The answer lies within the scope of analysis of a fairly young Economics subdiscipline: BEHAVIORAL ECONOMICS. Behavioral economics increases the explanatory power of economics by providing it withmore realistic psychological foundations.

What is Behavioral Economics?Behavioral economics [applies] scientific research on human and social cognitive and emotional [patterns] to better understand economic decisions and how they affect market prices, returns and the allocation of resources. The fields are primarily concerned with the rationality, or lack thereof, of economic agents. Behavioral models typically integrate insights from psychology with neo-classical economic theory... Behavioral analyses are mostly concerned with the effects of market decisions, but also those of public choice...
Behavioral economics and behavioral finance are closely related fields that have evolved to be a separate branch of economic and financial analysis which applies scientific research on human and social, cognitive and emotional factors to better understand economic decisions by, say, consumers, borrowers, investors, and how they affect market prices, returns and the allocation of resources.

The field is primarily concerned with the bounds of rationality (selfishness, self-control) of economic agents. Behavioral models typically integrate insights from psychology with neo-classical economic theory. Behavioral Finance is another similar field of knowledge that evolved during since 1970s.

Behavioral analysts are mostly concerned with the effects of market decisions, but also those of public choice, another source of economic decisions with some similar biases towards promoting self-interest.

Recommended readings: Behavioral Economics: Past, Present, FutureColin F. Camerer(Carnegie-Mellon University)
The Marketplace of PerceptionsCraig Lambert(Harvard Magazine)