Pigeons can discriminate abstract concepts of space and time, and appear to use a different region of the brain than humans and primates do, according to new research published in the journal Current Biology . The finding adds to the growing recognition in the scientific community that lower-order animal species are capable of making high-level abstract decisions.
Humans can perceive space and time, even without the aid of inventions such as a clock or a rule.
The region of the brain that helps humans make those more tangible abstract concepts is the parietal cortex, part of the cerebral cortex and the outermost layer of the brain.
It is known that the cerebral cortex is a place of higher thought processes, including speech and decision making, and the four lobes that comprise it, including the parietal cortex, process different types of sensory information.
But the brain of the pigeon does not have a parietal cortex, or at least one developed enough to be different.
Then, birds must use another area of the brain to discriminate between space and time, or there may be a common evolutionary mechanism in the central nervous system shared by primates and primitive birds.
"The cognitive dexterity of birds is now considered increasingly closer to that of humans and non-human primates," said lead author Edward Wasserman of the University of Iowa.
"These systems nervous aviars are capable of much greater achievements than the pejorative term "bird brain" would suggest.
Professor Wasserman and company – the authors put the pigeons through a series of tasks called the "common magnitude" test  Briefly, birds are displayed on a computer screen with a horizontal line of 6 cm or 24 cm long for 2 seconds or 8 seconds.  If they reported correctly – by pecking one of the four symbols visuals – the length or length of the line, they received food.
The test became more nuanced: the researchers introduced additional line lengths, thus adding greater variability in judging whether a Line was short or long; They also presented the line to the pigeons for a shorter or longer duration.
"The task now forces the pigeons to process time and space simultaneously because they can not know in which dimension they are going to be tested," said Professor Wasserman. .
The team discovered that the length of the line affected the pigeon discrimination of the line duration, and the length of the line affected the line length discrimination of the pigeons.
This interaction of human and monkey space and time and revealed the common neuronal coding of these two physical dimensions.
Scientists previously believed that the parietal cortex was the site of this interaction. However, because pigeons lack an apparent parietal cortex, the new findings suggest that this is not always the case.
"The results show that pigeons process space and time in a similar way to humans and other primates," said co-author Benjamin De Corte, a student at the University of Iowa.
"The cortex is not unique to judge space and time, pigeons have other brain systems that allow them to perceive these dimensions. "
Benjamin J. De Corte et al. . 2017. Coding of non-cortical magnitude of space and time by pigeons. Current Biology 27 (23): R1264-R1265; doi: 10.1016 / j.cub.2017.10.029