Data from: Stimulus dependent emergence of understanding analogical relations in budgerigars

The ability for analogical reasoning, such as understanding that the
relationship between two items is similar to the relationship between two
other items, has long been considered to be unique to humans. Whether and
to what extent non-human animals can recognize such relational analogies
is still debated. We tested such abilities in two groups of budgerigars
with a diverse set of item categories in which the figures of the stimuli
were quite different in nature (size, color, shape, geometric type, and
number). Budgerigars trained to discriminate two identical figures from
the same two figures differing in size, generalized the discrimination to
test stimuli belonging to the novel categories, demonstrating the
spontaneous use of analogical relations. In contrast, budgerigars trained
to discriminate two circles that were either the same or different in
color seemed to generalize to novel stimuli by perceptual rather than
conceptual similarity. The results thus demonstrate the spontaneous
emergence of perceiving analogical relations in budgerigars of a nature
beyond that demonstrated in previous studies of non-primate species.
However, the results also show that whether budgerigars generalize a
relationship by perceptual or conceptual similarity seems dependent on the
nature of the training stimuli.