Allora siamo partiti inquadrando il discorso (l'investitore) come una "macchina" che elabora informazioni (psicologia cognitiva) e che si trova a frontaggiare con determinati stili situazioni stressanti che gli vengono poste dall'ambiente (coping). Non sempre questa le decisioni che prendiamo vengono fatte sulla logica e sull'attento esame delle variabili (euristiche). A questo punto allora Kahnemann e Tversky hanno proposto
LA TEORIA DELLA PROSPETTIVA
Il valore che diamo agli eventi possibili è sempre soggettivo e dipendente dallo status quo
Una variazione marginale negli esiti prospettati ha un effetto sulla scelta che diminuisce man mano che ci si allontana dal punto di riferimento
L’entità di piacere provato per la vincita di una data somma non è equivalente all’entità di dispiacere provato per la perdita di una somma equivalente (l’impatto emotivo dipende dal framing)
Grazie a questa teoria vince nel 2002 il Nobel per l'economia
http://en.wikipedia.org/wiki/Daniel_Kahneman
http://en.wikipedia.org/wiki/Prospect_theory
Some behaviors observed in
economics, like the
disposition effect or the reversing of
risk aversion/
risk seeking in case of gains or losses (termed the
reflection effect), can also be explained by referring to the prospect theory.
The
pseudocertainty effect is the observation that people may be risk-averse or risk-acceptant depending on the amounts involved and on whether the gamble relates to becoming better off or worse off. This is a possible explanation for why the same person may buy both an
insurance policy and a
lottery ticket.
An important implication of prospect theory is that the way economic agents subjectively
frame an outcome or transaction in their mind affects the utility they expect or receive. This aspect has been widely used in
behavioral economics and
mental accounting. Framing and prospect theory has been applied to a diverse range of situations which appear inconsistent with standard economic rationality; the
equity premium puzzle, the
excess returns puzzle and
long swings/ PPP puzzle of exchange rates through the endogenous prospect theory of Imperfect Knowledge Economics, the
status quo bias, various gambling and betting puzzles,
intertemporal consumption and the
endowment effect.
Another possible implication for economics is that
utility might be reference based, in contrast with additive utility functions underlying much of
neo-classical economics. This means people consider not only the value they receive, but also the value received by others. This hypothesis is consistent with
psychological research into
happiness, which finds subjective measures of wellbeing are relatively stable over time, even in the face of large increases in the standard of living (Easterlin, 1974; Frank, 1997).
Military historian John A. Lynn argues that prospect theory provides an intriguing if not completely verifiable framework of analysis for understanding
Louis XIV's
foreign policy nearer to the end of his reign (Lynn, pp. 43-44)
