Thus far I've noticed that if I set up a bunch of tasks for one Sim, say to tend the garden and then harvest all, and then I send hubby to the gym to build fitness skill, when I return Sim #1 hasn't done the tasks that were assigned to her when I left. When I return she's just dancing to the stereo or using the observatory. She doesn't seem to continue with any of the tasks I've set for her, so she's not likely to build skills unless I'm there to monitor it. I don't think she's earning logic skill for using the observatory if I'm not there to see it if that makes any sense.
IDK if this answers your question or not though.