Which of the following task characteristics influence learning, along with the frequency of practice?

The option referring to overall task complexity is correct because task characteristics such as complexity play a critical role in how effectively individuals learn and retain information. When a task is complex, it often requires more cognitive effort and engagement, which can enhance the learning process. Furthermore, understanding the level of complexity allows trainers to tailor practice sessions to the learners' current skills and knowledge, helping to ensure that the practice is targeted and relevant.

Complex tasks may also necessitate more frequent practice to achieve mastery. If a task is too simple, it may not provide enough challenge for learners to engage deeply, while tasks that are too difficult can lead to frustration and disengagement. Therefore, balancing task complexity with the right frequency of practice can promote better learning outcomes and transfer of skills.

Comparatively, factors such as mild challenge level, instructor's experience, and duration of training can influence the learning environment but are not as directly linked to task characteristics as overall task complexity. For instance, a mild challenge level might not stimulate adequate cognitive load, while an instructor's experience can facilitate learning through better explanations and guidance, but it is not a task characteristic itself. Duration of training may affect retention but does not inherently address the difficulty level or the nature of the task being learned.