Barbara Landau's  picture
Barbara Landau
Dick and Lydia Todd Professor of Cognitive Science
The Johns Hopkins University

The Computer Between Our Ears

“This does not compute.” To anyone of a certain age, this phrase may bring up reminders of the Robinson family, in a TV series called “Lost in Space” – where a robot aboard the spaceship that crashed on an unknown planet frequently uttered his frustration that he couldn’t process what was going on. Even for those not around to see science fiction in black-and-white on the small screen, the phrase has evolved into a present-day text-talk as DNC.

What does compute (DC) is the most sophisticated processor known to humankind, the brain. And while neither science nor philosophy can yet unravel all the answers to how it became the sophisticated computer that gave rise to modern humanity, we do know that it is a powerful tool for understanding language, for moving around in space, for reasoning, and decision-making.

What science has been able to tell us is that the anatomical scaffolding of the brain is in place in healthy human development at birth, but that it continues to be built upon throughout the lifespan.

Two hemispheres, or halves of the brain, appear quite similar to each other in overall structure but they differ somehwat in function. The specialization in function is remarkable.

The Lobes of the BrainThese halves are further divided into different lobes (Figure 1). The occipital lobe, in the back of the brain at the base of the skull is responsible for many of our visual abilities. The occipital lobe is home to the primary visual cortex (V1), as well as other higher-order visual areas, which allow us to perceive shape, color, some aspects of objects, and some kinds of motion.

Anterior to the occipital lobe is the temporal lobe, the home of audition (hearing) and many language functions. Within this lobe are also areas that are responsible for our processing of objects and faces. So the very first impressions in a baby’s world – recognizing a mother or father’s face – form here. In the medial temporal lobe is the hippocampus - from the Latin for “seahorse,” so named for its shape – which is critical for two vital functions: the formation of memories, and navigation, – what helps us get around space.

The parietal lobe is situated in front of the occipital lobe, and behind the frontal lobe. One of the main landmarks in the parietal lobe is the intraparietal sulcus (IPS), which is essential for a variety of spatial functions and also for numerical computations.

Finally, the frontal lobe is anterior to the parietal lobe, and not surprisingly at the front of the brain. The frontal lobe is home to several different areas. One is the primary motor cortex which works with the parietal lobe to control much of our visual-motor activities, including simple things such as our ability to accurately reach and grasp objects. The areas towards the front of this lobe are best known for their importance in so-called “executive functions,” which are important for human decision-making and problem solving.