4.1.4 – (Properties of reinforcement, including primary and secondary reinforcement and) schedules of reinforcement. 

Continuous reinforcement – a behaviour is reinforced every time it occurs

Partial reinforcement – a behaviour is reinforced sometimes, but not every time it occurs.

Schedules of partial reinforcement

Fixed Variable
Interval First instance of behaviour is
rewarded after a set period of
time.
First instance of behaviour is rewarded
after a set period of time, but the set period
changes every time.
Ratio Behaviour is reinforced after a
specified number of times shown.
Behaviour is reinforced after a set number
of times, but this number of times changes
every time.