Final answer:
The mere ownership effect is a cognitive bias that makes individuals value an object more after obtaining it, and this effect can strengthen over time. It can happen quickly, to anyone, and does not necessitate a long-term possession or significant attachment to the object.
Step-by-step explanation:
An accurate statement about the mere ownership effect is that it occurs almost immediately when an individual obtains an object and it increases with time of ownership. The mere ownership effect is a cognitive bias that causes people to value an object more once they own it, regardless of the object's objective value. This effect does not require a long duration of possession; it can happen swiftly and intensify over time as the object becomes more integrated with the individual's identity. It is also not limited to wealthy individuals or those with extensive possessions. Additionally, while the object may become part of an individual's extended self, this is not a prerequisite for the mere ownership effect to occur.