This study (2008) includes two experiments that show how walking in nature or even just viewing pictures of nature can improve directed attention. Researchers compared the restorative effects on cognitive functioning of interactions with either natural or urban environments. Their hypothesis that nature has a more restorative effect is based on attention restoration theory (ART): nature is filled with intriguing, modest stimuli, which allows top-down directed attention abilities a chance to replenish. Urban environments on the contrary are filled with attention capturing stimulation requiring directed attention, thus making them less restorative.

Both of the experiments measured how much participants improved in their tasks after different treatments. The firt test included a backwards digit-span test, where participants heard digit sequences and were required to repeat them in a backwards order. This task depends highly on directed-attention abilities, as it incorporates short-term memory. After the test they were randomly assigned to take a walk either at a park or traffic-heavy city streets, and did the test again.

In the second experiment, three different attentional functions were measured from the participants: alerting, orienting, and executive attention. Researcher predicted that interactions with nature would improve executive functions, but not the other two as they require less cognitive control. Participants did the digit-span test like in the first experiment, and they then performed in a task called ANT where they responded to the direction of a centrally presented arrow according to certain cues. Participants then viewed pictures of either nature or urban settings, after which they performed the tests again.

The results showed that:

• Test 1: Improvements in backwards digit-span performance were significantly greater when walking in nature (1.5 digits) than urban environment (0.5 digits), and nature improved performance beyond simply repeating the task a second time
• Test 2: Improvements were found only on the executive proportions of the ANT and only after viewing pictures of nature compared to urban areas. The test confirms that improvements achieved through nature were selective to directed attention

The study concludes, that restorative value of nature improves cognitive functioning. Even when both of the environments were essentially peaceful in test two (quiet experiment room), only viewing pictures of nature produced cognitive improvement.