Giambattista said:
It doesn't take a genius to predict that pressing a hot iron against someone's skin will, 99% of the time, make them pull away and yelp in pain.
It DOES take more intellect (and perhaps a little luck) to predict whether a person will say "Yum" or "Yuck!" when presented with a plate of steamed broccoli. Or to predict whether a person prefers red, or purple as a color.
What you appear to be disregarding are the constants and the predictables in these hypothetical situations, while focusing on the unknowns.
What are some of the constants?
1. We know that there will be
some reaction when they are presented with a plate of steamed broccoli.
2. We know this reaction will vary from individual to individual.
3. We know that the reaction will be conditioned (in both the Pavlovian and non Pavlovian sense) by genetic factors, and by prior experience of foodstuffs in general and broccoli in particular. i.e. nature and nurture will have a role to play.
4. We know this reaction may vary from individual to individual, over time, and from time to time.
5. We know that the reactions 'Yum!' and 'Yuck' are reactions that are employed in other situations.
6. We know that people may
have preferences for colours.
The list could be easily extended. It is equally easy to make psychology appear unpredicatable, and based upon opinion, guesswork and luck. The same can be done with any science if we focus on the areas beyond current understanding. This would be more unfair to the hard sciences, but it still seems misguided when applied to psychology.
You say -
preferences may change without warning. Not so. Psychologists can define a range of causes in the internal and external environment of the individual that may cause a change of preference.