On the first day of class professor Wallace tells her geography students that pop quizzes will be given at unpredictable times throughout the semester. Clearly, studying for professor Wallace's surprise quizzes will be reinforced on a schedule.
variable-interval

variable interval

Explanation:

A variable interval schedule (VI) is a type of operant conditioning reinforcement schedule in which reinforcement is given to a response after specific amount of time has passed (an unpredictable amount of time), but this amount of time is on a changing/variable schedule.

Variable Interval Schedule

Explanation: Variable Interval Schedule mostly uses the algorithm or principle of operant conditioning, it is an associative learning where by consequences (result) changes the behavior of an individual. A schedule is the frequency of reinforcement. The passage of time, the rewards (reinforcer) and variable which is the behavior. Variable Interval Schedule explains the rewards gotten after a period of time following a particular behavioural actions carried out.

it´s related to his charming character.

beauty is not everything, although we can joke that girls only care about the physical or material aspect, the truth is that a real woman looks at more important things, besides intelligence and personality, there are other attitudes that make irresistible to men who are 'unattractive'.

for example develop your sense of humor.