Cognitive Strategies and Natural Environments Interact in Influencing Executive Function

Abstract

Exposure to natural environments and the adoption of specific cognitive strategies are each claimed to have a direct influence on executive mental functioning. Here we manipulate both factors to help determine whether they draw on common cognitive resources. Three experiments investigated links between environmental effects (nature vs. urban video tours) and strategic effects (active vs. passive instructional approaches to the task). Each experiment used a pretest-posttest design and assessed executive mental functioning using a backward digit span task and Raven's progressive matrices. Experiment 1 manipulated participants' cognitive strategy through explicit instructions in order to establish a link between cognitive strategy and executive mental functioning. Experiment 2 used a pair of 10-min video tours (urban, nature) to examine the relationship between environmental exposure and executive mental function on the same tasks, replicating previous findings with the backward digit span task and extended them to a new task (i.e., Raven's progressive matrices). In Experiment 3, these two manipulations were combined to explore the relations between them. The results showed that the nature video tour attenuated the influence of task instructions relative to the urban video tour. An interaction between environmental video exposure and cognitive strategy was found, in that effects of cognitive strategy on executive function were smaller in the nature video condition than in the urban video condition. This suggests that brief exposure to nature had a direct positive influence on executive mental functioning.

Keywords: additive factors logic; attention restoration theory; cognitive strategies; executive functioning; natural environments; visual attention.

Figure 1

A schematic of the experimental design and hypothesis being tested in this study. Attention restoration theory claims that natural environments (an experimental factor) influence backward digit span tasks (an outcome) through their effect on central executive functioning (a latent variable). A strong test of this hypothesis is given by simultaneously varying another experimental factor (cognitive strategy) which is also shown to influence executive functioning. If the environment has an influence on other latent variables (e.g., sensory register, decision making) then additive results are possible, because each experimental factor is influencing a different latent variable. If both experimental factors influence the same latent variable, then interactive results are predicted.

Figure 2

Mean difference in standardized scores before and after receiving cognitive strategy instructions. Error bars represent one standard error around the mean. Positive scores indicate improvement from pre- to post-testing; negative scores indicate a decrement over time.

Figure 3

Mean difference in standardized scores before and after three different video viewing conditions. Error bars represent one standard error around the mean. Positive scores indicate improvement from pre- to post-testing; negative scores indicate a decrement over time.

Figure 4

Mean difference in standardized scores before and after four combinations of strategy and video viewing conditions. Error bars represent one standard error around the mean. Positive scores indicate improvement from pre- to post-testing; negative scores indicate a decrement over time.