Do individuals see what they expect to see in a physics experiment?: Revisiting Schlichting’s example of the illumination of a filament

The present study investigates the alignment between individuals’ preconceived naïve conceptions

and their actual observations during a physics experiment. Building on Schlichting’s (1991) well-cited

but anecdotal example of a classroom experiment, we conducted an online survey involving 158

participants to assess their predictions, reasonings, and subsequent observations of a light bulb filament’s

illumination. Our results indicate a high consistency between participants’ predictions and

their reasonings but only very weak alignment between these predictions and reasonings and their

actual observations. Moreover, logistic regression analyses revealed significant but modest effects of

predictions and reasonings on observed outcomes. These findings imply that while naïve conceptions

can influence individuals’ observations, the impact is not as predictive as some anecdotal examples

within the literature on physics education might suggest.