When experiencing an activity profile, specific emotional responses emerge, which will be taken into account the next time that this activity profile will be evaluated during the decision-making process. When implementing an activity profile, individuals experience the actual state of the activity attributes. The experienced utility of an activity profileat time / equals:
where is 1, if state n of the attribute j was experienced at time t, otherwise equals to 0. is the surprise that an individual experiences at time t.
If the cognitive expected utility deviates from the experienced utility, negative or positive emotions regarding this experience event emerge. The emotional value of an experience event of an activity profile at time / equals to:
If an activity profile is experienced several times, the emotional values of the experience events will be accumulated and result in a positive or negative overall affective value of that activity profile. The emotional value of an activity profile at time /, under context c, is:
where is the trade-off between accumulated past emotional values and the
most recent ones. This emotional value is incorporated in the overall expected utility of the activity profile ik at time /, under context c (where both a cognitive and an emotional component are included):
where is the trade-off between rational (based on expected utility) and affective behaviour (based on emotional value). When increases, emotionally driven behaviour emerges, whereas when decreases, affective responses are taken less into account during the evaluation process of the activity profiles.
Choice set formation
During the decision-making process, an individual evaluates a number of activity profiles and arrives at a single selection, which is actually the choice of that individual at that time and under a specific context. However, due to memory restrictions, or due to limited information, usually (s)he is not aware of all the activity profiles that are included in the universal choice set. Instead, only those activity profiles that (s)he is aware of, will be considered during the decision-making process. The extent
to which an individual is aware of an activity profile is contingent on memory and follows the processes of memory decay and reinforcement. The awareness level of an activity profile ik at time t, under context c, equals to:
where is the awareness retention rate and is the context-wise
awareness reinforcement parameter.equals to 1 if the activity profile was experienced at time /- 1, otherwise it is 0. equals to 1 if the context c was experienced at time /- 1, otherwise equals to 0. Thus, the stronger the emotional impact of the event experience, the longer the activity profile stays in memory. At time /, a choice set consists of those activity profiles whose awareness level exceeds a threshold, reflecting limited human memory retrieval ability. Thus, the choice set of an individual for activity type k, under context c, at time t, is:
where ω is the minimum awareness level for event memory retrieval ability.