Hs. Terrace et al., SERIAL-LEARNING WITH A WILD CARD BY PIGEONS (COLUMBA-LIVIA) - EFFECT OF LIST LENGTH, Journal of comparative psychology, 109(2), 1995, pp. 162-172
Pigeons (Columba livia) learned 3-, 4- or 5-item lists prior to subset
and wild card tests. On the latter, a novel item replaced I of the li
st items. Pigeons who learned 5-item lists responded accurately on all
subset pairs (AB, BC, and AC) and on all types of 3-item wild card tr
ials (WBC, AWC, and ABW). Pigeons who learned 4- and 5-item lists resp
onded at chance levels of accuracy on all subsets that did not contain
a start or an end item (BC, BD, and CD, respectively, on 4- and 5-ite
m subset tests). On wild card trials, they exceeded chance levels of p
erformance only when the wild card replaced the last item (ABCW and AB
CDW trials). Monkeys (Cebus apella) trained to produce a 5-item list p
erform accurately on all subsets and wild cards. (M. R. D'Amato and M.
Colombo, 1988, 1989). These differences provide strong evidence that
pigeons and monkeys form qualitatively different representations of li
sts containing four or more items.