preference Based on Cognitive Neuroscience
In view of the theories mentioned above, researchers have developed a conceptual framework to describe the physiological and psychological process of LP from the perspective of Maslow’s Hierarchy of Needs Theory (Figure 2). The discussion will be carried out from two primary aspects: first the psychological process, and second, the evaluation mechanism. The framework is only a preliminary exploration of the reasons behind LP, and further research will be conducted based on this framework.
Figure 2. Drawing on Maslow’s hierarchy of needs theory, the evaluation of landscape preference is divided into five parts: survival, security, love and belonging, esteem, and self-actualization and self-transcendence needs, which correspond to the theories related to landscape preference proposed by previous scholars.
3.1. The Neural Basis of Landscape Preference Evaluation
The human brain consists of approximately 100 billion neurons which perform multiple tasks, and to a certain extent, “our thoughts, feelings, and behaviors depend on neural communication”, that is, “the electrochemical action of neurons” 
. Neurons are the fundamental cells of the nervous system that “communicate with one another to perform information-processing tasks” 
. They are responsible for receiving, evaluating, and transmitting information, and their “electrical and chemical activities” are the fundamental start for all behavior, thought, and emotion” 
. According to the deduction of Ramón y Cajal and other researchers of his time, neurons work in a pattern that they “receive information”, then “make a ‘decision’ about it following some relatively simple rules” before finally sending the electrical signals to other neurons “by changes in their activity levels” 
The thalamus is the part of the brain that receives all incoming sensory information, with the exception of smell, passing on messages to the cerebral cortex 
. The cerebral cortex is the highest level of the brain, and it is responsible for the most complex functions in cognition, emotion, movement, and thought 
. It has two symmetric hemispheres, each of which is composed of “large sheets of (mostly) layered neurons” 
. After the cortex finishes processing information, a signal will be sent to the amygdala 
. Norman Geschwind 
found that the sensory information processed by other areas of the brain must work together with the amygdala in order to properly associate the information with “affective and motivational labels”. The amygdala is considered to be a part of the limbic system, and plays a critical role in generating emotion and memory as well as making evaluations 
3.2. The Nerve Conduction Path of Environmental Information
A psychologist, LeDoux 
, mapped the pathways through which stimulus information travels around the brain. He discovered that there are two amygdala pathways in the brain working simultaneously to transmit information: the “fast pathway” goes from the thalamus to the amygdala, and the “slow pathway” goes from the thalamus to the cortex before reaching the amygdala. Remarkably, the fast pathway is similar to the process of cognition, whereas the slow pathway is similar to the process of perception. Thus, while the cortex is processing the information to analyze the identity and significance of the stimulus comprehensively, the amygdala is conducting very quick and simple decision-making based on the information coming directly from the thalamus. In other words, stimulus information is passed on synchronously to the amygdala which implements “a quick appraisal of the stimulus’s goodness or badness” and the cortex which performs “a slower and more comprehensive analysis of the stimulus” 
. Sometimes, the amygdala may evoke an emotional experience first, followed by the cortex suppressing that emotion 
Aesthetics is a complex psychological process 
, involving multiple sub-processes such as perception, affection, memory, evaluation, and judgment 
. During the aesthetic process, the observer will first visually analyze environmental stimuli and extract simple and basic visual elements 
. Then, the brain will perform selective aesthetic reproduction on the received environmental information, and ultimately make aesthetic judgments, thereby generating an aesthetic experience 
. The process of aesthetic reproduction is always accompanied by changes in emotions 
. Emotions affect the aesthetic experience and vice versa. When the subject is undergoing an aesthetic experience, his or her emotional state plays an essential role in aesthetic activities, arousing the individual’s specific emotions or affective reactions in viewing aesthetic objects. Hence, the subject’s emotional state cannot be ignored when discussing aesthetic activities. Many previous studies have also demonstrated that emotional states are closely related to landscape preferences. For example, people with positive moods prefer open landscapes, while people with negative moods prefer element-rich landscapes 
3.3. Evaluation Based on Maslow’s Hierarchy of Needs
In normal conditions, the appraisal happens quickly and unconsciously. However, it can sometimes be “slow, deliberate and conscious” in terms of “what is happening” 
. A major characteristic of humans is that they are animals of desire with satisfaction lasting only a short period of time 
. The presence of a motive or desire leads to people’s actions or responses, and satisfaction can be obtained through achieving goals 
. Therefore, researchers hold that latent desire is the reason for the existence of human LP. Such desire can be discussed in conjunction with Maslow’s Hierarchy of Needs (Figure 3
Figure 3. Maslow believed that people have six different levels of needs latent in them, and the urgency of the various needs expressed at different times is different.
3.3.1. Physiological Needs
Several theories, including the Biophilia Hypothesis and the Habitat Selection Theory, propose that there is a biological basis for landscape preference 
. These include needs such as food, water, sleep, and sex, the most basic needs for human beings. Only after these basic needs are met will people pursue higher-level needs.
3.3.2. Safety Needs
Safety appears after physiological needs are met. Like physiological needs, safety needs also belong to the lower levels of human needs. The normal operation of the organism entails a relatively safe environment, including personal, labor, occupational, life stability, and property safety, etc. This is consistent with the Prospect-Refuge Theory, Information Processing Theory, Stress Reduction Theory, and Attention Restoration Theory.
3.3.3. Love and Belonging Needs
When the two needs mentioned above are satisfied, the needs for love and belonging, which are also the social attributes, will emerge. This level of needs includes two aspects. One is to fit into a group and establish a harmonious relationship with it. The other is to receive love from others. This is also reflected in Topophilia.
3.3.4. Esteem Needs
These are among the higher-level needs of human beings, and they are centered on self-esteem and gaining respect from others. However, when these needs are not met, it can cause a person to lose confidence and create feelings of incompetence, such as low self-esteem and vulnerability 
. Therefore, the design of public spaces, semi-public spaces, and private spaces are closely associated with these needs.
3.3.5. Self-Actualization Needs
Being regarded as growth needs, they concern the need of realizing one’s dreams and aspirations to the greatest extent, and giving full play to one’s potential. In this way, they are the driving force that enables people to realize their desires and values 
. Self-actualization needs will not arise until the first four levels of needs are met. Self-actualized people are better able to perceive the natural world. They can understand the interdependence of humans and other creatures, and make connections with entities beyond themselves. “Therapeutic gardens” are closely associated with these needs.
3.3.6. Self-Transcendence Needs
Maslow pointed out that some people do manage to go beyond the level of self-actualization 
, so he introduced the concept of self-transcendence needs as the highest of the six levels of needs. Ecological aesthetics and participatory landscapes are examples of self-transcendence needs relevant to the LP theories.