JCP Sept 2018

Pigeons (Columba livia) Learn a Four-Item List by Trial and Error
Damian Scarf, Melissa Johnston, and Michael Colombo

Very cool article, and some of us should find this interesting. Learning lists can be hard for animals, and "usually" requires training them slowly and in increasing length. So, first train the arbitrary A-B sequence, then A-B-C, then A-B-C-D. This works well. But, to just throw ABCD up there and train it is hard, because there are 24 possible sequences, and most are wrong, so learning takes forever. Scarf et al. split pigeons up into those who were trained on a bunch of two item lists, then three item lists, then four item lists. Other pigeons just learned to do a four item list. On new problems (new lists) those with the "scaffolded" training did better, suggesting a kind of learning set for serial list problems. It's a bit of a complicated design, but if anyone was interested it would make an interesting monkey study. In addition, Washburn & Rumbaugh (1991) and subsequent studies on numeral lists probably relates here in interesting ways. So, for those into that paper, check this one out.

Bertamini, M., Guest, M., Vallortigara, G., Rugani, R., & Regolin, L. (2018). The effect of clustering on perceived quantity in humans (Homo sapiens) and in chicks (Gallus gallus). Journal of Comparative Psychology, 132(3), 280-293.

This one interested me because I have done some of the illusions and perception studies. Also very relevant to Kristin who needs to read it given some of our ongoing studies. The basic idea was to train people and chicks to learn (without instruction) to choose more or choose less dots, when on all trials dots not only varied in numerosity but also in clustering. Both species learn, of course, but then they get trials where numerosity or clustering are at odds (i.e., your choices illustrate which property you were probably using while learning). Humans used number. No surprise. Chicks were claimed to also do so in some cases, but to use clustering in others. Was kind of hard to know exactly what to make of some results, although I think the take-home message is that there was somewhat limited similarity across species.

Ebel, S. J., & Call, J. (2018). The
interplay of prior experience and motivation in great ape
problem-solving (Gorilla gorilla, Pan paniscus, Pan troglodytes, and
Pongo abelii). *Journal of Comparative Psychology, 132*(3), 294-305.

The idea here is pretty simple. Some apes just get the chance to mess around with a new apparatus before it does anything interesting. Others do not. Then, it gets baited in a way that requires a combination of actions to get reward. Those with prior experience just messing with it solve the novel problem quicker. So, they seem to form some sense of the basics, and then use those later when it matters, even though they had no way to know what kind of actual test was coming.

Two other papers that might be of interest. One is a summary of old and new research on pointing behavior in animals, with LRC friend Dave Leavens on it:

Krause, M. A., Udell, M. A. R., Leavens, D. A., & Skopos, L. (2018). Animal pointing: Changing trends and findings from 30 years of research. *Journal of Comparative Psychology, 132*(3), 326-345.

The other is about lemur problem solving. Basically, lemurs could learn to use a stick to get a reward, and then later tended to choose the better tool to solve a task. The authors concluded that although lemurs may not use tools in the wild, they may have the capacity to understand some basic tool functionality.

Kittler, K., Kappeler, P. M., & Fichtel, C. (2018). Instrumental problem-solving abilities in three lemur species (Microcebus murinus, Varecia variegata, and Lemur catta). *Journal of Comparative Psychology, 132*(3), 306-314.