Introduction
Attention is a constant cognitive process that underlies all of our daily decisions, tasks, and activities. Every second, our brains are constantly selecting certain things in our environment for further processing while ignoring or neglecting others. Exogenous orienting is a form of bottom-up processing wherein our attention is guided by our external environment. This sort of attention is also known as involuntary attention because it requires a relatively low degree of effort. In contrast, endogenous orienting (also known as directed attention) is an effortful, top-down form of attention guided by the perceiver (That’s you!).
Endogenous Orienting as a Cognitive Resource
Kaplan & Berman (2010) suggest that directed attention (endogenous orienting) is a shared resource for two important cognitive mechanisms: executive functioning and self-regulation. They reason that both executive functioning and self-regulation require us to effortfully attend to the appropriate stimuli while effortfully suppressing stimuli that are unrelated to our goals.
If the authors are correct and these two mechanisms do share a cognitive resource, then a demanding task in either domain should deplete this resource and impose costs on the other domain. A great deal of evidence supports this relationship. Most famously, in Baumeister et al.’s (1998) “Chocolate and radish” experiment, participants sat in a room that smelled like fresh baked cookies and were presented with cookies and other chocolate treats. While participants in one group got to indulge in the sweet treats, participants in the experimental group were asked to eat radishes instead, leaving the sweets alone. Afterwards, participants who were forced to choose radishes over chocolate were less persistent in an executive functioning task.
Likewise, populations with attentive deficits (e.g. the elderly, ADHD patients, those who suffer from depression) tend to exhibit impaired performance on self-regulation and executive functioning tasks (Kaplan & Berman, 2010). While it has been suggested that glucose may be a more fundamental resource for these cognitive mechanisms (Gaillot et al., 2007), it seems likely that endogenous orienting is essential (unless these mechanisms become learned, automatic or habitual).
Attention Restoration Therapy and Nature
Along with normal self-regulation demands, daily executive functioning tasks such as work or homework may significantly deplete our ability to attend to relevant stimuli. These everyday attentional demands can result in directed attention fatigue, which can negatively impact our mood and decision-making (Edwards, 2010).
The most common way we restore this depleted resource is through sleep. Another promising method of attention restoration is meditation. In either case, we give our capacity for endogenous orienting a rest by not effortfully utilizing directed attention. Kaplan and Berman suggest a third way of resting and restoring our directed attention: we can enter an environment which relies almost exclusively on exogenous orienting (involuntary attention). Urban environments include a wide range of stimuli processed with exogenous orienting, but they also impose too many demands on directed-attention such that our endogenous orienting takes over. For example, we may have to avoid traffic or ignore billboard advertisements (Kaplan & Berman, 2010).
“On a busy city street, it’s probably more adaptive to have a shorter attention span . . . If you’re too fixated on something, you might miss a car coming around the corner and fail to jump out of the way”
-Sara Lazar, PhD. (professor at Harvard Medical School and director of Massachusetts General Hospital Laboratory for Neuroscientific Investigation of Meditation) (Edwards, 2010).
In contrast, natural environments, through the concept of soft fascination, engage our bottom-up attention processing (exogenous orienting) without imposing these types of demands on directed attention. Kaplan & Berman propose one essential criterion and three helpful criteria which natural environments must meet in order to be considered restorative for our directed attention:
- (Essential) They must include automatic, effortless stimuli to engage bottom-up processing. For example, a forest with a multitude of trees, plants, and other organisms which engage our exogenous orienting without taxing our directed attention.
- They should be compatible with our goals. If we have to go out of our way or spend too much money to visit a national park, we attend to how this experience conflicts with our goals, directly activating our endogenous attention.
- The environment should be large enough to be explored, or at least large enough to imagine exploring it.
- The environment should be sufficiently “away” from one’s usual environment to avoid interaction with routine directed attention tasks.
So far, a number of studies support the efficacy of natural environment interventions for restoring directed attention. Recovering cancer patients who elected nature walks as restorative therapy scored better on attentional measures than the control group at the end of the study (Cimprich, 1993). Ottosohn and Grahm (2005) found that an intervention conducted outdoors improved directed attention in elderly participants significantly more than a similar intervention indoors. Controlling for socioeconomic status, Kuo(2001) demonstrated that residents of an urban housing project surrounded by vegetation scored higher on attentional measures than residents whose buildings were not surrounded by vegetation. Kaplan and Berman present an exhaustive list of similar evidence in their 2010 article, which can be found below.
It appears that exposure to natural environments can improve our executive functioning and self-regulation by restoring our oft-depleted resource of directed attention. Of course, there are other explanations for the effect of nature on directed attention. Some suggest that nature improves cognitive function in general by decreasing stress, while others take an even further step back and attribute these effects to a general human love of nature – biophilia. Still, we should not overlook the restorative effects of nature on endogenous orienting, nor the benefits of Attention Restoration Therapy in general.
Beginning at 26:10, Dr. Marc Berman explains the benefits that natural environments can have on directed attention (and thus, on executive functioning and self-regulation). If you’re interested, watch the video from the beginning to learn about the more general restorative effects of nature.
References
Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: is the active self a limited resource?. Journal of personality and social psychology, 74(5), 1252.
Cimprich, B. (1993). Development of an intervention to restore attention in cancer patients. Cancer nursing, 16(2), 83-92.
Edwards, S. (2010, December 22). City Life and the Brain. On The Brain – Harvard Medical School. https://hms.harvard.edu/news/city-life-and-brain-12-22-10
Gailliot, M. T., Baumeister, R. F., DeWall, C. N., Maner, J. K., Plant, E. A., Tice, D. M., … & Schmeichel, B. J. (2007). Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. Journal of personality and social psychology, 92(2), 325.
Kaplan, S., & Berman, M. G. (2010). Directed attention as a common resource for executive functioning and self-regulation. Perspectives on Psychological Science, 5(1), 43-57.
Kuo, F. E. (2001). Coping with poverty impacts of environment and attention in the inner city. Environment and behavior, 33(1), 5-34.