But Premack's findings
concerning Sarah's abilities to conserve quantity, to reason analogically and to attribute object
qualities to
abstract symbols, does establish that primates are capable of more abstraction than Whitehead believed to be the case.
The original band of innovators themselves gradually changed their styles after 1948, working in larger format and substituting, in their varied ways, more
abstract qualities for the earlier
concern with fantasy and chimerical subject matter.