How does intelligence relate to this theory?
Intelligence doesn’t relate very well at all. It’s very hard even to define intelligence in a meaningful way. Howard Gardner’s work probably best explains the concept as it describes and legitimizes at least nine ‘intelligences’ that include physical, emotional, and intellectual pursuits. The old notion of I.Q. isn’t inclusive enough, and even in Graves’ day he found poor correlations between his work and the intelligence measures then available, except in the case of seriously mentally challenged persons who had low I.Q. scores and rarely exhibited behavior beyond the B-O range. Instead, he discovered people of both high and relatively low intelligence (as he could measure it) centralized around the A’-N’ (Yellow) level, the D-Q, and the rest. Effectiveness in coping is a different dimension.
So, “up” the Spiral is not a move to greater intelligence any more than it is a move up a spiritual ladder to higher consciousness, though it does describe a hierarchy of ways of thinking about consciousness and approaching explorations of self/others. The awakening of new levels adds to the behavioral repertoire and introduces new factors for consideration when making life’s choices. Many scholars propose movement along continua of cognitive complexity and an increasing ability to sort through more factors simultaneously—more elaborated thinking processes—but that’s not the same as intelligence in the conventional sense.
What does seem to move along the Spiral is the valuing of different intelligences. If one looks at Gardner’s list, we can see that people centralized in different Gravesian worlds might well need to emphasize various kinds of intelligence, and how the ‘well-adjusted’ person in those worlds would need to be ‘smart’ in ways which address the existential problems at hand. While this might be viewed as a cultural artifact, the valuing of intelligence(s) is one of the things which differentiates levels.