This is about any kind of responsibility that is perceived to lie on the shoulders of more than one individual. The nature of a responsibility is that as time passes, the execution of a specific action becomes more and more important, and eventually the failure to execute it produces negative results. The individual or group that has the responsibility is expected to execute the action and this expectation lives in those who perceive that nonperformance of the action produces negative results.

When the responsibility is shared, it is held by a group of people. If one person in the group performs the action, others don't have to. Notice that in a case where the others do have to perform the action, the responsibility is not shared, but rather each person has the personal responsibility to perform the action.

There are responsibilities in which more than one action are required, and sharing of such responsibilities can be handled without the difficulty I'm trying to illuminate. However, in order to accomplish this, it is necessary to assign each action to a single individual of the group. If any one of the actions is "shared" then the problem will eventually appear.

Members of the group will have the thought "Don't I take care of this more often than the others?" Eventually, this thought will be accurate, or else we have a situation in which the responsbility is not actually shared, but rather held as a personal responsibility by each member in turn. If the thought is never accurate, then the personal responsibility that is passed from member to member will not produce the intrinsic problem I'm about to explain. The passing of the responsibility can be explicitly recognized or hidden, but it is rare for it to be hidden and remain stable, for each of us has a different level of tendency to fulfill our duties so some member will usually perform the action more often than others. Also, members may start playing the waiting game, in which each one is waiting for one of the others to perform the action.

Whenever the thought is accurate, the person having the thought will have an increased sense of being exploited. However miniscule this feeling may be at the beginning, it is justified by the fact that the thought is accurate. If the thought is accurate, then it is clearly being thought by a person of the group who tends to be more responsible. The feeling of being exploited will, over time, inexorably damage the relationships that person has with the rest of the group, and may ultimately lead to abandonment of the group. This is the problem intrinsic to shared responsibility: the best people in the group are exploited by the rest of the group. This can and usually does happen within groups of two people, like marriages.

If the best members of the group, meaning those that perform the required action most often, do not pay attention, then it is likely that they will never realize that they are doing more work, and all will be fine. However, it is rare for the best members of a group to ignore the amount of work they do, especially when the work is the fulfillment of a shared responsibility.