Editing Human intelligence (section)

=== Process, personality, intelligence and knowledge theory (PPIK) ===
{{Expand section|1=more extensive and clear explanations|date=March 2018|small=no}}
[[File:Development of intelligence with age.jpg|thumb|Predicted growth curves for ''Intelligence as process'', crystallized intelligence, occupational knowledge, and avocational knowledge based on Ackerman's PPIK Theory{{citation needed|date=March 2018}}]]
Developed by Ackerman, the PPIK (process, personality, intelligence, and knowledge) theory further develops the approach on intelligence as proposed by Cattell, the [[#Investment theory|Investment theory]], and [[Donald O. Hebb|Hebb]], suggesting a distinction between ''intelligence as knowledge'' and ''intelligence as process'' (two concepts that are comparable and related to [[Crystallized intelligence|''g<sub>c</sub>'']] and [[Fluid intelligence|''g<sub>f</sub>'']] respectively, but broader and closer to Hebb's notions of "Intelligence A" and "Intelligence B") and integrating these factors with elements such as personality, motivation, and interests.<ref name="Ackerman">{{cite journal | last1 = Ackerman | first1 = P. L. | year = 1996 | title = A theory of adult intellectual development: Process, personality, interests, and knowledge | journal = Intelligence | volume = 22 | issue = 2| pages = 227–257 | doi=10.1016/S0160-2896(96)90016-1}}</ref><ref name="Ackerman2">{{cite conference|last=Ackerman|first=P.L.|year=1995|title=Personality, intelligence, motivation, and interests: Implications for overlapping traits|conference=Address presented at the annual meeting of the American Psychological Association|location=New York}}</ref>

Ackerman describes the difficulty of distinguishing process from knowledge, as content cannot be eliminated from any ability test.<ref name="Ackerman"/><ref name="Ackerman2"/><ref>{{cite journal|last1=Detterman|first1=D.K.|last2=Andrist|first2=C.G.|year=1990|title=Effect of instructions on elementary cognitive tasks sensitive to individual differences|journal=American Journal of Psychology|volume=103|issue=3 |pages=367–390|doi=10.2307/1423216 |jstor=1423216 |pmid=2221194 }}</ref>

Personality traits are not significantly correlated with the ''intelligence as process'' aspect except in the context of psychopathology. One exception to this generalization has been the finding of [[sex differences]] in cognitive abilities, specifically abilities in mathematical and spatial form.<ref name="Ackerman"/><ref>{{cite journal | last1 = Signorella | first1 = M.L. | last2 = Jamison | first2 = W. | year = 1986 | title = Masculinity, femininity, androgyny and cognitive performance: A meta-analysis | journal = Psychological Bulletin | volume = 100 | issue = 2| pages = 207–238 | doi=10.1037/0033-2909.100.2.207}}</ref>

On the other hand, the ''intelligence as knowledge'' factor has been associated with personality traits of Openness and Typical Intellectual Engagement,<ref name="Ackerman"/><ref>{{multiref2
|1={{cite journal|last1=Rolfhus|first1=E.L.|last2=Ackerman|first2=P.L.|year=1996|title=Self-report knowledge: At the crossroads of ability, interest, and personality|journal=Journal of Educational Psychology|volume=88|pages=174–188|doi=10.1037/0022-0663.88.1.174 }}
|2={{cite journal|last=Rocklin|first=T.|year=1994|title=The relationship between typical intellectual engagement and openness: A comment on Goff and Ackerman|journal=Journal of Educational Psychology|volume=86|pages=145–149|doi=10.1037/0022-0663.86.1.145 }} }}</ref> which also strongly correlate with verbal abilities (associated with [[crystallized intelligence]]).<ref name="Ackerman"/>