Usability of Pictorial Assembly Instructions for Young Children

This human factors research demonstrated the importance of instruction design on assembly performance and self-efficacy in young children. The mixed-method usability study evaluated the effect of gender, age, toy, and experience on assembly performance, frequency and duration of instruction looks, subjective evaluations, and usability problems. A total of twenty-four boys and girls, six- and nine-year-olds, assembled K'NEX, LEGO, BIONICLE, and Lincoln Log toys using the accompanying pictorial assembly instructions. Other research objectives included recommending key usability measures for instruction designers, developing a model of assembly self-efficacy, and evaluating traditional usability methods for use with children.

Not surprisingly, quantitative results revealed that the older children assembled the toys more quickly and accurately with fewer usability problems. Six-year-old girls had the highest rate of mistakes. The nine-year-olds required fewer instruction looks of shorter duration than the six-year-olds. With few exceptions, toy comparisons were similar across subjective and objective measures. Thirty-two instruction design usability problems were described and illustrated and resulted in twenty-seven design recommendations. For example, more than half of the children omitted components added to the main assembly in the presence of a subassembly construction suggesting that the subassembly should be in a separate frame.

Principal components analysis of all quantitative measures revealed four key components for the usability testing of pictorial assembly instructions: performance, satisfaction, difficulty, and previous experience.

A qualitative analysis of the think-aloud data and observations, using Grounded Theory, produced a model of assembly self-efficacy from child users’ psychosocial and cognitive perspectives that affirmed the importance of user-centered instruction design. Girls exhibited lower self-efficacy and a greater tendency toward internal attributions, which was exacerbated by assembly of a boy-oriented toy. Six-year-old children were more affected by excess extraneous cognitive load and inaccurate information, such as color mismatches between the instructions and object.

Adaptations of traditional usability methods and instruments were effective with children. They included video training for thinking aloud, visual-analog rating scales, and pictorial ranking instruments. A small head-mounted camera provided an economic means for gathering gross instruction encoding times and for better understanding the user's perspective.