Yesterday, I appeared as a guest on GluckRadio (listen here) to discuss my book The Consuming Instinct: What Juicy Burgers, Ferraris, Pornography, and Gift Giving Reveal About Human Nature. At one point, the two hosts and I were chatting about universal mate preferences including the fact that women place greater importance on a man’s status (than the other way around). In her retort, the female host committed a classic cognitive fallacy, namely she generated individual examples that were meant to “falsify” the general rule (which is veridical at the population level). Apparently Elizabeth Taylor and Barbara Streisand had dated a “low status” construction worker and hairdresser respectively so the Darwinian edifice is supposedly shattered! See my earlier post on this exact lack of understanding of statistical/scientific reasoning: Katie Holmes is Taller Than Tom Cruise: This Proves that Men Are Not Taller Than Women…No It Doesn’t!
In many instances mate choice is a compensatory process. In other words, both men and women choose prospective mates by combining their scores on several key attributes. This is the reason that despite the fact that I am of short stature (all other things equal, women prefer taller men), I married a highly desirable woman. My height (or lack thereof) was compensated by other qualities (too modest to list them all!). With that in mind, behavioral decision theories distinguish between two types of decision-making strategies, namely compensatory and non-compensatory rules. I’ll discuss three such rules, the Weighted Additive Rule (compensatory), the Lexicographic Rule (non-compensatory), and the Conjunctive Rule (non-compensatory), each of which will be explained below.
Let’s use a very simple example. Suppose that you are choosing between two mates each of whom is to be evaluated on three attributes using a 1-10 scale (higher means better): status, personality, and looks. Furthermore assume that for you, status is twice as important as looks and personality combined, the last two of which are equally important to you. In other words, status has a weight of 0.50 while personality and looks each have a weight of 0.25 (note that the weights add up to 1). Let’s presume that the two individuals A and B score as follows on each of the three attributes:
Individual A scores a 2, 8, and 9 on status, personality, and looks respectively.
Individual B scores a 4, 1, and 1 on status, personality, and looks respectively.
Let’s see what happens when we apply each of the three rules to the aforementioned choice.
Weighted Additive Rule
For each alternative do the following: For each attribute, multiply its score by its importance weight and add these up to arrive at a total score. Repeat for both alternatives and then choose the alternative that scores the highest overall.
Individual A’s total score is: (2 x 0.50) + (8 x 0.25) + (9 x 0.25) = 5.25
Individual B’s total score is: (4 x 0.5) + (1 x 0.25) + (1 x 0.25) = 2.50
Hence, since Individual A’s overall score is greater than Individual B’s, he/she is the winning alternative. Note that despite the fact that Individual A scored poorly on status, he/she was able to compensate for it by scoring highly on the other two attributes.
Now let’s look at the Lexicographic Rule (non-compensatory).
Choose the alternative that scores the highest on your most important attribute (status in the above example). Since Individual B scores higher than Individual A on status (4 versus 2), he/she is chosen. It does not matter that Individual A is the better overall catch. He/she cannot compensate for the fact that Individual B wins out on status.
Let’s examine another non-compensatory rule known as the Conjunctive Rule.
Inspect each of the competing alternatives and only keep the ones that pass your minimal attribute cutoffs. For example, you might be unwilling to date an individual who does not score at least a 5 on each of the three attributes. In such an instance, both individuals A and B would not be chosen, as they each have at least one attribute whose score is below 5.
So to summarize:
When the Weighted Additive Rule was used, Individual A was chosen.
When the Lexicographic Rule was used, Individual B was chosen.
When the Conjunctive Rule was used, both individuals were rejected!
Interested readers might wish to visit my earlier post titled Sex Differences When Choosing Vs. Rejecting Mates.
Returning to the point raised by the female host, you can now see how Elizabeth Taylor might have chosen to date the construction worker. Ms. Taylor's mate choice does not in any way negate the fact that when choosing mates women value status much more than men do. Incidentally, the preference for high-status men increases for contemporary women who are powerful and wealthy.
Note that which rule a given individual uses will depend on various contextual factors including whether he/she is looking for a short-term fling or a long-term partner. For example, one who is looking for a casual liaison might use the Lexicographic Rule using looks as the sole relevant attribute (“I will choose the best-looking prospect to have sex with”) while the same individual might use the Weighted Additive Rule when choosing a husband/wife. This parsing of cognitive rules into a distinction between short-term versus long-term mating is at the heart of Sexual Strategies Theory as enunciated by David M. Buss and David P. Schmitt.
After I had ended my conversation with the two hosts, they chatted with one another about my work (listen to the last few minutes of the taped interview). As is common among those who do not have a good grasp of the biological bases of sex differences, the hosts (especially the female interviewer) thought that many of the evolutionary principles that I discussed in my book were “sexist” and “reductionist.” Nice!
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