AR Philosophy > Morality of AR > Speciesism - Index
Individual primates display variation in general intelligence
Public release date: 16-Jun-2009
Researchers demonstrate differing cognitive abilities
within a single primate species
The study, published this week in the journal PLoS One, is the first to examine differences of broad cognitive ability in primates within a single species. Previous studies of general intelligence in primates primarily concerned variation between species.
The research was led by Konika Banerjee, a research assistant in the Department of Psychology at Harvard University. Banerjee's co-authors are Marc Hauser, professor of psychology, and James J. Lee all of Harvard, along with Christopher Chabris of Union College, Fritz Tsao of Hillsdale College, and Valen Johnson of the University of Texas Medical School at Houston.
"We found that there was substantial individual variation in performance on these tasks," says Banerjee. "A significant proportion of that variation can actually be accounted for by something that looks very similar to the general intelligence, or 'g' factor, in humans. It appears to be the case that tamarins have something very similar to our general intelligence."
General intelligence, or "g," refers to the positive correlation of an individual's performance on various subtasks within an intelligence test. Banerjee and her colleagues found that "g" accounted for 20 percent of the monkeys' performance on the tasks in the study. The remaining 80 percent of the variation in performance was due to task-specific or environmental circumstances in testing the monkeys.
While not a direct comparison, human "g" accounts for 40 to 60 percent of the variation in an individual's performance on the various subtasks of an IQ test. It may be that an increase in the magnitude of "g" was integral to the evolution of the human brain.
"General intelligence is an important component of human intelligence, but it is also possible that it relies upon ancient neural substrates," says Banerjee. "If different primate taxa differ in the magnitude of 'g,' with humans standing out from the rest of the pack, this might help explain how we, uniquely, can combine thoughts from different domains of knowledge to create new representations of the world. This cognitive domain general ability, captured by 'g,' is something that you might see to varying degrees in other primate taxa."
This study was conducted among 22 cotton-top tamarins, who
were administered 11 unique tasks designed to assess different cognitive
functions including working memory, executive control, information
processing speed, and inhibitory control. For some tasks, the monkeys' goal
was to obtain a piece of food, but this was not the case for all of the
tasks. Monkeys with higher "g" scores tended to outperform monkeys with
lower scores across the various subtasks in the cognitive task battery.
"We called our cognitive task battery the 'monkey IQ test' very crudely," says Banerjee. "It's a fun way to think about it, but to be more accurate, I would say that we are looking at global cognitive ability across an array of tasks that span multiple cognitive domains."