  Developing computational models for automatic affect prediction requires
valid self-reports about individuals' emotional interpretations of stimuli. In
this article, we highlight the important influence of the temporal distance
between a stimulus event and the moment when its experience is reported on the
provided information's validity. This influence stems from the time-dependent
and time-demanding nature of the involved cognitive processes. As such, reports
can be collected too late: forgetting is a widely acknowledged challenge for
accurate descriptions of past experience. For this reason, methods striving for
assessment as early as possible have become increasingly popular. However, here
we argue that collection may also occur too early: descriptions about very
recent stimuli might be collected before emotional processing has fully
converged. Based on these notions, we champion the existence of a temporal
distance for each type of stimulus that maximizes the validity of self-reports
-- a "right" time. Consequently, we recommend future research to (1)
consciously consider the potential influence of temporal distance on affective
self-reports when planning data collection, (2) document the temporal distance
of affective self-reports wherever possible as part of corpora for
computational modelling, and finally (3) and explore the effect of temporal
distance on self-reports across different types of stimuli.
