Positive psychology thus provides a foundation for coaching. Coaching psychology has been considered a type of applied positive psychology. Positive emotions motivate individuals to enhance their abilities and competencies. The broaden-and-build theory by Barbara Fredrickson posits that positive emotions can play a role in sparking not just motivation, but also actions that are productive and beneficial. In coaching, encouraging positive emotions is emphasised in order to inspire clients to take concrete action towards their goals. Aside from emotions, full engagement in activity is also a factor in maximising one's performance. Mihaly Csikszentmihalyi described this level of maximal involvement in a task as flow. In other words, individuals experiencing flow are "in the zone". Coaches play a role in setting an environment that induces flow. This can be achieved through clear and consistent goal-setting. Providing clear and immediate feedback also keeps the client informed about whether their actions are helping achieve their goals. Coaches also help strike a balance between challenge and skills as tasks that are too easy or too difficult for the client may hinder goal-achievement. Operant conditioning (as described by B. F. Skinner) views learning as a process involving reinforcement and punishment. Coaches are encouraged to always reinforce healthy and productive behaviours through verbal reinforcement, such as motivational words and images. Intrinsic reinforcement (i.e. reinforcement from within the individual) can also play a huge role in improving performance and encouraging goal-directed action. Though punishment can direct clients towards desired behaviours, performance may be hindered by unwarranted side effects, such as anxiety and resentment towards the coach. David A. Kolb's experiential learning theory posits that individuals learn through their experiences. Experiential learning is facilitated by self-reflection, self-assessment and action. Coaches can encourage critical self-reflection of experiences through "coaching logs" wherein coachees analyse their thoughts and emotions in various incidents and circumstances. This helps clients examine and challenge their own beliefs, attitudes and behaviours. Insight gained from this aids in transformative learning where trainees develop an action plan for further self-improvement and increased performance based on their own experiences. Lev Vygotsky described the zone of proximal development (ZPD) as a space between what a person knows (an action that can be performed easily) and what a person doesn't know (what is considered difficult). Vygotsky theorised that learning is most effective within this zone. Coaches facilitate effective learning by providing coachees with activities within the ZPD, which are neither too easy nor too challenging (this is a process called scaffolding).