Alex the gray parrot was no ordinary bird. The subject of a thirty-year investigation into avian cognition, by the time he died in 2007, numerous scientific publications had pointed to Alex as proof that a bird's mathematical abilities could be on par with — and even exceed — those of chimps and other non-human primates.
Now, the results of the Alex's last experiment have been published — and the findings are more compelling than ever.
Alex's mathematical prowess has been well documented. The parrot could quantify sets of up to eight items; identify and correctly order Arabic numerals from 1—8; and even sum two sets of objects presented one after the other, so long as their sum total was less than or equal to six.
But an article published in the latest issue of Animal Cognition by animal psychologist Irene Pepperberg — who studied and cared for Alex for over three decades — suggests that Alex was capable of even more impressive mathematical feats.
The study was designed to further examine two of Alex's cognitive abilities. The first involved adding Arabic numerals, the second required Alex to sum three sets of objects (as opposed to two, as in previous studies) presented one after the other. In this second experiment, objects were shown to Alex and immediately hidden under a cup — in other words, it was on Alex to pay attention to the items presented to him, remember their quantities, perform the summation, and then vocally describe the exact total quantity. (The experiment was similar to the one seen in the clip shown here, only Alex was shown three quantities instead of two.)
In the Arabic numeral addition task, Alex indicated the correct sum 9 out of 12 times. In the three-set, sequential addition test, Alex squawked the correct answer 8 out of 10 times.
Unfortunately, Alex was only able to complete one round of each task before he died — a fact that obviously calls the validity of these findings into question. Pepperberg acknowledges this in the paper, but notes that Alex's accuracy was, in fact, statistically significant — due especially to the fact that the tasks were new to him; i.e. his performance could not be chalked up to practice structured around those tasks, specifically. Adapting and responding to novel situations was not uncommon for Alex, who would often combine words from his extensive vocabulary to come up with descriptions for objects he'd never seen before.
The experiment serves to reinforce Alex's standing as one of only two non-humans that have demonstrated an ability to represent the value of a summed set. The other animal to do so was a chimp named Sheba — who, it bears mentioning, could only sum sets to a total of four, compared to Alex's six.
"I wish that Alex had lived longer and I think this is an important study because it showed what he could do and where he was going," Pepperberg told Nature News.
"These brains can do, if not exactly what an adult human can do, really advanced behaviour that nobody expected them to be capable of."
Top image via.