expected to have. reporter: author of the learning habit was a contributing editor to the study that a little found that workload increases, so does the stress. they re getting work they don t us understand. they re getting work that s really, really stressful. reporter: so what are the guidelines for homework? the national education association and the national parent-teacher association recommend a 10-minute rule. ten minutes per night for first graders and ten additional minutes per night thereafter. the study found kin dd der gath ners are getting more than that. kids mostly come into school