Which type of reinforcement focuses on motivating through gradual and less predictable rewards?

The focus on motivating behavior through gradual and less predictable rewards aligns with the concept of a variable ratio schedule. This type of reinforcement is characterized by providing rewards after an unpredictable number of responses, which can create a high and consistent level of engagement and motivation among individuals. The unpredictability of the reward system enhances the excitement and anticipation of receiving a reward, as individuals are uncertain when their effort will be reinforced. This method is often seen in scenarios such as gambling, where the chance of winning keeps individuals engaged.

In contrast, fixed interval schedules provide rewards after a set period, fixed ratio schedules reward after a specific number of responses, and continuous reinforcement offers rewards after every single response. These methods, while effective in their own right, do not embody the element of variability and unpredictability that significantly enhances motivation over time as seen in a variable ratio schedule.