Ecological Validity Definition
Ecological validity is the extent to which research findings would generalize to settings typical of everyday life. As such, ecological validity is a particular form of external validity. Whereas external validity refers to the overall extent to which findings generalize across people, places, and time, ecological validity refers more specifically to the extent to which findings generalize to the settings and people common in today’s society.
Ecological Validity Background and Distinctions
Validity has many faces, including internal validity (accurate claims about cause), construct validity (accurate claims about the nature of variables), and external validity (accurate claims about how processes and findings generalize across people, places, and time). Ecological validity is one aspect of external validity in which researchers ask whether research results represent what happens in everyday life. More specifically, ecological validity addresses whether an effect has been shown to operate in conditions that occur often for people in the population of interest.
In this regard, ecological validity is closely related to the concept of mundane realism. Experimental tasks are said to have mundane realism when they closely resemble activities that are common in natural settings. For example, activities in an experiment might be realistic in this mundane way when participants are asked to read a newspaper story about an obscure issue in a foreign country. This study might be considered as having a great deal of mundane realism because it uses activities common in everyday life (reading a newspaper). Yet the study may also be considered as lacking in experimental realism (the extent to which the activities are meaningful and have an impact on participants) if the topic of the newspaper article is uninteresting and fails to engage participants.
Ecological validity does not simply reflect an absence of experimental realism, because there are certainly many engaging and influential activities that form core aspects of everyday life. In fact, one might distinguish between mundane realism and ecological validity by noting that, in the real world, people would be relatively unlikely to spend time reading a newspaper article about a topic about which they know and care very little. Thus, although newspaper reading itself seems to reflect everyday activities quite well (mundane realism), the use of that activity in the experimental setting may diverge from the ways and reasons people typically read newspapers. That is, findings based on the use of this activity may lack ecological validity.
In this sense, ecological validity is also related to psychological realism (the extent to which the psychological processes operating in an experiment also occur in everyday life). When discussing psychological realism, it is important to distinguish between the specific activities and materials used in a study (mundane realism), the likely impact of the activities and materials (experimental realism), and the types of psychological processes that participants use to complete the activities in the study. Even if the activities in a study bear little resemblance to real-world activities (low mundane realism) and have relatively little impact on participants (low experimental realism), the thought processes that participants use in the study may be quite common in the real world (high psychological realism). For example, if a study involves judging words as quickly as possible as they appear on a computer screen, this would not be a typical activity in everyday life, and the words may not create strong reactions in research participants. However, if the words are activating concepts that then help people to quickly comprehend the next word on the screen, this may demonstrate a psychological process (concept activation) that is extremely common in everyday life.
Researchers might reasonably ask whether ecological validity is always valued. To be sure, all else being equal, researchers would prefer that their findings replicate in real-world settings. However, as noted earlier, psychological processes that would operate in many everyday settings may be more efficiently and effectively tested using methods that remove much of the messiness (lack of experimental control) of real-world settings. Especially when one is testing specific psychological theories and doing so by isolating particular variables within the theory, ecological or even external validity more generally may not be of the utmost importance. When seeking to intervene in specific applied settings, however, one would certainly want to make sure that the intervention of interest is able to influence behavior even with all of the messiness of the natural environment. This may be more likely if the intervention is developed on the basis of research that incorporates as many features of the real-world environment as possible.
Despite ecological validity being relevant to which settings a result might generalize, the reader should note that ecological validity is not the same as external validity. There is no guarantee that an effect found in a specific, ecologically valid setting is more likely to generalize across settings (a key aspect of external validity) than is an effect found in a more artificial laboratory setting. Although a study conducted in a coffee shop might produce results that are more likely to generalize to coffee shops, the results of the study may be no more likely to generalize across many settings (such as courtrooms, boardrooms, or classrooms) than a study conducted in a laboratory where background noise is more carefully controlled. Support for external validity can be garnered from replications of an effect at different points in time and in different places, even if all of those places are quite artificial and all lack ecological validity.
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