Duality Personified --

While interceptions in general represent less accessible areas of our persona, first house interceptions become particularly interesting -- considering that this house deals with the identity and how we present ourselves to others. 

When there is an interception in the first house, it seems as though there are two separate levels of projection of the individual that others perceive. While the sign positioned on the Asc is the most readily accessible and usually the first seen, especially early in life -- the other (representing the intercepted sign) periodically will display itself, with potentially quite confusing interactions with individuals in close contact with the client. Even the client him/herself may be confused by the behavior until the diverse tendencies become better understood.

The most dramatic examples that I have observed are clients with Pisces on the Asc and Aries intercepted in the 1st. More often than not (in my experience), these clients have two distinct projections to others. The most often encountered, the Piscean energies display as compassionate, caring, and willing to help others --especially those deemed less fortunate. But lurking beneath this benevolent exterior is an altogether different persona. There is a self-promoting, aggressive, assertive, competitive side that, as the person becomes more familiar with the energies -- can provide a Dr. Jekyll and Mr. Hyde range of personal projection.

Once the client learns that these two diverse energies exist they can begin to learn to use the one that is most appropriate for a given set of circumstances. The result can be quite versatile and powerful indeed. It is important to keep in mind that an interception in the first house will always be opposed by another in the 7th -- the house of 1 on 1 relationships. With our example of Aries intercepted in the first, we would necessarily also have Libra intercepted in the 7th, with Virgo on the Descendant. We would anticipate the corollary effects to be an intense (over-?)analysis of relationships, with a tremendous underlying need for harmony, fairness, and balance. This positioning, in particular, would likely be extremely confusing for a partner.

A very demonstrative example of this Aries interception in the first is Allen Ginzberg.  Excerpts of the biographical notes in AstroDatabank Database follows (emphasis added to highlight salient points):

American writer and poet, the bearded bard of scatological colloquialisms who became the symbol of the anger under flower-power. Asked once to define his political and social views, Ginsberg said simply: "Absolute defiance." Ginsberg credited his mother ... with instilling his "mad idealism."

While diversity would be anticipated with any combination of the rising sign and the intercepted sign, sometimes the results would be expected to be more subtle (e.g. Aquarius on the Asc and Pisces intercepted in the 1st) than with the previous example.

Similar effects could likely be observed with all houses containing an interception, but my suspicions are that the angular interceptions would exhibit themselves most prominently.