Yankelevitz, R.L., Bullock, C.E. & Hackenberg, T.D. (2008).
Reinforcer accumulation in a token-reinforcement context with pigeons.
Journal of the Experimental Analysis of Behavior, 90, 283-299.
Four pigeons were exposed to a token-reinforcement procedure with
stimulus lights serving as tokens. Responses on one key (the
token-production key) produced tokens that could be exchanged
for food during an exchange period. Exchange periods could be produced
by satisfying a ratio requirement on a second key (the
exchange-production key). The exchange-production
key was available any time after one token had been produced,
permitting up to 12 tokens to accumulate prior to exchange.
Token accumulation, measured in terms of both frequency (percent
cycles with accumulation) and magnitude (mean number of
tokens accumulated), decreased as the token-production
ratio increased from 1 to 10 across conditions (with
exchange-production ratio held constant), and increased
as the exchange-production ratio increased from 1 to 250
across conditions (with token-production ratio held
constant). When tokens were removed, accumulation decreased
markedly compared to conditions with tokens and the same schedules.
These data show that token accumulation is an orderly function of
token-production and exchange-production schedules, and
they are broadly consistent with a unit-price model based on
local and global responses per reinforcer.
Key words: reinforcer accumulation, token reinforcement, unit price,
fixed-ratio schedules, key peck, pigeons