Fixed-ratio (FR) schedules: in an FR schedule, reinforcement occurs each time a set
number of responses of a particular type are emitted.
Ratio Strain: the deterioration of responding from increasing an FR schedule too rapidly
is sometimes referred to as ratio strain.
The higher the ratio at which an individual is expected to perform, the more important it
is to approach it gradually through exposure to lower ratios. The optimal ratio value that
will maintain a high rate of response without producing ratio strain must be found by trial
FR Schedules, when introduced gradually, produce a high steady rate until
reinforcement, followed by post-reinforcement pause. The length of the post-
reinforcement pause depends on the value of the FR-the higher the value, the longer
the pause. FR schedules also produce high resistance to extinction.
Piece-rate pay: paying an industrial worker for a specified number of completed parts.
Variable-ratio (VR) schedule: the number of responses required to produce
reinforcement, changes unpredictably from one reinforcement to the next.
The number of responses required for each reinforcement in a VR schedule varies around
some mean value, and this value is specified in the designation of that particular VR
schedule. **Look at page 78 first parsgraph “salesperson” example**
VR, like FR, produces a high steady rate of responding. However, it also produces no (or
at least a very small) post-reinforcement pause.
Three additional difference between the effects of VR and FR schedules without
producing ratio strain, the values of VR that can maintain responding are somewhat
higher than FR, and VR produces a higher resistance to extinction than FR
schedules of the same value.
!Ratio schedules are used when one wants to generate a high rate of responding and can
monitor each response (since it is necessary to count the responses in order to know when
to deliver reinforcement on a ratio schedule). FR, is more commonly used than VR in
behavioural programs because it is simpler to administer.
!Ratio schedules have also been studied in discrete-trials procedures, such as in a task
designed to teach children with developmental disabilities to name pictures of objects.
!The procedure involves presenting a carefully designed sequence of trials in which the
teacher sometimes speaks the name of the picture for the child to imitate and sometimes
requires that the child name the picture correctly. Correct responses are reinforced with
praise (e.g. “good!”) and a treat; and children make more correct responses and learn to