Some people need more church than others do. Some don’t need any at all. I’m OK with that. I’m not OK with the idea that everyone needs the same amount. On average, I need 74 minutes.
There’s no organization, including church, where everyone’s precise needs are met. If you don’t think so, next Sunday count how many people are actually paying attention.
Kirby - Salt Lake Tribune
Estimates for the length of human attention span are highly variable and depend on the precise definition of attention being used.
Focused attention is a short-term response to a stimulus that attracts attention. The attention span for this level is very brief, with a maximum span, without any lapse at all, that may be as short as 8 seconds.[2] This level of attention is attracted by a ringing telephone, or other unexpected occurrence. After a few seconds, it is likely that the person will look away, return to a previous task, or think about something else.
Sustained attention is the level of attention that produces the consistent results on a task over time. If the task is handling fragile objects, such as hand-washing delicate crystal glasses, then a person showing sustained attention will stay on task and will not break any dishes. A person who loses focus may break a glass or may stop washing the dishes to do something else. Most healthy teenagers and adults are unable to sustain attention on one thing for more than about 40 minutes at a time, although they can choose repeatedly to re-focus on the same thing.[2] This ability to renew attention permits people to "pay attention" to things that last for more than a few minutes, such as long movies.
Wiki - "Attention Span"
Elder Poelman in 1984 (coincidence?) clearly agreed with Kirby, that differing people need differing amounts of 'Church'.
So, three hours at Church is clearly unproductive as a method of indoctrinating the members...ehm...perfecting the saints. In fact, you could argue the three hour block has the opposite effect. I did as Kirby suggested and observed how many people were paying attention during Sacrament, Sunday School and Priesthood. It was less than fifty percent at any given time and for significant periods less than thirty percent.
There has to be a better way if the Church wishes to recruit and retain members...right?