This paper addresses the issue of ordering effects in choice experiments, and in particular how learning processes potentially affect respondents' stated preferences in a sequence of choice sets. In a case study concerning food quality attributes of chicken breast filets, we find evidence of ordering effects in a sequence of 16 choice sets, where the last eight choice sets are identical to the first eight. We find evidence of changes in preferences. More precisely there are differences in preferences for the price attribute for the two identical sequences. Moreover, we find a reduction in the error variance for the last eight choice sets relative to the first eight choice sets. This is mainly caused by very high error variances in the first two choice sets. These results imply that learning effects in terms of institutional learning as well as - though in our case only to a limited extent - preference learning can indeed be of significant structural importance when conducting CE surveys.