During a prior study, Addessi even found that capuchins could indicate their food preferences based on token values, so a coveted Cheerio was worth more tokens than two pieces of Parmesan cheese. The results indicate the monkeys can reason about symbols.
James Anderson, a senior lecturer in the University of Stirling's Psychology Department, agrees with the new findings.
"Capuchins are renowned for their problem-solving abilities, so now the question is whether other species of monkeys can also show the same ability," he told Discovery News.
Michael Beran, a senior research scientist at Georgia State University's Language Research Center, told Discovery News, "It is important to see that smaller-brained primates can use symbols in this way and benefit from them the way that chimpanzees and humans do."
"Of course, as the authors noted, this does not mean the monkeys are as good as humans," Baren added, "but their data do support the idea of continuity across multiple species."