As for this question, there is no fixed answer to it since it will have to take into account other factors that would affect and compromise one's ability to learn and recall new information. Factors would include, but are not limited, to as follows: person's tolerance to alcohol, size, alcohol content of the drink, food in stomach, duration of drinking, and so on. Though what usually is common for all people, drinkers or not, 2 - 4 would be enough to compromise one's ability to learn and recall new information. More than that would result to a more interesting effect.
