Psychology of natural scenes

Goals

Goals of this research include:

1. Review and test relevant theories about the possible influence of natural scenes on psychological stress and/or mood
2. Identification and collation of freely available nature images for current and future research studies
3. Develop a means of electronically presenting images and recording participant responses, to readily allow for world-wide experimental research
4. Identification of the psychological effects of viewing, being in, and interacting with nature
5. Development of digitally restorative environments

Providing digitally restorative has many implications for human well-being, particularly given increasing urbanisation and dwindling access to natural environments.

Theories

Why is nature beneficial? ^[1]

Most theories draw on the biophilia hypothesis and evolutionary theory, more broadly, to explain the human health benefits of exposure to nature.

Attention restoration theory is more cognitive, focusing on how natural environments engage involuntary attention, allowing the recovery of a fatigued directed attention system. Stress reduction theory is more physiological and emotional.

Attention Restoration Theory

1. "Kaplan and Kaplan's (1989) attention restoration theory (ART) explains the positive, restorative effects of green spaces on the overuse of directed attention (= mental fatigue). According to the ART an environment has restorative potential (qualities) if four components, being away, fascination (effortless attention), coherence (coherent physical environment of sufficient scope) and compatability (match between person purposes and environment), are available in the human-environment interaction. Based on this theory restorative environments contribute to restoration by recovering directed attention and by clarifying and restructuring thoughts." (de Vries, ClaBen, Eigenheer-Hug, Korpela, Maas, Mitchell, & Schantz, 2014, p. 227)
2. The theory of two types of attention (involuntary and voluntary) goes back to the work of James (1892). Voluntary (or directed) attention requires effort, and involuntary attention (or fascination) requires no effort (cited in Kaplan, 1995). See Attention Restoration Theory (Wikipedia).

Kaplan (1984) Kaplan, R. (1984). Impact of urban nature: A theoretical analysis. Urban Ecology, 8, 189-197.

Kaplan, 1995

1. James didn't address the potential that direction attention could be susceptible to fatigue.
2. Directed attention requires effort, is under often under voluntary control, inhibits attention to distraction, helps to achieve focus.
3. Sustained mental effort leads to fatigue of directed attention
   1. This can be explained in terms of evolution: In the past, being alert to ones surroundings was probably more important than being focused on one thing for a particularly long period of time. Also in times of the less-evolved human, things like caves, blood, danger and wild animals which were essential to survival were innately interesting. Today these things remain inately interesting, but they are less essential to survival. Instead, more tedious tasks are more important to every day life, thus one must resist being distracted by that which is more innately interesting.
4. For early humans, what was 'interesting' and what was 'important' were synonymous. These days, it's not the case, where people have to pay attention to uninteresting, repetitive work (such as work in a factory)
5. Directed attention is particularly important in:
   1. problem solving, where habitual, learned responses are not appropriate
   2. inhibiting instinctual 'flee' response, because often these days, fleeing is not appropriate/beneficial (e.g. in a stressful job interview.
   3. perceiving and understanding things which are not inherently interesting
   4. certain important jobs like air traffic control, where one must focus on that which is not intrinsically interesting and there are many inherently interesting things around.
   5. Inhibiting responses allows us time to think about our best possible response. It also allows us to act reasonably and responsibly in social situations by following norms rather than following impulse
   6. In the modern world, job have become more and more specialized. Decreased variability possibly makes a job less inherently interesting, thus using more directed attention.
   7. Thus, directed attention is a key to being successful in modern life

The restorative process, Kaplan, '95

1. Because directed attention is susceptible to fatigue, it needs time to rest so it can again work effectively.
2. Sleep is one way to gain this rest; but sleep is often not appropriate in given situations, so an alternative is needed
3. involuntary attention, requiring no effort, allows directed attention to rest. It is essential for, but in itself not sufficient to the rest and recovery of directed attention.
   1. being in a novel area where one is surrounded by things which capture involuntary attention (which Kaplan calls 'fascination') is beneficial, but so is changing the direction of ones gaze, or seeing an old environment in a novel way.
   2. a restorative environment involves a sumptuous and coherent set of experiences which are percieved as another 'world', rather than a series of unrelated perceptions.
   3. natural settings like forests, streams, the ocean, and mountains meet the above conditions.
   4. nature provides people with sources of 'soft' (i.e. undramatic) fascination, such as the swaying of trees in the wind, sunsets, or foot prints on the beach.
   5. People are also attracted to environments because of the certain activities that can be performed in that environment i.e. fishing in a lake, hunting in a forest, planting in a garden bed.

Kaplan (1995) on stress

1. It is generally accepted that stress is a reaction to a potentially negative situation. Stress is triggered by a sense of physical or psychological harm (either impeding or current) or by a sense of possesing inadequate resources. Due to the diversity of situations which prompt stress reactions, it is possible that it is actually depletion of some underlying resource with causes stress.
2. The requirements of some underlying resource is that it
   1. play a pivotal role in a persons effective functioning
   2. is vulnerable to depletion
3. directed attention fits these requirements because, as mentioned above, it effects functioning through inhibition and important attention to uninteresting but essential tasks.In support of this theory, Hancock and Warms (1989) cited in Kaplan suggest that lack of attentional resources can lead to stress.

Kaplan (1989) on stress

1. stress and mental fatigue are distinct constructs, where stress is a preparatory response, and mental fatigue is an outcome.

Kaplan 1989 on restoration

1. People describe 'escape' as a way to find relief from directed attention. Escape means an absence of that which is causing the fatigue and implied (1)'get away' from what is causing fatigue (i.e. physically remove yourself) (2)'put it aside' (i.e. move it) (3)mentally focusing on something else. Under these conditions, however, one might end up in a closed, empty room; so there must be more to 'restorativeness' than simply 'escape' (p. 183)

Key terms by William James, 1982 (from Kaplan & Kaplan, 1989)

1. Voluntary and attention
2. Involuntary attention (that which is exciting)
3. Inhibition
4. Kaplan & Kaplan deducted that fatigue comes from resisting exciting stimuli whilst trying to concentrate on less exciting things (i.e. using voluntary or 'directed' attention)

Stress Reduction Theory

1. "Compared to the ART, which is focused on cognitive processes, Ulrich (1983), Ulrich et al.'s (1991) stress reduction theory (SRT) is more focused on emotional and physiological processes. The SRT is based on the belief that viewing or visiting natural environments after a stress situation rapidly promotes physiological recovery and relaxation (Ulrich, 1983)." (de Vries, ClaBen, Eigenheer-Hug, Korpela, Maas, Mitchell, & Schantz, 2014, p. 227)

Processing fluency theory

1. Joye (2009)
2. Processing fluency theory of aesthetic pleasure (Wikipedia)

Effects

Frumkin (2001)

A useful review of the research literature about the effects of nature on human health was provided by Frumkin (2001).

Bowler et al. (2010) meta-analysis

1. Bowler, Buyung-Ali, Knight and Pullin (2010) conducted a systematic review of 25 studies about the benefits to health of exposure to natural environments (including public parks, green university campuses, and synthetic environments, such as indoor and outdoor built environments). The most common outcome measures were self-reported emotions. Based on meta-analysis, "there was some evidence of a positive benefit of a walk or run in a natural environment in comparison to a synthetic environment. There was also some support for greater attention after exposure to a natural environment but not after adjusting effect sizes for pretest differences. Meta-analysis of data on blood pressure and cortisol concentrations found less evidence of a consistent difference between environments across studies." (p. 1)
2. Most studies investigated the effects of active participation in natural environments, particularly walking or running, but also including wilderness backpacking, gardening, passive/sedentary activity or a mixture of activities (p. 4).
3. Bowler et al. (2010) concluded that "the studies are suggestive that natural environments may have direct and positive impacts on well-being, but support the need for investment in further research on this question to understand the general significance for public health" (p. 1).

Table 1.
Pooled Effect Sizes (Hedges' g) and 95% CIs Comparing Before and After Activity in the Natural Environment (adapted from Bowler et al., 2010).

Outcome	Effect size	95% CI	No. studies
Attention	0.23	(-0.30, 0.76)	3
Energy	0.76	(0.30, 1.22)	5
Anxiety	0.52	(0.25, 0.79)	6
Tranquillity	0.07	(-0.42, 0.55)	7
Anger	0.35	(0.07, 0.64)	6
Fatigue	0.76	(0.41, 1.11)	4
Sadness	0.66	(0.16, 1.16)	3
Systolic BP	0.02	(-0.42, 0.38)	4
Diastolic BP	0.32	(-0.18, 0.82)	3
Cortisol	0.57	(-0.43, 1.57)	4

Note. The sign of the effect size reflects the benefit on health (positive effects indicate greater attention, energy and tranquillity but lower values for the other outcomes). Number of studies reflects the number of studies for which there was data available to calculate this effect size (i.e with pretest data).

Key researchers

Kaplan

The Kaplans (along with Ulrich) have been two of the main early researchers of the effects of exposure to natural views.

Kaplan & Kaplan '89

• One way people categories a scene is by how much human influence is seen in the image (p. 28), or of perceptions of 'natural' versus 'built' (p.30)
• Human influence is a prominent dimension by which people categories images (p.31) and is perceived by cues such rubbish, abandoned cars houses and bridges (p.29). Human influence does not necessarily mean buildings or additions to a scene, it can be seen through things like clear-cutting (p.44)
• Peoples 'preferences' can very unique, and this can be seen in their choices of posters and images which they surround themselves with (posters, photos, desktop images, screen savers), but Kaplan & Kaplan suggest (p. 41) that there is also a universal preference, and they aim to elucidate these.
• Across the animal kingdom, suitable and safe habitats are preferred, and this is potentially a characteristic of humans, too (p. 41)
• Majority of studies find that images which show the most obvious signs of human influence are least preferred.
• images can also be clasified in terms of 'affordance' i.e. what the environment has to offer the viewer; what he/she is able to do in this environment (p.32)
• one category of affordance is 'openness', another is spatial definition' (p.32)
• openness is where the sky is a dominant feature in the image, and where the image lacks any other distinct figures (p.32)
• Anderson (1978, cited in Kaplan & Kaplan '89, find article!): Included in the openness category are open and unused landscapes such as meadows, uncultivated fields, wildlife openings
• Spatial definition means having a few natural land marks (e.g. trees) to allow preception of the spacial (eg size & depth) aspects of the scene (p.34). Scenes with high spacial definition are open areas with few landmarks (p.35). Scenes with low spacial definition are very open areas with very little or no landmarks (easier to become lost in), or are the opposite; densely populated, seemingly impenetrable areas (p.35) which would be hard to see/move around in (p.37). Dense ((Woodcock 1982 in Kaplan p47) and 'blocked' (Gallagher 1977 cited in Kaplan p47) were natrual scenes that were less preferred.
• Not all scenes showing human influence were rated poorly, 'small structures in natural settings' was highly preffered, which included 'boardwalk' scenes, where a wooden boardwalk was present in an otherwise entirely natural scene (Miller, 1984 cited in Kaplan). Scenes containing a boat have also been found to be moderately preferred (Hudspeth, 1982, cited in Kaplan)
• Water scenes are often the most preferred (p. 50). Industrial scenes are often least preferred (p50)
• Cultural differences exist (p. 51). Quote from Kaplan (p.51) "Americans looking at Australian landscapes are not likely to understand that trees without leaves are diseased rather than showing seasonal variation, because they are not aware that Australia has no native deciduous trees (Kaplan & Herbert, 1987)"
• The need to explore is an inherent human attribute (p. 51), as such humans will prefer environments in which they can explore (p. 52). Humans experience negative affect, like frustration and aggravation, when experiencing environments which they struggle to comprehend, so easy to understand environments are preferred (p. 51)
• Higher coherence and complexity of the scene predict higher preference. Coherence refers to the organization of sizes, textures and brightness (p. 54). Complexity refers to a scene having a number of different elements (p. 53). A scene that is high on complexity and low on coherence will look messy. One which is high on coherence and low on complexity will be simple, clear, and underwhelming. A scene that is high on both (i.e. one which is high on 'legibility') will be rich and organized (see Table 2.2 p. 54). Complexity (e.g. landmarks) help the memorability of a scene, which increases preference, as a memorable scene will be easier to function/move around in.

Ulrich

Ulrich (along with the Kaplans) have been the key early researchers of the effects of exposure to natural views.

1. Ulrich (1981). Natural versus urban scenes: Some psychophysiological effects. Summary
2. Ulrich (1983). Aesthetic and affective response to natural environment.
3. Ulrich (1984). View through a window may influence recovery from surgery. Classic study of hospital patients and windows with natural settings versus brick walls.
4. Ulrich (1986). Human responses to vegetation and landscapes.
5. Ulrich, Simons, Losito, Fiorito, Miles, and Zelson (1991). Stress recovery during exposure to natural and urban environments.
6. Ulrich (1993).

Hartig

• In a series of experiments comparing cognitive functioning in a group exposed to natural environments versus those exposed to urban environments, Hartig ((1991) cited in Kaplan 1995, find article) found that after exposure to environments, those in the natural group had a higher level of cognitive functioning (as measured by proof reading tasks), compared to those in urban environments. Performance on cognitive tasks is closely linked to directed attention because success on such tasks often involves concentration on tedious tasks. This sugests that exposure natural settings give directed attention time to rest and be more effective when it was needed to complete cognitive task.

Kahn

• Peter Kahn Jr.
• Friedman, B., Freier, N. G., Kahn, P. H. Jnr. (2008). Office window of the future? Field-based analyses of a new use of a large display. International Journal of Human-Computer Studies, 66(6), 452-465, DOI: 10.1016/j.ijhcs.2007.12.005.

Herzog

Herzog 1989

• Aimed to investigate the Kaplans 'informational' approach, which relates to two processes: content and process.
• Images can be interpreted in terms of their general and specific contents, where the general content refers to what one assumes they can do in the environment, and specific contents refer to the physical aspects withing the image, such as trees, water etc.
• Processes refer to 'understanding' and 'exploration', which include vary depending on amounts of: nature, typicality, mystery, legibility, complexity, coherence, refuge, age and spaciousness all contribute to the preference for natural and urban scenes.
  • Spaciousness: How much room there is to wander in a scene, how far away is the farthest point
  • Refuge: to be hidden, the chance to see without being seen
  • Coherence: how well structured is the scene
  • Complexity: how many elements are in the scene
  • Mystery: finding out more if you were to walk deeper into the scene
  • Typicality: How representative is the image of the category which it belongs to
  • Nature: how much 'foliage' is there in the scene
  • Age: how old do the elements in the image seem to be
• A sense of familiarity to a place would aid understanding, but too much familiarity would detract from 'mystery'. In this study, 'familiarity' was instead referred to as 'typicality', describing whether or not the image was a good or typical example of the category from which it is a part of. Purcell et al. (2001) found that familiarity had a curvilinear relationship with resorativeness and preference, where the most familiar scenes were those which were moderately preferred and perceived as moderately restorative.
• The above 'processes' were used as predictor variables, and the criterion variable was 'preference' defined as 'how much you like the scene, for whatever reason'
• Pictures were further classified into one of four groups:
  • Older buildings
  • Concealed foreground, where the foreground was mostly (but not entirely) concealed
  • Tended nature, where images exhibited cultivated, well looked after natural elements (such as trimmed hedges)
  • Contemporary buildings
• Tended nature was the highest in preference, and older buildings were the lowest.
• As for processes, the only significant predictors were nature, coherence and mystery. Adding image categories as predictors (i.e. 'tended nature') accounts for no extra variance in preference scores.
• Age as a process did not account for any variance in preference scores, which was interesting considering that older buildings were the least preferred category. This is possibly because the older buildings may have been forgotten for some time hence contained messy, disorganized grounds which needed tending to.
• These findings support the informational model where coherence is an 'understanding' variable and mystery is an 'exploration' variable.
• 'Typicality' was uncorrelated with preference and only had moderate correlations with the other predictors. Participants were possibly overwhelmed by having to make this assessment regarding so many images, so a reversion back to the original term of 'familiarity' is recommended.
• The other five insignificant predictors look to form part of a cluster which may be explained by 'coherence'

Pretty

Pretty et al. (2005)

1. Discusses three types of involvement with nature: viewing, presence, and participation. Each type of involvement appears to facilitate a variety of health and well-being benefits.
   1. Viewing nature, as through a window, or in a painting
   2. Being in the presence of nearby nature, which may be incidental to some other activity, such as walking or cycling to work, reading on a garden seat or talking to friends in a park
   3. Active participation and involvement with nature, such as gardening or farming, trekking or camping, cross-country running or horse-riding
2. found that viewing pleasant urban or rural photographs after exercise led to a greater improvement in self-esteem compared to viewing no photos or unpleasant ones; where 80% of participants experience increased self esteem after viewing pleasant rural images vs 65% of those in the urban pleasant category (which was the same as the no-image control). Other findings included:
   • Viewing unpleasant scenes led to a decrease in self-esteem when the positive effects of exercise were accounted for.
   • Viewing pleasant rural scenes provided an increase in all 6 mood measures, though the increase was not always significant.
   • Viewing pleasant urban scenes had a similar effect, but 5 out of 6 results were significant
   • Significant reductions in depression-dejection (as measured by the POMS) for urban pleasant scenes, no others.
   • More reduction in tension-anxiety for pleasant scenes than for unpleasant ones.

Barton and Pretty (2010) conducted a meta-analysis of green exercise studies.

Korpela

• In 2002 used affective priming effect to test affective associations with natural and urban environments.
• Affective priming effect: Shorter reaction times to target when 'prime-target' pairs are congruent (p637)
• Participants were presented with a series of image-voice combinations which consisted of natural and urban images; and voices conveying either positive or negative affect. After presentation of the stimuli, Participants were asked to identify if the voice was joyful, angry or neutral. Total stimulus lasted for either .45 of a second or 1.45 seconds.
• Results show and interaction between image and tone-of-voice, where participants responded quicker to urban-negative and natural-positive pairs compared to urban-positive and natural-negative pairs.
• This suggests that natural and urban environments produce automatic and rapid affectual responses

Green spaces in natural settings (beach, lake, ocean, park, and forest) predominate among favourite places and are underrepresented among unpleasant places (Korpela, Hartig, Kaiser, & Fuhrer, 2001). Respondents in this study noted that their favourite places elicited feelings of relaxation, happiness, and excitement.

Korpela, K., Kyttä, M. & Hartig, T. (2002). Restorative experience, self-regulation and children’s place preferences. Journal of Environmental Psychology, 22, 387-398. doi:10.1006/jevp.2002.0277

Korpela, K., Hartig, T., Kaiser, F. & Fuhrer, U. (2001). Restorative experience and self- regulation in favorite places. Environment & Behavior, 33, 572-589. doi: 10.1177/00139160121973133

For more articles by this author, see: http://www.favoriteplace.info/Korpela_Kalevi.htm

Research questions

1. Bowler et al.'s (2010) review indicated a need for more rigorous and objective evaluation of interventions which aim to use the natural environment for health promotion and recommended that further research investigate compare effects for different populations, environments, and social contexts, and consider the longer-term significance of repeated exposure on health.
2. Single scene vs. multiple scenes vs. video - What are the differential psychophysiological effects of looking for a period of time at a single scene or multiple scenes or video of scenes?

IVs and DVs

There are many possible independent variables (IVs) that potentially could be manipulated or controlled. These broadly relate to the type of environment and type of activity.

Dependent variables (DVs) include physiological (such as heart rate, blood pressure, hormones) and psychological indicators of health (such as mood, stress, and cognitive capacity).

IVs

Natural vs Urban

1. 'Green' includes parkland, forests, fields (White et al.)
2. 'Built' includes roads, walls, buildings, constructions (White et al.)

• Natural scenes include forrests, canyons, desert landscapes, mountain ranges (Tinio & Leder, 2009)

1. "human-made" scenes include city skylines, bridges, road systems, houses (Purcell et al, 2001).
2. From most preferred and most highly rated on a Percieved Restorativeness Scale: Lakes, Hills, City streets, houses, industrial zone (Purcell et al.).

Pleasant vs Unpleasant

1. The 'pleasantness' and 'preference' of a scene have found to be dependent on mystery, coherence and nature (Herzog, 1989)

Water

1. Pretty et al. (2005) found water to contribute to the pleasantness of an image.
2. Water seems to effect the pleasantness (White et al. 2010).
3. Other studies have found water to have no effect.
4. Some studies have not used images containing water, claiming it to be a potentially confounding variable.
5. Water may be an important way in which we can manipulate the 'pleasantness' of of natural and urban environments. Many cities and towns have been built along coast lines and other bodies of water such as rivers and lakes, and as such can be considered as part of an urban landscape (White et al.).
6. Water seems to have a 'dose effect' (i.e. more water means higher restorative properties) (White et al.).

People

1. The presence of people (Herzog, Kaplan and Kaplan 1976, cited in Herzog 1989), animals in images effects their pleasantness. This can either be balanced by creating subcategories which include people, animals, objects or none of these. This would drastically increase the amount of categories (from 4 to 16), greatly increasing the length of time taken to complete our measures and placing undue inconvenience on participants (and due to our moderate sized sample, a between groups design with 16 conditions could be detrimental to the power (is this the right word?) of this design). Instead, the confounding effect of people and animals will be controlled for by excluding them from our images.

Weather

1. Weather can influence the pleasantness of a scene (White et al.), and should therefore be controlled for (i.e. all scenes should have similar weather conditions). People have been shown to dislike dark skies and thundery clouds (Pretty et al. 2005)

Green

1. Green scenes are prefered over brown ones (Pretty et al. 2005). Would this translate to an Australian sample, where much of the landscape is brown?

Trees

1. Trees contribute to pleasantness, as do sky-scrapers and city-scapes (Pretty et al. 2005)

Unpleasantness

1. Contributors to unpleasantness include: broken windows, rubbish, scaffolding, graffiti, other damage or degradation, abandonment or desertion (Pretty et al.)

Image quality

1. Tinio and Leder (2009) assessed differences in likability of natural versus human-made and high image quality (i.e. high resolution, vibrantly coloured, well-contrasting, sharp images). They found that natural images were liked more than human-made ones, and that high quality images were liked more than low quality ones. natural-high quality M = 5.47, human-made high quality M = 4.82, natural degraded M = 3.64, human-mad degraded M = 3.09.

Scene dimensions

1. Open vs. closed space
   1. Fear/anxiety in open spaces -

DVs

Mood

1. Positive affect
2. Negative affect

Stress/Arousal

1. Stress changes strongly correlated with negative affect changes (Rytir, 2011).

Cognitive capacity

1. Rees (2013)

Liking

• White et al. explicitly measured affect and arousal (i.e. asking participants to rate, on a scale from 1 to 10, how happy a picture made them feel). This method could be subject to demand characteristics where participants have heard of the restorative properties of natural scenes and answered their questions to suit what they had heard rather than what they had really experienced.

UC studies

Several Honours Thesis in Psychology students at the University of Canberra have conducted research studies about the psychological aspects of viewing natural scenes since 2011, under the supervision of James Neill.

Rytir (2011)

Pilot study

1. Photos were initially categorised using theories and previous research.
2. Used the general approach described in Pretty (2005) to assess the accuracy of photo categorization.
3. A group of participants was asked to rate the photos as either on an 11-point artificial-natural scale and an 11-point unpleasant-pleasant scale

Main study

1. Examined the effect of viewing natural, semi-natural, and natural image sets on mood (positive affect and negative affect) and stress.
2. Examined the role of "connectedness to nature" to determine whether connectedness to nature predicted the effects of viewing images on changes in mood in stress.
3. By and large, there were small to moderate positive effects of viewing more natural images on mood and stress and these effects did not relate to connectedness to nature. Thus, the health and well-being benefits of nature exposure do not appear to be dependent on one's sense of connectedness to nature.

Schlesinger (2013)

1. The effect of scene naturalness on the components of Attention Restoration Theory

Rees (2013)

1. The effect of image naturalness and preference on directed attention fatigue

Goch (2014)

1. The role of the five-factor model of personality in understanding the effects of viewing natural, semi-natural and artificial scenes on positive and negative affect

Hunter (2015)

1. Psychological effects of environmental sounds and scenes

O'Toole (2015)

1. The effects of water-based natural images on anger, sadness and stress

Method

Participants

• Participants for initial studies can be first year psychology students.
• Whilst it could be helpful to conduct computer lab classes for data collection, this is somewhat restrictive and the research design should allow for people to access the digital package and to watch and experience in their own time and place (via online survey/internet). This context (lab vs. normal) may be important and probably should be tested in later studies.

Image sources

• Wiki commons - we could create a special category e.g., commons:Category:Psychology of nature scenes
• Flickr - images with cc by a licenses can be imported to Wiki commons

Presentation

• Create timed slide presentations, then screen record and upload to Wiki commons, youtube etc.
• Present using online survey software (e.g., Qualtrics which allows for timing of responses).
• Randomly allocate participants to different conditions

Design

• The design could be between-subjects (e.g., one of the experimental stimuli per participant) or within-subjects (e.g., all stimuli per participant) or a mixed-design. This will depend partly on how length the measures are per exposure. A within-subjects design will probably be more powerful, but there may well be contamination/order effects to consider and a fully experimental design may be "purer".

Related projects

• Landscape study
• Psychology and the environment (APS Special Interest Group)
• In urban neighbourhoods, more trees equals less crime (Lisa Raffensperger, April 5, Discover)
• Green skins project, Curtin University

References

1. Abkar, M., Kamal, Mustafa, K. M. S., Maulan, S., & Maripan, M. (2010). Influences of viewing nature through windows. Australian Journal of Basic and Applied Sciences, 4(10), 5326-5361.
2. Alexander, C. (2002-2004). The nature of order: An essay on the art of building and the nature of the universe. New York: Oxford University Press.
3. Barton, J. & Pretty, J. (2010). What is the best dose of nature and green exercise for improving mental health? A multi-study analysis. Environmental Science and Technology, 44, 3947–3955. doi: 10.1021/es903183r
4. Bowler, D. E., Buyung-Ali, L. M., Knight, T. M., & Pullin, A. S. (2010). A systematic review of evidence for the added benefits to health of exposure to natural environments. BMC Public Health, 10(1), 456. doi: 10.1186/1471-2458-10-456.
5. de Vries, S., Claßen, T., Eigenheer-Hug, S., Korpela, K., Maas, J., Mitchell, R. & Schantz, P. Contributions of natural environments to physical activity: Theory and evidence base (pp. 205-244). In Nillson, Gangster, M., Gallis, C., Hartig, T., de Vries, S., Seeland, K., & Schipperijn, J. (Eds.) (2014). Forests, trees and human health. New York: Springer.
6. Frumkin, H. S. (2001). Beyond toxicity: Human health and the natural environment. American Journal of Preventive Medicine, 20, 234-240.
7. Herzog, T. R. (1989). A cognitive analysis of preference for urban nature. Journal of Environmental Psychology, 9, 27-43.
8. Kahn, H. K. Jr. et al. (2008). A plasma display window?—The shifting baseline problem in a technologically mediated natural world. Journal of Environmental Psychology, 28(2), 192-199.
9. Kaplan, S. (1995). The restorative benefits of nature: Towards an integrative framework. Journal of Environmental Psychology, 15, 169-182. Retrieved from http://www.sciencedirect.com/science/article/B6WJ8-4CF0KYK-M/2/3c6857403ffcf3563d0ced66b3bc672d
10. Kaplan, R., & Kaplan, S. (1989). The experience of nature. A psychological perspective. NY: Cambridge University Press.
11. McMahan, E. A., & Estes, D. (2015) The effect of contact with natural environments on positive and negative affect: A meta-analysis. The Journal of Positive Psychology, 10, 507-519, doi: 10.1080/17439760.2014.994224
12. Neill, J. T. et al. (2004). A psycho-evolutionary theory of outdoor education. Presentation at the International Outdoor Education Research Conference, LaTrobe University, Bendigo, Australia, July 6-9.
13. Pretty, J., Peacock, J., Sellens, M., & Griffin, M. (2005). The mental and physical health outcomes of green exercise. International Journal of Environmental Health Research, 15(5), 319-337. DOI: 10.1080/09603120500155963
14. Tinio, P. P. L., & Leder, H. (2009). Natural scenes ar indeed preferred, but image qulity might have the last word. Psychology of Aethetics, Creativity and the Arts, 3(1), 52-56. DOI: 10.1037/a0014835
15. Thwaites, K., Helleur, E., & Simkins, M. (2005). Restorative urban open space: Exploring the spatial configuration of human emotional fulfilment in urban open space. Landscape Research, 30(4), 525-547.
16. Ulrich, R. S. (1981). Natural versus urban scenes: Some psychophysiological effects. Environment and behavior, 13(5), 523-556. doi: 10.1177/0013916581135001.
17. Ulrich, R. S. (1983). Aesthetic and affective response to natural environment. In Behavior and the natural environment (pp. 85-125). Edited by Altman, I., & Wohlwill, J.F. New York: Plenum Press.
18. Ulrich, R. (1984). View through a window may influence recovery from surgery. Science, 224(4647), 420–421. doi:10.1126/science.6143402
19. Ulrich, R. S. (1986). Human responses to vegetation and landscapes. Landscape and Urban Planning, 13, 29–44. doi:10.1016/0169-2046(86)90005-8
20. Ulrich, R. S., Simons, R. F., Losito, B. D., Fiorito, E., Miles, M. A., & Zelson, M. (1991). Stress recovery during exposure to natural and urban environments. Journal of Environmental Psychology, 11, 201–230. doi:10.1016/s0272-4944(05)80184-7
21. White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D., & Depledge, M. (2010). Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes. Journal of Environmental Psychology, 30(4). DOI: 10.1016/j.jenvp.2010.04.004.

See also

• Green exercise
• List of images
• Journals
• Green exercise and emotion (Book chapter, 2013)
• Nature and emotion (Book chapter, 2013)
• Nature and psychological well-being (Book chapter, 2011)