Dana's religious convictions were both orthodox and intense. However, he rigorously kept his convictions from getting ahead of accurate observation and inference. He expected that, if God wanted him to know the truth of things, God would use nature itself to tell him. Scripture was, after all, never meant to be a technical manual.
Dana rigorously let the great manuscript of nature point his way. After Darwin published Origin of Species, Dana waited a few years. Then he wrote,.
Dana continued to argue for minimal divine intervention, but he did accept evolution by natural selection. Meanwhile, when he was not adding to his huge output of scientific writing, he wrote both hymns and love songs for the guitar. My first grounding in science came from Dana, 43 years after he died. My father took a University class in geology. He'd come home and tell me the exciting things he was learning. Then, in our workshop, we'd use Bunsen burners and blowpipes to redo Dana's mineralogy experiments.
That was magical stuff for an eight-year-old. I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work. Rice, James Dwight Dana, Geologist Click here for audio of Episode Dana describes the subisdence of reefs in his Manual of Geology.
For an example of one of Dana's more dramatic illustrations, click on the thumbnail below for his drawing of two Phymactis organisms and two smaller sketches of polyps:. Lienhard Click here for audio of Episode Then he wrote, The evolution of the system of life went forward through derivation of species from species, according to natural methods not yet clearly understood, and with few occasions for supernatural intervention. Theme music W.
Stanton, Dana, James Dwight. Dictionary of Scientific Biography C. Gilespie, ed. New York: Charles Scribner's Sons, Dana, Corals and Coral Islands. Dana, Manual of Geology. Scientists learned through postmortem examinations and, more recently, neuroimaging studies that a specialized part of the right hemisphere is involved in facial processing. We can understand this better by looking at how visual information in general is processed by the brain.
Understanding the neuronal pathways involved in vision—from the eye to the brain to the achievement of object recognition—once seemed terribly complicated, engaging a multitude of perceptual and cognitive elements. Now, we have a good overview of this visual processing system.
It begins when sensory information from the eye enters the primary visual cortex in the posterior part of the brain, activating a series of neurons upward in the dorsal stream and downward in the ventral stream.
Each pathway has a distinct function in processing. In the ventral stream, forms, colors, and faces are found. On the hilly topography of the brain is a region called the occipitotemporal cortex, which processes visual information.
By means of measuring regional cerebral blood with positron emission tomography PET and functional magnetic resonance imaging fMRI scans, scientists have discovered that this part of the brain is active when people look at faces. This divergence of opinion is part of a larger debate in neuroscience. Others, however, argue that the brain consists of more general mechanisms that are broad enough to handle a variety of different processing operations for example, faces but also other visual signals.
Faces, according to this latter view, would acquire their special status through repeated exposure. Look at the face to the right.
Now, turn the page and see how much easier it is to recognize him when the picture is upright. This phenomenon is called the facial inversion effect. Because inverted faces convey the same information as upright faces— all features and relationships are identical, only the orientation differs—one might expect similar visual processing patterns and cerebral involvement.
But experiments show that different cortical locations are involved in processing inverted faces, providing further evidence that the FFA is a module dedicated to the processing of upright faces. Frank Tong, Ph. Curiously, people with prosopagnosia tend to do relatively better identifying inverted faces than upright ones, which suggests that upright normally viewed faces are processed by a different cluster of neurons than are inverted faces.
Processing inverted faces seems similar to processing other complex visual stimuli, for example, a painting of a pastoral scene by Monet— that is, it appears to involve a partial decomposition of a whole face into components. Here, we illustrate the effect below with Tom Cruise. The depiction of human faces has been a theme of artists from ancient Egyptian wall paintings, to early Hebrew and Christian representations, to Renaissance portraits, to modern abstract paintings.
Some contemporary artists present us with distorted faces such as the disturbing portrait by Francis Bacon on the next page. In frustrating our normal propensity to understand and process, Bacon forces us to look deeper into the picture.
Consider a famous artist such as Raphael, arguably the most important portrait painter of the Renaissance. What cerebral activity might be going on as he composed Madonna of the Meadow ? Now, consider the areas of the brain activated by various components of the painting. In the case of Madonna of the Meadow , one might focus on the face of Mary, then on the colors, then on a geometric form, and then on cues to perspective, such as distance.
Initially, I tested the feasibility of the study by modifying an MRI machine so I could copy a portrait of a face while having my brain scanned. The results indicated that successful data could be collected this way, and a detailed study was launched in which a leading portrait painter drew a series of faces while undergoing fMRI analysis. Humphrey Ocean, named by the National Portrait Gallery in London as one of the foremost portrait artists of the 20th century, consented to having his brain scanned as he drew a series of faces.
Measures of his brain activity6 were contrasted with a control subject who had no particular training in art. The results are shown on the next page. Perhaps Ocean is so well practiced at facial perception that he is less likely than a novice to ponder the features and gestalt of a face. Our faces, which we take so much for granted as we shave or apply makeup each morning, are a powerful and privileged component of our nature, with an important role in evolution, social life, and art.
Are those who perform before the public—hundreds, thousands, even millions of spectators at a time—at heightened risk of mental illness? The Brain Prize went to four individuals whose independent research led to useful treatments for a disorder affecting a billion people.
A sampling of work by Dana Simmons, Ph. A psychiatrist falls seriously ill, and considers anew the dogma not to share details of one's life with one's patients. Our authors, who study successful aging and mental illnesses at the University of California, San Diego, address the much-debated, complicated question that many of us have long wondered about: Does the brain improve with age?
Sign up for monthly email updates on neuroscience discoveries, Cerebrum magazine, and upcoming events. Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website.
These cookies do not store any personal information. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website. Back to Parent Page. Share This Page. Faces and Survival Almost all creatures, from dogs to canaries, gorillas to penguins, salamanders to crocodiles, kangaroos to spiders, and certainly members of our human family, manifest the same formula for facial composition: a forehead, two eyes, a nose, a mouth, and a chin that are in the same relative positions.
According to Paul Ekman, facial expressions of emotion—anger, happiness, disgust, surprise, sadness, fear—are universal across cultures. Anne Solso, courtesy of Robert L.
Solso The Universality of Facial Expression Human facial expressions are also designed to arouse reactions from others. Learning from Face Blindness If nature has furnished us with special adaptive skills for facial expression, how are these skills manifested in our brains? A normal view of a face top , and the same face as a prosopagnosiac might see it. Solso Visual Processing in the Brain Understanding the neuronal pathways involved in vision—from the eye to the brain to the achievement of object recognition—once seemed terribly complicated, engaging a multitude of perceptual and cognitive elements.
Some areas of the brain show increases in blood flow, indicating stepped-up activity, when we process visual information. The red areas, especially the fusiform gyrus, are most active in recognizing faces. Solso On the hilly topography of the brain is a region called the occipitotemporal cortex, which processes visual information. Inverted Faces Look at the face to the right.
Do you recognize this well-known person?
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