Understanding Biases in Research Videos
Video offers the researcher a large gain in data gathering capabilitiescompared to audio recording or direct observation. The gains can leadresearchers to overlook the limitations of the medium, leading to dangerousmisconceptions. Three misconceptions are discussed below, along withsuggestions about how the researcher can control the biases of the medium.
1: Video captures what an observer would see
Compared to the human eye, a video camera has many limitations. For example,because video has low resolution, it is generally impossible to simultaneouslysee writing on a document or blackboard without zooming in. But such zoomingwill exclude the broader activity. A human eye can easily see both at once.
Video also has a low contrast ratio. This means that it can tolerate only alimited range of brightness. Whereas a human observer can see both an overheadprojector image and participants in the darkened room, a video camera willoverexpose the image or underexpose the participants.
Video has less depth of field than a human eye. This means it takes constantwork to keep different elements of a situation in focus in a video camera. Ingeneral, we are unaware of focussing problems as direct observers. Video alsohas a narrower field of vision, especially since direct observers can rapidlyturn their head to track action as it occurs. A live observer can easy watchfaces of two participants who are having a dialog across the classroom. Asingle video camera that tries to move from participant to participant willmake the viewer sea-sick.
Audio microphones have less selectivity than human hearing. In general, it ismuch easier to attend to one conversation out of many when you are directlyobserving the situation. In a video recording, any extraneous noise becomes veryannoying and distracting. While, you listen in person such noise would not interfere with your understanding. With video, a situation with overlapping noise can make a conversation impossible to understand.
2: Video has no point of view
In part because of the limitations above, the process of recording introduces adistinctive point of view on the proceedings. This point of view can severelydistort the underlying event and impede inquiry.
For example, in recording the audio portion of the event, it is good practiceto put microphones as close to the participants as possible. However, aunidirectional lapel microphone on the teacher can do an exceptional job ofselecting the teacher's voice and reducing classroom noise. This can make theclassroom seem unnaturally "dead." Conversely, a poor microphone choice andplacement (e.g. placing a lapel mike in the middle of a classroom) can pick up every cough and chair squeak, making a teacher hard tohear. This amplified background noise can make a classroom seem chaotic,unruly, or inattentive.
Likewise, one might put microphones near a particular group of students. Thesemicrophones can pickup whispered comments that otherwise would be inaudible toan observer. If students are making disparaging remarks, the classroom climatemight appear very different than it appears to an observer. If only a goodstudents have microphone, the class will seem better than if only a few badstudents have microphones.
Video images are also highly composed. Distortions can occur by focussing onone participant to the exclusion of others. Using direct video out from acomputer screen will capture a flicker-free image of the screen, but missparticipants gestures in front of the screen. Focussing on materials studentsare using can lead to neglect of their facial expressions.
In general, there is no way to achieve a neutral point of view. You will haveto clarify your purposes in making a video recording, and use this to guideyour construction of a video point of view.
3: Video captures context
Because video captures so many more features of human interaction than do othermedia, it is common to say that video captures context. To say whether contexthas been captured, one needs some definition of what it is. As a workingdefinition, let's assume that context refers to those aspects of the sharedsituation that are available to the participant and relevant to the meaning oftheir actions.
Assuming this definition, it is clear that video can capture many aspects oflocal, short-term context, like the materials students are manipulating. Butvideo is a poor medium for preserving non-local, long-term context. Forexample, while working together, the students know what they did yesterday andthe day before. Capturing a long-term sequence on video is difficult, andtime-consuming to watch. A journal or diary is much better at capturingchronological contextual information. Likewise, a teacher knows a lot about thepersonal history of each of her students. A transcribed interview is a muchbetter technique for gaining access to this context. In some situations, like aschool playground, participants move rapidly among many activities andsettings. Giving an appropriate overview of this activity on video would bevery challenging. Field notes from participant observation might give a morecoherent view of the playground context.