The gap refers to the observed differences in people's behavior depending on whether their decisions are made towards clearly outlined and described outcomes and probabilities or whether they simply experience the alternatives without having any prior knowledge of the consequences of their choices.
[4] Specifically, people's decisions differ depending on whether the described prospects are framed as gains or losses, and whether the outcomes are sure or probable.
For described prospects, people tend to assign a higher value to sure or more probable outcomes when the choices involve gains; this is known as the certainty effect.
[4] Previous studies focusing on description-based prospects suffered from one drawback: the lack of external validity.
Contrary to the results obtained by prospect theory, people tended to underweight the probabilities of rare outcomes when they made decisions from experience.
[5][6] However, people tended to choose the riskier choice when deciding from experience for tasks that are framed in terms of gains, and this, too, is in contrast with decisions made from description.
Another variable which may be driving the results for the experience-based decisions paradigm is a basic tendency to avoid delayed outcomes: alternatives with positive rare events are on average advantageous only in the long term; while alternatives with negative rare events are on average disadvantageous in the long term.
Consistent with this notion, it has been found the increasing the short term temptation (e.g., by showing outcomes from all options; or foregone payoffs) increases the underweighting of rare events in decisions from experience [8] Since experience-based studies include multiple trials, participants must learn about the outcomes of the available choices.
Biases for more salient memories, then, may be the reason for greater risk seeking in gains choices in experience-based studies.
Whereas in experienced prospects, people tend to underweight the probability of the extreme outcomes and therefore judge them as being even less likely to occur.
A highly relevant example of the description-experience gap has been illustrated: the difference in opinions on vaccination between doctors and patients.
Due to the different ways in which doctors and patients learn about the side effects, there is potential disagreement on the necessity and safety of vaccination.
[5] Typically in natural settings, however, peoples’ awareness of the probabilities of certain outcomes and their prior experience cannot be separated when they make decisions that involve risk.