This study examined the instructional effectiveness with which different job aid types facilitated learner achievement of different types of learning objectives and identified the degree to which low and high prior knowledge individuals profit from different job aid types. The instructional content used in the study was an instructional module on the parts and functions of the human heart. Participants (n=300) were randomly assigned to one of five treatments complemented with different job aid types, i.e., control (no job aids), cueing, association, proceduralized, and analog job aid types. After interactions with the instructional module, participants received four posttests, each measuring different educational objectives. Research findings indicated that when job aids are used following instruction: (1) they are not equally effective in facilitating learner achievement of different types of educational objectives; (2) they do not reduce learning differences between low and high prior knowledge learners; and (3) there is an insignificant interaction between job aid type and prior knowledge level. (Contains 32 references.) (MES)