Constraining response output on conjunctive fixed-ratio 1 fixed-time reinforcement schedules: Effects on the postreinforcement pause

Behavioural Processes, Elsevier

10 (1985) 249-264

249

CONSTRAINING RESPONSE OUTPUT ON CONJUNCTIVE FIXED-TIME REINFORCEMENT SCHEDULES: EFFECTS POSTREINFORCEMENT PAUSE

FIXED-RATIO ON THE

1

FLORENTE LOPEZ and CARLOS PEREIRA Universidad National AutGnoma de Me'xico, Maestrfa de Experimental de la Conducta, Apartado Postal 21-182, c. P. 04000, Msxico, D. F., MEXICO. (Accepted

16 February

Anslisis Coyoachn,

1984)

ABSTRACT response output on LBpez, F. and Pereira, C., 1985. Constraining Conjunctive Fixed-Ratio 1 Fixed-Time reinforcement schedules: effects on the postreinforcement pause. Behav. Processes 10: 249-264.

TWO experiments used response-restriction procedures in order to test the independence of the factors determining response rate and of the postreinforcement pause on the factors determining the size interval schedules. Responding was restricted by response-produced blackout or by retracting the lever. In Experiment 1 with a the blackout procedure reduced the Conjunctive FR 1 FT schedule, postreinforcement pause more than the lever-retraction procedure did, and both procedures produced shorter pauses than did the schedule without response restriction. In Experiment 2 the interreinforcement interval was also manipulated, and the size of the pause was an increasing function of the interreinforcement interval, but the rate of increase was lower than that produced by fixed interval schedules of comparable interval durations. The assumption of functional independence of the postreinforcement schedules is questioned pause and terminal rate in fixed interval since data suggest that pause reductions resulted from constraining variation in response number compared to equivalent periodic schedules in which response number was allowed to vary.

Postreinforcement Key Words: press, water reinforcement,

pause, rats.

periodic

lever

schedules,

INTRODUCTION On

fixed-interval

resr.onse

after

reinforcement. this by

schedule

a positively

reinforcement 1957;

Schneider,

0376-6357/85/$03.30

(FI)

the

lapse

The

typical

consists

reinforcement of

of

increasing occurs

pattern

In

0 1985 Elsevier

schedules, period

of

of

Dews,

1970,

addition,

Science

Publishers

1978;

the

size

first

results

observed pause

rate

a constant

the

time

responding

a postreinforcement or

(e.g.

1969).

a fixed

of

(PRP)

B.V. (Biomedical

under followed

responding

Ferster of

in

until

& Skinner,

the

PRP

Division)

is

an

250

increasing timing

function

processes

(Gibbon,

have

the

temporal

factors

length.

In

to

the

(if

such

any)

at

responses

alter

the

per

of

the

that

previous

yet

differ

the

fixed

Shull

the

IRI

response (1970) in

responding leading

to

may

manner

and

terminal

the

and

following

properties

of

responding,

size

PRP

functional schedules They

was

are

has

been

but

comparable

the

FI

functional

that

and

PRP

responding addition, probably these

FR) mean

also authors

PRP

and

(19711

(FT) affect

rate

the

rate

on

the

(1969).

fixed-interval

terminal

equivalent

and

for FI

Killeen

tandem

was

times:

support

and

and

PRP,

rate

Response

terminal

of of

upon

(3)

and

Additional

remains

has

FI an

rate

was rats;

having

response

effects

reinforcement

IRI;

increasing thus

a response

showed

in that

reported For

to

by

the

requirement determining with

and

function

suggesting

also

that

rate

those

of

produced

pigeons,

contradicts

example,

Lowe

schedules,

affected

involved

been

assumption.

under

be

The

rats

schedules.

with

may

(1)

FI the

pattern

mean

interresponse

Shull

schedules

independence

running

previous

by

the

on 1 FT

the

on

have

using

the

terminal

PRP

fixed-time

evidence

pigeons

the

the

provided

FI

Nevertheless,

rats

of

that

(Tan

responding,

by

schedules

(1970)

in

those that

may

FR

not

independent.

independence

fixed-ratio

by

determined

FI

Conj

isolated

of

to but

1 FT)

but

effects

of

response

in

differences

rate

as

FR

Morgan

effectively

such

IRIS

effective

time.

reported

diffe'rential

functionally

demonstrated

any

of

number

both

(Conj

whereas

response rate

compared

example,

the

suggestions:

the

The

at

response

by

(2)

that

pigeons

determined

PRP

in

interval,

from

schedules.

be

equivalent

For

effects

isolated

the

to

pause

the

FI

may

maintain

occur

using

this

with

as

the

particular

and

1 fixed-time

IRIS,

be

the

schedules

factors.

fixed-ratio

after

and

FI

remains

delivery,

associated

equivalent

effective

of

relationship

factors,

must

and

& Spencer,

determining

reinforcement,

under

must

occur

(IRI)

position

of

schedules

conjunctive

ones

this

question

important

reinforcement

moment

obtained

under

some

for

Harzem,

the

interval

temporal

for

Lowe, the

only

discrimination

account

1981;

other

reinforcement

PRPs

obtained

and

the

responsible

responding

Mean

as

to

temporal

However,

are

identify

interreinforcement

factors

so

invoked

1981).

whether

of

value,

& Killeen,

& Wearden,

order

FI

been

Hanson

1977;

Lowe

1979;

of

of

that size for the FT

while

Harzem

studying (1977)

the

size

terminal of

the

rate

PRP.

of

120-set

the

found

of

the of

In

reinforcement

size

the

iS PRP,

produced

since large

251

decrements

in

substantial

increases

observed In

under

another

(1979)

was

30-set

and

size

so

as

to

with

to

FI

for

1968,

The

authors

schedule and

the

responding

to

FI

in

Conj

FR

such

are

to

of of

of

on

by

the

FI

of

the in

of

response.

the

blackout

procedure & Schneider,

as

the

300-set PRP

between

PRP. FI

conditions,

this

the

the

it

1970,

number

of

schedule.

on

the

response

latter number

blackout

of

per

in

per

further

the

limited

can

be

not It

since

be is

is

blackout

an

open

mean

PRP,

If

the periodic

the

differential control 19613; Nunes

as

well

as

produced, as

the

schedules only of

by

Nunes

number

the

interval

question

whether

the

since

increases

limited

as

response-prevention

1 FT

maximum

than

of

be

procedure

the

greater

FR

such

1975). the

evaluated

usually

at

be

different

the

in

or

reported

directly

can

Con]

reinforcement in

length.

must

and

been

& Schneider, of

reductions

FI

results,

which

reinforcement

Finally,

should

the

of

responses

output

measure

(Neuringer

PRP

of

effect

upon

for

equivocal

favor

arise

number

& Frank,

contribution

the

terminal

distributions.

procedures

which

and

has

based

multimodal an

those

upon

whereas

reinforcement

or be

the

effect

been

in

PRP

this

symmetrical

schedules

size

responses

is

and

in

Staddon

have

either

interpretation

response

such

1971;

the

in

PRP.

low no

reports

may

of

the

which

specific

responses

conclusive

a decrease

However,

FI

respcnses

not

Problems

of

in

for

the

size,

is

if

skewed

PRP

increases.

the

size

decreased

interaction

FI of

each

Neurinqer

shortening

independence

unimodal

1979),

interval

by

in

an

Shull,

number

al.,

procedure

per

PRP

from

the

also

mean

the

First,

Secondly,

response

(1979)

(see

decreased

that

evidence

1 FT.

mean

effects.

number

the

shortening

1970;

schedules,

number

results),

schedules

distributions

value

effect

schedules.

ways:

assumes

range

affected

produce

(Morgan,

et

not

was

in

the

Unfortunately, which

PRP

mean was

functional

three

or

as

result

on

observed FT

after

output

in

size

different

ones

Crossman

reinforcement

a blackout in

the

IRI.

against

were

per

manipulated

and

the

by to

number

of

response

suggested

Altogether,

least

response

responses

imposing

compared

Alferink,

determination

of

reinforcement

could

the

Nunes,

lower

30-set

per

PRP,

was

similar

responses

accompanied

blackout

Although

the

the

whether

the

number by

responding of

pigeons,

in

300-set

the

of

size

determine

the

produce

increased. when

the

study

involved

FI

of

in

120-sec.

manipulated

The

rate

FI

attempted

schedules They

terminal

the

of

PI

the the et

al.

responses

size

divided

overall

252

response

reductions

important the

or

factor

constraints

involved

in

in

the

the

upper

observed

limit

decrement

is in

the

the

size

of

PRP. Two

experiments

various decreased

output

first

experiment

under

three

to

vary

and

in was

a blackout compared

under

conditions

standard

FI

1

If

IRI

is

the

schedules, 1 FT

the

the

value

one

contribution

the

combination

the

size

the

PRP

in

retraction

the

to

which two

response

function

of

on

and

one

complete

the

of

constraint

of of

in

PRP.

to

1 FT

was

free

by second

interval

response

The

FR

which

The

lever.

PRP

of of

reinforcement

the

in

the Conj

responding

others

per

relating

the

contribution

determinant of

and

per

the

to

and

effects

programming,

or

size

60-set

one

of

the

conditions:

of

determine

size

output

and

PRP

periodic

schedules.

EXPERIMENT

the

interval

restricted

of

to

procedures

the

standard

experiment

FR

presented

determines

different

as

responding means

are

response-prevention

the

the

same The

reinforcement.

PRP

of

are

PRP

two

analized

of

the

should

schedule effects

size

not with

of

the

the

different

responding

constrained

response-prevention in

of

be

present

on under

Conj

constrained responding

procedures

to

to

and the

size

experiment.

METHOD

Subjects Nine

male

individual

Wistar

cages

rats

and

with

food

permanently

rats

were

given

free

(90

to

100

days

old)

maintained

on

a 23-hr

available

in

their

access

to

water

for

operant

two

retractable

were

water cages.

for

25

housed

in

deprivation After

cycle

each

session,

min.

Apparatus A

standard

RG-004) right

equipped lever

was

experimental light

noise

with

retracted

conditions

bulbs

cue-light period.

chamber

provided located

A sound served

to

the

attenuating mask

the

proqrammed illumination

general

feeder

cup

enclosure,

extraneous

with

levers

throughout were

above

studies

sounds.

rats and

the

for

Model

a feeder and

experiment, for

(BRS

left

the

signalled

lever.

The

Two and

chamber, the

a ventilating Solid-state

cup. the

6-w a

reinforcement fan,

and

programming

white

253

equipment

controlled

recorded

on

all

experimental

electro-mechanical

events,

counters

and

and

data

were

a print-out

counter.

Procedure After

shaping,

reinforcement experiment Conj

FR

all

proper 1 FT

following

began.

60-set

60-set

timed

All

CONDITION.

conditions

to

a continuous

sessions.

involved

schedule,

If

out,

the

it

least

first

was

one

Then,

the

but

response

BLACKOUT

CONDITION. case,

but

the

interval

timed

out

completely

LEVER-OUT

same

the basic

differed

in

the

CONDITION. a response in

occurred

after

an

immediately

to

the

pulses

per

until

set

the

per

delivery

of

Subjects and

Blackout

and

CJ-8

(subject

the

a

cup

on.

sent first

week

36th

A-4,

through

At

as

before

the

in

chamber

to

the

the the

until

0.2

and

ml

counter session

it

was

available.

of

tap

water

and off

3-set

This

first

it

case

valve,

counter

the

each

which

house-lights the

The

unless

remained

occurred.

A-6,

and

A-7

whereas to

CJ-8

died

a respiratory

after

in

60-set

it

and

was the

reinforcement at

a rate

value was

was reset.

terminating

of

10

printed Seven by

the

reinforcer.

conditions,

condition

out,

of

every

interval.

lever

of

end

conducted,

A-5,

of

the

print-out

response

delivered

the

lever

the

the

exposed

changed

interval

delivered

a solenoid

with

period

were

the

consisted

period

were

within

timed

were

second

the

an

occurring

was

retracted

and

3-set

the

the

every

within

after

darkened

interval

feeder

reinforcement

sessions

was

response

occurred

interval

cue-lamp

period,

occurred

Reinforcement

reinforcement

by

reinforcement

first

reinforced

cases

accompanied

occurred

delivery.

response

delivered

administered

reinforced.

Reinforcement

provided

all

was

response

immediately

previous

during

exposed

consecutive

A reinforcer

at

reinforcement

the

were

five

reinforcement

whenever

interval.

were

for

arrangements:

NO-CHANGE

In

animals

schedule

and

the

was

were

subjects

No-Change

omitted

a predetermined

exposed

and

CJ-4,

from

the

CJ-5,

Lever-Out

disease

number

to

by the of

the

No-Change CJ-6,

CJ-7,

conditions 20th

report). sessions

session Conditions

approximately

of

254

representing

the

experimental

literature.

conditions Table

1.

TABLE

1

and

number

number

of

of

sessions

to

steady-state

Specific

details

sessions

per

about

condition

observed

in

the

order

are

presented

the

of in

Number of sessions per condition, mean PRP CM), standard deviation and relative PRP (R) from data collected over the last five (SD), sessions of each condition are presented for each subject for Experiment 1. Relative PRP was obtained by dividing the mean PRP by the interreinforcement interval. SUBJECT

M

SD

R

A-4

CONDITION No-Change Blackout No-Change

SESSIONS 45 35 20

33.8 18.5 34.4

12.6 8.1 12.1

0.56 0.31 0.57

A-5

No-Change Blackout No-Change

45 35 20

37.1 18.0 43.4

9.9 7.6 15.9

0.62 0.30 0.72

A-6

Blackout No-Change Blackout

45 35 20

22.5 35.2 27.0

12.0 15.1 12..7

0.37 0.59 0.45

A-?

Blackout No-Change Blackout

45 35 25

1.5.0 29.8 23.3

7.0 12.7 6.7

0.25 0.50 0.39

CJ-4

No-Change Lever-Out No-Change

50 30, 20

23.4 10.1 21.6

18.4 5.4 20.5

0.39 0.17 0.36

CJ-5

No-Change Lever-Out No-Change

40 30 20

52.8 50.5 50.1

13.1 13.4 13.0

0.88 0.84 0.83

CJ-4

No-Change Lever-Out No-Change

40 30 20

48.3 31.2 21.4

14.1 13.5 10.6

0.60 0.52 0.36

CJ-7

Lever-Out No-Change Lever-Out

40 40 30

22.8 35.9 37.3

10.7 12.9 21.6

0.38 0.60 0.62

Results All

analyses

sessions occurring

on

before

presents

PRP

relative

pause

the

were

each

based

upon

data

the

first

reinforcement

in

as

means

(M),

deviations

durations

(R)

subject

during

for

data

each

collected

condition

standard

obtained

by

and each

dividing

the

excluded session. (SD), the

mean

last

Table

differences

were

observed

on

these

measures

for

1

and PRP

IRI. Clear

five

responding

all

by

255

subjects

exposed

Blackout

condition

condition

for

deviation. those

contrast,

no

exposed

between so

subject

into bin

is the

(broken

lines

relative

by

average

and

No-Change

the

Blackout

and

more

the

other

the

obtained

The

general

was

form

of

conditions, the

that

the

reinforcement average

of

10

reinforcement

variation

in

responding of

the

second

half

exceptions and

cases

of

the

largely

produced

to which

produced

the

interval

restricted bitonic

each

of

to

of

exposed

varied

in

the

each

with

Blackout

in

Fig.

short

l),

pauses

condition. for

to

of

sorted

PRPs

obtained

graphs

found

rows

were

resulting

No-Change

were

of

obtain

results

On

the

the

graphs

No-Change in

greately

redetermined

No-Change

Fig.

11:

between

values

and

only

sixth

one

did

from

from

30).

1 to

made

between

was

observed

one

per

not

were to

distributions

per

condition!

there

On

this

the and

around subjects

basis,

those

in

For

those

7th

in

bin), the

cases

reinforcement, centered

in

which

in

9 out the

which

example,

was

lying

an in

which

For

condition

the

an

to

conditions

in

were

No-Change

reinforcement.

compared. one

the

distributions

the

other per

reinforcement

No-Change

(centered to

two

However,

in

variation

the

the

response

session.

bitonic

belonging

conditions was

be

number

in

to

The

number

reinforcement

was

must

restricted

them

Lever-Out

responding

range

occassions

9 of

effect,

the per

response

was

13

in

in

distribution.

considerable

comparison

of

as

exposed

the

lower

produced

about

(the

additional

did

for

pauses

so

rows

subjects

two

and

the

ones

responses

with

condition,

upper

a greater

the

original

after

differences

number

of

subjects

two

distributions

between

latter

pattern

than

(the

the

PRPS

differences

both

difference

for

negligible

distributions

subjects.

those

with

the

and of

the

(the

clearcut

conditions

recover

standard

conditions.

were

to

No-Change

found

Lever-Out IRIS

The

the

were

Individual

number

distributions

Lever-Out

One

the for

distributions

each,

produced

and

always

and

obtained

individual

With

condition

in

differences

redetermined

followed

distributions

subjects

total

for

no

as

frequency

6-set

conditions

hand,

did

conditions). of

measures.

peaked

than well

as

contribution

represent

closely

the

values PRP

No-Change and

conditions.

discarded.

frequencies

distributions

the

relative

bins

divided

Blackout

systematic

possible

experimental

consecutive was

to

its

1 shows

particular

relative

scheduled

that

and

shorter

and

distributions Fig.

No-Change

mean

subjects

cases,

IRI

the

produced

the

In

Differences all

to

first

in the with

the

No-Change which of

11

half

256

0.6 0.4

0.6

I

A-5

A-4

A-7

A-6

a! 0 A I

1

0.6 0.4.

CJ-4

CJ-5

CJ-7

4 ::

7

Li

I

l

z

e, m

3

T

6

9

M

I

3

E

6

9

6

I

3

N

6

0

S

frequency distributions of the PRP for Experiment Fig. 1. Relative 1. Individual PRPs collected during the last five sessions for each subject were sorted into 6-set bins and divided by the total number considered for each subject. Broken lines represent redetermined distributions of particular experimental conditions.

of

the

interval

(around

condition

generally

Lever-Out

condition.

between even

the

though

condition

condition

hid

short

pauses

and

failure

No-Change

the

2nd

in fact

(except

in

or

more

Therefore,

No-Change the

the

produced

the

3rd

bin),

peaked there

two

was

to

recover

the

animals

exposed

the

subject

substantial

response-prevention

the that

although

Lever-Out CJ-5).

the

distributions

distributions to

the

condition

Blackout

than

did

difference procedures for

the

Lever-Out also

produced

the

251

EXPERIMENT

In with

2

order the

to

IRI,

observe the

reinforcement

possible

temporal

schedule

was

function

relating

PRP

function

produced

by

to FI

interactions

of

reduced

requirement

of

a constrained

manipulated

in

Experiment

interval

size

can

schedules

with

equivalent

then

responding Conj

2.

be

FR

The

compared

1 FT

obtained with

the

temporal

requirements.

METHOD

Subjects Seven

male

Wistar

rats

individual

cages

throughout

the

given

access

to

in

previous

free

and

(three

to

maintained

on

At

experiment. water

the

for

four a 23-hr

end

25

months

of

old)

water each

were

housed

deprivation

session

in

cycle

animals

were

min.

Apparatus Same

as

the

experiment.

Procedure After

reinforcement were

and

remaining

were

as

to

1 FT

t-set

to

exposed

to

consecutive

FR

1 FT

FI

CJ-1,

a continuous

sessions.

three

Then,

t-see

reinforcement

schedules,

schedules.

Experimental

conditions

the

previously

and

the

next

the

lever

end

of

the

CJ-3

within

interval

the

lever

interval

was

initiated

If

available. timed

out,

remained

available.

the

interval. out

until

response was

fixed-time

under

response

Responses

completely

the

darkened

after

immediate were

and

on

15,

Rats 60,

and

MU-7, llO-set

MU-8,

MU-g,

reinforcement

and

MU-12

were

schedules.

and

the the

used:

lever 15,

llO-sec.

FI-GROUP.

the

delivery,

house-light

occurred

values

Conj

was a

if

reinforcement with

reinforcement Three

interval

timed

the

studied

Reinforcement

specified

retracted

interval

were

schedules. the

occurred

before and

and

CJ-2,

reinforcement

at

chamber

FI

five

Conj

subjects

Rats

occurring

and

were

follows:

delivered had

for

exposed

CONJ-GROUP. FR

animals

schedule

animals the

all

shaping,

exposed

to

Reinforcement

60

258

was

delivered

timed

TABLE

for

the

first

response

after

the

fixed

interval

out

2

Number of sessions for each condition, mean PRP (M), standard deviation (SD), and relative PRP (R) from data collected over the last five sessions of each condition are presented for each subject for Experiment 2. Relative PRP was obtained by dividing the mean PRP by the interreinforcement interval CONJ-GROUP CONDITION

SUBJECT

CJ-1

CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ CONJ

CJ-2

CJ-3

FR FR FR FR FR FR FR FR FR FR FR FR FR FR FR

SESSIONS 15

1 FT 1 FT

1 FT 1 1 1 1 1 1 1 1 1 1 1

FT FT FT FT FT

FT FT FT FT FT FT

I FT

25 25 30 25 25 25 25 30 25 25 25 25 30 25 25

60 110 60 15 15 60 110 60 15 15 60 110 60 15

M

SD

R

8.2 18.0 20.3 15.7 9.5 9.6 14.8 20.8 17.4 9.9 7.8 18.3 21.5 14.2 10.5

3.? 8.8 11.4 7.4 5.1 3.9 5.2 6.8 6.2 4.2 3.1 10.1 7.8 5.8 4.1

0.55 0.28 0.31 0.24 0.63 0.54 0.23 0.32 0.27 0.66 0.52 0.28 0.33 0.22 0.70

M

SD

R

8.8 19.8 27.1 68.4 9.9 35.0 33.7 53.5 5.7 37.6 53.9 8.1

3.2 9.5 17.5 19.1 2.3 11.8 12.2 21.6 2.9 11.8 22.4 3.4

0.59 0.33 0.25 0.62 0.66 0.58 0.56 0.49 0.38 0.63 0.49 0.54

FI-GROUP SUBJECT

CONDITION FI FI FI FI FI FI FI FI FI FI FI FI

MU-7

MU-8

MU-9

MU-12

to

accompanied reinforcement of

the

were

a

of after

a

groups cup

3-set

period

PRPs seven

the

both

feeder

cue-lamp

individual

conducted

delivery changed

for the

by

28 20 25 25 24 20 28 22 19 27 15 17

15 60 110 110 15 60 60 110 15 60 110 15

Reinforcement delivered

SESSIONS

36th

with

on.

As

was

printed

days

per

reinforcer.

predetermined

consisted

through

in

the the

0.2

chamber

previous

during

week, For number

of

a solenoid

each the of

ml

of

tap

and

it

liqhts

off

and

the

the

size

experiment,

reinforcement. session Conj-Group sessions,

water

valve,

Sessions

terminating

bv

conditions whereas

was

for

the were

the

259

FI-Group

a minimum

terminated

when

within

of

or

10%

order

condition

each

the

decreasing

the

of

of

in

conditions

for

sessions the

overall

trends

of

15

each

was

mean

mean

PRPs for

terminal as

required, in

those

rates

well

as

the

last

and

observed.

number

a condition

five

sessions were

the

and

of

was

sessions no

fell

increasing

Table

sessions

2 shows in

each

subject.

_ 15

60

110

INTERVAL

VALUE

Fig. 2. The mean PRP as a function of the temporal requirement for Experiment 2. Broken lines connect the mean PRPs for the last five sessions on each condition for the subjects exposed to FI schedules. Continuous lines connect mean PRPs on each condition for the subjects exposed to constrained Conj FR 1 FT schedules; crosses represent redetermined values for the Conj schedule. Results All sessions collected as

means

each

of

broken

each

CM),

of lines

relative

groups

were

before

subject

function

and

analyses

mean

based

in

PRPs PRP

collected

condition

for

reinforcement.

each

for

data

the

first

standard

the

upon

deviation

at

value

the

PRP

Both

shortest as

the

and Table

and

is

relative

PRP in for

interval temporal

last

produced (15-set), parameter

five

data

2 presents

lines

qroups

the

excluded

presented

(continuous

FI-Group).

increased

subject

(SD),

Mean

group.

interval the

each

during

PRP (R)

Fig. the

2 as

a

Conj-Group,

similar and

data

for

in

increased.

mean both

260

I

0.6

z

FRl

FT15

FRl

fT60

FRl

F TflO

0.6

w

t

0.6

P

I

Fl60

0

3

6

9

3

FI 110

6

9

3

9

6

Relative frequency distributions of the PRP for Experiment Fig. 3. PRPs collected during the last five sessions for each 2. Individual for each interval value. subject were sorted into ten bins Discontinuous lines represent redetermined distributions for the Conj-Group. the

However,

As

FI-Group. shorter

PRPs

llO-set)

rate

in

than

collected contribution

of

increase all

a result, the

did

two

the

within

0.5

of

this

was

higher

of

for the

subject

in

the

interval,

to

the

size

in

and

FI-Group

so of

the

produced (60

requirement

scheduled delay

the

Conj-Group

Reinforcements

the

additional

in

temporal

FI-Group. set

higher

subjects

that

the

PRP

for

each

were

the was

negligible. Fig. subject

3 shows in

the

the Conj

relative and

FI

frequency groups.

distributions

Relative

frequency

distributions

261

were

determined

with

bin

#lO

temporal each

by

the

two

groups

for

the

Conj-Group,

shorter

bins

the

as

the of

the

In

different

temporal

requirement

increased, In

total

at

number

the

for

of

pauses

for

redetermined

two

ways:

First,

around no

FI-Group.

the

Second,

Conj-Group

displayed

with

for

whereas

the

for

FI-Group

each,

the

centered

increased,

associated

t/l0

distributions

least

distributions

pattern

of

represent

observed

contrast,

bins

exceeding

distributions

was

the

into PRPs

general,

in

PRP

type

of

Conj-Group

relative

this

peaked.

by

the

values.

clearly

distribution

interval

in

pauses

number

dividing

particular

shift

more

consistent

the

lines

were

interval

become

and

Broken for

consistent

individual

containing

requirement,

subject.

distributions

as

sorting

also

no

changes

in

the

value.

DISCUSSION

In

Experiment

responding shorter

mean

free

vary.

to

responding and

the

more

1,

was

PRPs

differed changes

the

In

the

the

in

second to

than

studies Lowe

(i.e.

and

compared

on

those

that

effects

the

due for

to

on all

between

one

of

to

produce

mean

was

prevent PRP

(Table

1)

1) were

(Fig. condition

than

were

PRPs

the

the PRP the

Harzem,

may

the

by

requirements Conj-Group.

mean

PRPs

& Spencer,

1979; MU-T,

subjert

suqqest

the

the

they

are

effects

of

of

first

subjects fell

Third,

distributions

FI

by

similar in

was

other

conditions,

observed

FR

as

temporal

in

provided

were

Conj

increase

comparable

First,

produced

of

in increased

reported

Lowe,

of

retraction

PRP

rate

Conj-Group,

order

temporal

mean

with

data

lever

reinforcement

increase

reasons. PRP

Fourth,

the

the

the

in

and

per the

1981;

the

mean

produced

and,

in

the

higher

two

rates

several

the

values;

the

to

Blackout

schedules

Although

Second,

those

which

responding

distributions

However, FI

& Killeen,

restriction

differences

when

in

the

conditions,

by

obtained

than

in

tended

utilized

blackout to

increased.

those

values

both

these

Hanson

marked

pause under

responding

to

in

schedule

decrease

relative

1981).

experiment. FI-Group

procedures

produced

improbable

response

same

two

Wearden,

confounding highly

and

the

the

the

schedule

reinforcement

did

experiment,

value

requirements

6O-set

per

condition.

Under

that

1 FT one

consistent

restrict

interval

FR to

that

the

and

schedules.

lower

in

Lever-Out

combined 1 FT

than

However,

pronounced

under

a Conj

restricted

of the

at

in

there the

the

hiqher

two

FI-Group

are crroups fall

262

within

the

range

schedules

of

(i.e.

obtained

Hanson

results

in

Killeen,

1981;

introduced

by

L

other

experiments

Lowe,

Harzem,

with

FI

Spencer,

L

1979). The

specific

procedures

can

However,

it

determined

suggest

that

report

introduced

but

of

effect

Both

values

when Nunes

decreases

responses the

size

of

the

et

al.

as

a result

PRP

the

1970;

Shull,

reinforcement. in

per

number

of

In

Nunes

the

FI,

that

no

et

al.

rate

the with

(1979)

FI

by

15

sec.

the

llO-sec.

suggest

that

the

incompatible

mere

number

the

standard

number

of of

1970; in

involved

schedules,

value

of

(Shull,

reduction

factor

mean

the

determining

schedules

mean

2 of mean

account

the

FI

the

Experiment

and

factors

of

(300

between

important

differ

number

Standard

from

in

FI

was

report

the

However,

60

means PRP

produced

produced

an

IRI, of

In

requirement

present

by

of

the

in

the

Conj

FR

responses

the

PRP

1971).

the

reinforcement;

responses

the

schedules

limit

set).

FI-Group

a reduced

1970,

upon

(30

number

mean

a long

the

interaction

altering

periodic

imposed

be

produce

without

various

invariance

not

Compared

PRP.

schedules

the

independence

may

of

responses

an and

responses

reinforcement

similar

of

1972).

FT

These

and

on

were

and with

mean

reduced

one

of

procedural

a result,

were

is

evidence

agreement

and

PRPs

Conj

change

Such

study,

decreased

temporal

Standard

changes

close

was

As

(1970)

procedures

of

that

requirements

terminal

shortening

in

In

Shull

interval.

stimulus

schedules

mean

the

of

(Morgan,

the

Witty,

number

and

of

and

FI

a short

(1979)

hand, in

duration.

mainly

a stimulus

spite

are

response.

L

Guilkey,

in

on

reinforcement

Shull,

hand,

Conj-Group

temporal

assumption

mere

responses

when

an

the

of

shorter

the

per

with

1 FT

the

consistently

Conj-Group

to

no

report,

similar

whereas

per

number

each

one

not

pause

was

similar or

(1979).

in

after

the

PRP

response-prevention

results al.

On

within

of

other

et

prevention

to the

remains

whether

the

present

the

had

PRP

result

Nunes

in

responding.

response

the

response

contributors

of

reinforcement

as

present

the

of

the On

imposed

decreased

PRPs

by

per

of

effects not

differences,

responses

in

first

them.

reported

a blackout

PRP

the

by

subject those

set),

size

the

shortening

regardless the

are

as

the

reduction

the

with

ignored

that

schedules

introduced

the

be

the

that

1 FT

this

not

appears by

reported FR

changes

is

of

Conj

in

the

responses

FR

1 FT,

imposed

upon

thus

relatively

reinforcement

to

procedure,

the

the

degree

from and

FT

schedules

maximum large

number variations

reinforcement possible

of

reinforcement

range

are of

are of in possible

263

variation response present which

decreases

as

the

size

increases.

In

the

constrained

report,

no

variation

effect

on

the

no

wide

range

have

been

of

possible

that

responses factor that

to

from

the

reinforcement with

number

of

ones

such

FR

in

range

possible

which

pause

from

in

is

interval

regardless

of

to the

reductions

so

would

as

to

interval, number

it

is

number

of

important

This

constrained

the

in

a relatively

the

the

of

cases

variation,

PRP.

each

schedule the

for

of

the

after

allow

variation

of

is

1 FT that

reinforcement

schedule

result,

imposed

Given

reported

shortening

responses

should

blackout Conj

the

to

the

a periodic

normal

been

narrow

constraining

whenever

than

has

the

allowed.

whereas

tend

associated

constant

is

PRP

variation,

reported

of

mean

produce

shorter

of

a PRPs

responses

allowed. At that

any the

amount

rate,

the

relation

of

by

strongly

suggest

schedules

Lowe

are in

allowed

and

and

the

the

rate

IRI

to

of

Nunes

and

PRP

PRP,

the

parameters

was

conducted

and

these

proposed

in

in

those

(1979), interval

that

rate

are

with

al.

size

effects

of

change

important

most

of

the

per

alonq et

the

results

upon

responses

Given

in

2 suggest

depends

results, and

independent.

distribution

Experiment

size

number

present

functionally

1 and

interval

(1977),

response

pause

relating of

Experiment

in

Harzem

that

not

the

clarification temporal

PRP

Therefore,

obtained

function

from

variation

reinforcement.

observed

data

between

the

were in

the

for

the

models

of

control.

AKNOWLEDGEMENTS

This School

research of

the

AutBnoma

de

Reid

for

his

and

Arturo

Department The

Msxico. valuable

Bouzas

of

for

under

authors

sponsorship Dniversidad

greatfully

assistance his

the

Psychology,

oportune

in

the

of

aknowledge writing

comments

and

of

the

Graduate

National Alliston the

K.

manuscript

advice.

REFERENCES

The theory of fixed-interval respondinq. In: W. N. Dews, P.B., 1970. The Theory of Reinforcement Schedules. Schoenfeld (Editor), Appleton-Century-Crofts, New York, pp. 43-61. Studies of responding under fixed-interval Dews, P.B., 1978. schedules of reinforcement: II. The scalloped pattern Of the J. Exp. Anal. Behav., 29: 67-75. cumulative record. Ferster, C.B. and Skinner, B.F., 1957. Schedules of Reinforcement. Appleton-Century-Crofts, New York, 739 pp. Scalar expectancy theory and Weber's law in animal Gibbon, J.. 1977.

264

timing. Psychol. Rev., 84: 279-325. Hanson, S.J. and Killeen, P.R., 1981. Measurement and modeling of behavior under fixed-interval schedules of reinforcement. J. Exp Psychol. (Anim. Behav.), 7: 129-139. Killeen, P., frequency and contingency as 1969. Reinforcement factors in fixed-ratio behavior. J. Exp. Anal. Behav., 12: 391-395. Lowe, C.F. and Harzem, P., 1977. Species differences in temporal control of behavior. J. Exp. Anal. Behav., 28: 189-201. Lowe, C-F., Harzem, P. and Spencer, P.T., 1979. Temporal control 31: of behavior and the power law. J. Exp. Anal. Behav., 333-343. Lowe, C.F. and Wearden, J.H., 1981. Weber's law and the fixed-interval postreinforcement pause. Behav. Anal. Lett., 1: 27-32. Morgan, M.J., Fixed-interval schedules and delay of 1970. reinforcement. Q. J. Exp. Psycho., 11: 663-673. Neuringer, A.J. and Schneider, B.A., 1968. Separatinq the effects of interreinforcement time and number of interreinforcement responses. J. Exp. Anal. Behav., 11: 661-667. Nunes, D.L., Alferink, L.A. and Crossman, E.K., 1979. The effect of number of responses on the postreinforcement pause in fixed-interval schedules. J. Exp. Anal. Behav., 31: 253-257. Schneider, B.A., 1969. A two-state analysis of fixed-interval 12: 677-687. responding in the pigeon. J. Exp. Anal. Behav., The response-reinforcement dependency in Shull, R.L., 1970. fixed-interval schedules of reinforcement. J. Exp. Anal. Behav., 14: 55-60. Postreinforcement pause duration on Shull, R.L., 1971. fixed-interval and fixed-time schedules of food reinforcement. Psychon. Sci., 23: 77-78. Shull, R-L., Guilkey, M. and Witty, W., 1972. Changing the response unit from a single peck to a fixed number of pecks in fixed-interval schedules. J. Exp. Anal. Behav., 17: 193-200. The role of the peck-food Staddon, J.E.R. and Frank, J.A., 1975. contingency on fixed-interval schedules. J. Exp. Anal. Behav., 23: 17-23.