TABLE 5.
The independent variables from Table 3 with examples of design features applicable to each variable that are considered likely to support a high level of ecological validity of a study, and the rating of how well this is currently and generally achieved in clinical and research settings
| Independent variables | Examples of design features that presumably support a high level of ecological validity | Current state of the art in the | ||
|---|---|---|---|---|
| Clinic | Laboratory | Field | ||
| Sources of stimuli | ||||
| Stimulus sources | The inclusion of varied natural sound sources; nonevent speech; different talkers (e.g., male/female, adult/child, native/accent); familiar talkers. | Low | Medium | High |
| Stimulus materials | The inclusion of context-dependent cues such as Lombard effects; variation in speed; disfluencies; interjections, and/or emotion. | Low | Medium | High |
| Multimodal stimuli | Multiple modalities carry manipulations that are consistent and natural for the intended real-world scenario. | Low | Medium | High |
| Other people | Other people are represented in a manner (e.g., modalities, behavior) that is consistent with the level of realism in other aspects of the scenario’s presentation. | Low | High | High |
| Environment | ||||
| Acoustic field | The presentation of realistic sound levels; spatial relationships; reverberation. | Medium | High | High |
| Interaction of environment and hearing devices | The acoustic field (including direct and reflected sound) is picked up by the device’s microphone/s in a natural manner. | Low | Medium | High |
| Dynamic aspects | The presentation of moving sources is realistic for the intended real-world scenario. | Low | Medium | High |
| Modalities | The presentation includes visual cues (e.g., AV speech cues, nonverbal background cues); tactile cues in interferer stimuli; inertia in the environment. | Low | Medium | High |
| Context of participation | ||||
| Participant preparation | Clear instructions and familiarization of study tasks are provided. | Medium | Medium | Medium |
| Semantic associations | The situations are familiar and relevant to the participant. | Medium | Low | High |
| Motivation | The scenario and task elicit appropriate engagement and motivation. | Medium | Medium | High |
| Familiarity | The participant feels comfortable with physical aspects of the experiment. | Medium | Medium | High |
| Psych/physiological state | The participant is not abnormally stressed or anxious due to factors beyond the study design. | Low | Low | High |
| Task | ||||
| Nature of task | The tasks included are appropriate for the intended real-world scenario. | Medium | Medium | High |
| Nature of task if speech | The speech tasks included resemble those that might occur in the intended real-life scenario. | Low | Low | High |
| Complexity | Any additional tasks included stimulate natural mental processes as they might occur in the intended real-world scenario. | Low | Medium | High |
| Degree of constraint | The participant is free to perform the task in whatever ways feel natural in the intended real-world scenario. | Low | Low | Medium |
| Exploratory movement | The participant is allowed freedom of gaze, head movement, and/or body movement similar to that they would have in the intended real-world scenario, and such movements produce realistic changes in the stimuli. | Low | Medium | High |
| Interaction | Interaction with other persons represented or actually present elicits plausible behaviors from all involved. | Low | Medium | High |
| Predictability | The task possesses predictability similar to what would be present in real life. | Medium | Medium | High |
| Distractors | Any distractors are plausible for the intended real-world scenario. | Low | Low | High |
| Individual | ||||
| Variety of personality and demographic factors | Participant recruitment includes stratification or registration of those personal and demographic variables believed to have potential influence. | High | Low | Low |