When we enter a situation, we don’t just enter it cold. We don’t travel light. We bring along all of the baggage that we’ve accumulated in our life, every experience and thought and prior perception that has been stacked away, both knowingly and not, in that very mind attic that Holmes urges us to clean out with due vigilance. But clean or not, the attic is never empty.
While several theories strive to untangle what exactly it is that travels with us to any new setting, my personal favorite approach is CAPS: the Cognitive Affective Personality System model developed by psychologistsand Yuichi Shoda to explain why it is that Holmes sees crime where Watson sees freshness and beauty (granted, that may not have been their precise motivation in developing the theory).
The CAPS premise is relatively simple: different people respond differently in the same situation, and the same person responds differently in different situations. But in the variance, there is consistency, a so-called behavioral signature which identifies if-then contingencies for a specific person. So, to use Holmes and Watson as our guiding examples, we can start with the following statements. If Holmes sees houses in the country, then he reacts to them as to possible strongholds of crimes. If Watson sees the houses, then he reacts to them as to beautiful places of leisure.