Ralph Holloway, an anthropologist who pioneered the idea that changes in brain structure, and not just size, were critical in the evolution of humans, died on March 12 at his home in Manhattan. He was 90.
His death was announced by Columbia University’s anthropology department, where he taught for nearly 50 years.
Mr. Holloway’s contrarian idea was that it wasn’t necessarily the big brains of humans that distinguished them from apes or primitive ancestors. Rather, it was the way human brains were organized.
Brains from several million years ago don’t exist. But Dr. Holloway’s singular focus on casts of the interiors of skull fossils, which he usually made out of latex, allowed him to override this hurdle.
He “compulsively collected” information from these casts, he wrote in a 2008 paper. Crucially, they offered a representation of the brain’s exterior edges, which allowed scientists to get a sense of the brain’s structure.
Using a so-called endocast, Dr. Holloway was able to establish conclusively, for instance, that a famous and controversial two-million-year-old hominid fossil skull from a South Africa limestone quarry, known as the Taung child, belonged to one of mankind’s distant ancestors.
The Taung child’s brain was small, leading many to doubt the conclusion of Raymond Dart, the anatomist who discovered it in the 1920s, that it was a human ancestor.
In 1969, Dr. Holloway took his family to South Africa to meet the elderly Dr. Dart, to examine the natural limestone endocast that the Taung child’s positioning in the quarry had created and to make an endocast of his own.
“I became convinced that the Taung endocast needed independent study,” he wrote in 2008, in order to “find an objective method(s) for deciding whether the cortex was reorganized as Dart had previously claimed,” so many years before.
Dr. Holloway focused on a crescent-shaped furrow, called the lunate sulcus, at the back of the endocast. In his view, it was positioned like a human’s, which suggested to him that Dr. Dart had been right all along.
Others in the field had insisted that the Taung lunate sulcus was in a “typical ape anterior position,” he wrote.
By now, the conclusions made by Dr. Holloway and Dr. Dart about the lunate sulcus have largely been accepted: The Taung child is a human ancestor.
“If you can define where it is and prove it, then you can really demonstrate that it is an aspect of reorganization,” Dr. Holloway told an interviewer for Archaeology magazine in 2007.
That concept — the brain’s structure rather than its volume — was the decisive factor in proving human ancestry.
“I was taking the position, as had Dart before me, that reorganization took place prior to the increase in brain volume,” Dr. Holloway wrote in 2008.
“I believed then and remain convinced today that the earliest hominids, i.e., Australopithecus africanus, A. afarensis, and A. garhi, had brains that were definitely different from any ape’s, despite their small size,” he added.
Early in his career, he had decided, unlike many of his peers, that the mere study of apes wasn’t enough. “I could not fathom using baboons as a theoretical model for understanding human evolution because I regarded each species as a terminal end product of their own line of evolutionary development,” he wrote.
It was humans, and the fossils of their ancestors, that needed to be the focus. “He was very important in paleoanthropology, in bringing the study of brain evolution from being a marginal enterprise to the center,” said Chet C. Sherwood, a biological anthropologist at the George Washington University, in an interview.
“And he did it by innovating methods for reconstructing cranial morphology,” said Dr. Sherwood, who studied under Dr. Holloway at Columbia in the 1990s.
The confrontation between Dr. Holloway and his “reorganization” partisans, on the one hand, and neuroanthopologists who insisted that Taung and similar specimens were more likely apes, on the other, could become “extremely emotionally charged,” Dr. Holloway wrote. Of one such encounter, he wrote that “fortunately, at 430 ml, the endocasts could not do much damage even if thrown, despite being made of plaster.”
Dr. Holloway was in some respects a traditional anthropologist, committed to what the discipline once called the “four fields” of anthropology: archaeology and cultural, biological and linguistic anthropology. But that multidisciplinary approach has long fallen out of favor, with biologists increasingly pushed aside.
“I was quickly isolated and marginalized at Columbia, and remain so,” he wrote in 2008.
He was further isolated when he defended the educational psychologist Arthur R. Jensen, remembered for a deeply contested 1969 Harvard Educational Review article positing a genetic explanation for a divergence in I.Q. scores between Black and white people. One fellow anthropologist called him a “racist,” Dr. Holloway wrote, after “I had the temerity to defend Arthur Jensen” from an “assertion that Jensen was a bigot.” Some who knew him said the charge was deeply unfair.
Ralph Leslie Holloway Jr. was born on Feb. 6, 1935, in Philadelphia, to Ralph Holloway, who was in the insurance business, and Marguerite (Grugan) Holloway, a secretary. He attended high school in Philadelphia and enrolled in Drexel Institute of Technology’s metallurgical engineering program.
He later moved with his family to Albuquerque, where he studied anthropology and geology at the University of New Mexico, graduating in 1959 with a degree in geology.
After working for a time in the oil fields of southwest Texas and for Lockheed Aircraft in Burbank, Calif., he entered the graduate program in anthropology at the University of California, Berkeley, where he received his Ph.D. in 1964. That year, he was recruited by Columbia as an assistant professor, and he remained there until his retirement in 2003.
He was the author of or contributed to several books, including “The Role of Human Social Behavior in the Evolution of the Brain” (1975).
Dr. Holloway is survived by his daughter, Marguerite Holloway, and two grandchildren. Two sons, Eric and Benjamin, and his first and second wives, Louise Holloway and Daisy Dwyer, are deceased.
For his entire career, Dr. Holloway remained focused on a single organ, the brain, and on the three-dimensional modeling he perfected to study its development.
“Because the human brain is the most important constructor of experience and reality, it would be important to know how it came to its present state,” he explained at the end of his career.
“Endocasts, i.e., the casts made of the internal table of bone of the cranium, are rather impoverished objects,” he continued, “to achieve such an understanding, but these are all we have of the direct evolutionary history of our brains and should not be ignored.”
