Brookfield explains that the student lens has been critically important to his own development as an instructor. He makes the argument that unless you know how your students are responding to the material and the instruction, you cannot have any idea whether or not your teaching is having an impact and whether the instructional approach needs to be adjusted. He states that student mid-course feedback must be anonymous for students to be able to provide it honestly. But he also explains that instructors must keep the promises they make otherwise the instruction and the request for feedback will be perceived to be inauthentic. But note that although not all student feedback may be justified, all feedback must have a response from the instructor. If students’ feedback is mistaken or unjustified, instructors must still explain to students why the suggestions are not being enacted.
The lens of our colleagues helps us to compare or check our experiences with others. Is our experience unique or is it shared by others? Trusted friends are able to listen to us and carefully describe the experience and our understanding of its significance before explaining how they see it from their perspective. This can result in useful suggestions for interpreting and responding to our own experiences.
Brookfield suggests that personal experience tends to be discounted in our Enlightenment-influenced culture in which only objective data and analysis are acceptable pieces of evidence. Anecdote is valid evidence. It may be specific and applicable to a particular circumstance or context. But that does not make it invalid - it simply means that it may not be broadly generalizable. It doesn't mean that our own anecdotes may not be pertinent to our own development as instructors.
Finally, the theoretical lens is explained to be the most difficult to cultivate and incorporate, but that it can be the most powerful. Difficult because it requires seeking out the journals and browsing the articles and perhaps taking the time to work through difficult ideas. But the ability to use a cogent framework of analysis to understand our own teaching experiences, unstated biases, and automatic responses can help us uncover what underlies our instructional choices and illuminate alternatives. I think it can help you avoid path dependency or perhaps switch trajectories by seeing if we are comfortable in particular frameworks, ideologies, or philosophical schools.
What all of these lenses do is to help us uncover our unstated biases and assumptions and indicate alternative approaches to our teaching and students.