Read about The Theory of Interest first, if you've come here because of women. Otherwise, check the table of contents. Despite model scenarios, you can lose some illusions here.

Pokud jste tu kvůli ženám, přečtěte si, o čem Teorie zájmu vlastně je. Jinak zkuste rovnou obsah. Ač uvedené jsou modelové situace, nedivte se, když tu přijdete o iluze.

Equation of Interest Level Motion  

Posted by SomeoneCZ in ,

Cary Grant and Ingrid BergmanIf she has to go out on a date with you, she must be interested enough to do so. If she has to kiss you, there must be enough of her interest for the kiss to happen. If she has to stay with you in a long-term relationship, she must be interested in doing so and she must be interested in you as well.

If you do not understand, why she does not return your phone calls, why she committed adultery, why she flinched from your kiss, why she has a headache, why she ignores you, or why she rejected you, you do not understand the role of interest level and you don’t know, how it relates to her attitude. And therefore, keep reading;-)

Popular, yet totally aberrant myth says that no two women are the same. Sure, none is 100% identical when it comes to her ideas, opinions, experiences, etc. Yet, they have something in common. And how do we know what is that? We use a testing technique called Black Box [32, 33]. We give her some inputs and evaluate the output. Once we have enough of information, we can postulate a theory on how it looks inside. Technically speaking, woman is a sequential automaton with a non-trivial logic. Getting all the required information takes several years, so I take the luxury of giving you just the results - with taken of The System [2] too. Each of you can verify their correctness in a practice.

As a simplifying condition, I assume clinically sane woman as [2] does.

Personal Interest Level vs. Relationship Interest Level

Consider the predicate logic and try to answer this question: does she love me? Or better, does she want to stay with me? The answer will be either yes (1), or no (0). And now, try to consider the fuzzy logic. The answer will be in the range of 0 – 1; i.e. 0% – 100%. And we have the same rating as used by The System [2]. However, we will expand it.

First and key mistake is to consider personal and relationship interest levels as the same. This is not true. Although they are connected, they are two different quantities. Another mistake is to automatically consider a relationship as a long-term one. One night stand is a kind of a relationship as well. I’ll talk about the relationship interest level later, now I’ll talk about the personal interest level.

Fig. 1: Interest Levels

Point of no return, H, F, I and L represent particular thresholds, which determine states she can take against you. As I’ll stress later, interest is a non-linear function. Thus, efforts to raise the interest level by e.g. 5% are not the same for 51% and 65% as starting positions. It is important to realize that we can order the states and define rules for transitions between neighbor states. Threshold numbers were given by an assessment, based on statistics. To quote sergeant Colon, letters are for people who do not know how to count with real numbers.

  • <-100%, -75%) – Hate: At this level, you cannot stand the other person in the same room, so there’s no possibility of having a relationship (worth lasting).

  • <-75%, -25%) – Impassivity: Well, you can withstand the other person in the same room, but you completely don’t care about him/her. There’s nothing to build the relationship from.

  • <-25%, 0%) – Friendship: If you have started at this level, there always will be somebody with a possibly higher priority than you have. If you have started on a higher level than this one, it is still possible that you live in an illusion of a relationship, but the relationship is already gone.

  • 0 – Point of No Return: Sooner or later, you’ll have to make a decision that will clarify the interest in you. Is it in positive or negative numbers? It never will be the exact zero.

  • (0%, 5%> – Hard to Read: Here, you have a real chance that she could fall in love with you someday. However, her interest level is so low that it is hard say it is in positive numbers. Therefore, it pays off to continue as it would be positive, until you encounter a clear sign of low interest level. At this level, it could take just one small mistake to loose her, i.e. to send her interest level under the point of no return. So, fames, as women do not know what they want, are born. If your relationship with Miss Right goes to hell, this is your last chance to save it. Yet, most men successfully ignore the opportunity without noticing it and fames are born again.

  • (5%, 75%> – High Interest: You have not fallen in love yet, but as interest levels of both of you are high, you can start considering it as a relationship. However, she has some interest levels in other guys as well and therefore this level does not guarantee the relationship automatically even with Miss Right. If she is in love with somebody else, you are going to end as a friend. Yet possibly a friend that could became something more in time. So, once you’ll hear that you cannot be just friends with a woman, or that a friend became girlfriend, you’ll know that it is about this interest level.

  • (75%, 100%> – Love: If you want to keep your partner, and his/her interest level in you got here, you’re doing fine. Even if there will be interest level in somebody else that would be higher than the one in you, it would fall down as people in love tend to put their beloved ones on pedestals. Just remember, we talk about real love – action speaks louder than thousands words. Terms such as "marriage love" are being used for interest levels, which are often below the point of no return, as they stay together because of other reasons than the positive interest level – see later.

People tend to mistakenly suppose that it is possible to love and hate the very same person. This is not true. You can love her look and hate her attitude. Or, you can love her and be mad at her for something. This is possible. As I stressed, I consider clinically sane woman;-)

As we use the Black Box technique, we don’t know how it works inside. Nevertheless, we can postulate following characteristics for the interest level:

  • She has to find you physically attractive to have high interest level. No physical attraction, no interest in positive numbers.

  • The interest level can go up and down. Yet, once it gets below the point of no return, it will never get back into positive numbers. Therefore you can find your ex, which would deny new relationship with you.

  • The interest level is being affect by your behavior for all the time you know each other. Therefore, the point of no return means no return from negative numbers to positive ones.

  • It is possible to permanently lower maximum interest level you can achieve with her. A typical example is a revealed adultery.

  • Interest level does not change with a constant velocity. Mainly, at 21 old girls, +/- 2 years, you can notice that it takes a little for a significant change. This gives four years, when you want enjoy the wild ride, second puberty, call it whatever you like – in the outcome, it drastically cuts your chances for keeping her interest level high. It is not unusual that a girl in this age seeks a relationship e.g. for one year only. Until she’s at least 23 [2], take it as a fun, not as something that would last centuries to come. If you manage to keep it cool, you have better chances to keep her.

  • The interest level changes because of many actions of yours. She evaluates them sequentially. Therefore, it is possible to make several mistakes consequently and have her interest level still in positive numbers. That’s the reason, why some advices are considered as good, even as they lower her interest level in fact. It always rules that the more you lower the interest level, the worse for you.

Let T be the total time for which you know each other. Then we can consider the interest level in you, Personal Interest Level, as a function:
PIL is an instantaneous value of the pil function – the interest level in you in time t, which we measure since the time she knows you. I stress that we talk about a non-linear function.

As previously stated, it is a sequential automaton. Current value of pil function depends on history – the previous values. As an example from practice, while a girlfriend in love smiles even to corny jokes, ex does not do so. The PIL makes the difference.

Next important factor is feedback. You affect interest of other person the way, you behave towards the person. This way, a feedback is established and it indicates relationship’s stability. See Measuring Interest Level article on how to take advantage of it.

Miss Right

Let us start with a simplifying condition that we consider interest level of Miss Right in having a long-term relationship with you. If you want the best, you need Miss Right with a positive interest level in you. Thus, we can say
whereRIL, Relationship Interest Level, jis an instantaneous value of the ril function, which expresses her interest level in having a long-term relationship with you. It is an analogy to personal interest level. Just be aware that only the instantaneous values are approximately the same as the functions are not identical. When speaking about a long-term relationship with Miss Right, we can abbreviate to Interest LevelIL.

The abbreviation complies with [2] and [3]. In accordance with a terminology in use:

  • Interest level that is in negative numbers is called negative interest, or low interest level,
  • Interest level that is in positive numbers is called positive interest, or high interest level,
  • Insufficient interest level says she can still choose another man despite high interest level in you – see Damping Factor later

In [2], the Interest Level is given in boundaries from 0% to 100% with the point of no return at 50% - you can transform between both measures with a linear functions.

Even with Miss Right, we can notice that she can stay in a relationship for some time, after her personal level dropped below zero. Accordingly to the Black Box technique, than to search for a clarification, we rather introduce an Inertial Force, if, that is a function of relationship interest level through all the time you know each other.
wl (l as Personal Interest Level) and wf (f as Inertial Force) present weights – how much her personal interest level in you means to her and how much the past relationship with you means to her. For Miss Right, the present is more important than the past.

When she evaluates two men for a relationship, they would never qualify as equal. For a public, she can make some statement to verbalize fairness, so she still would look like a being objective. But for us, there is an important fact – there are no such two men that would have the same RIL for the same woman at the same time..

Other than Right

Other types of women than Miss Right are less or more close to her. With that, the weight of personal interest level changes. For example, it is zero, when it’s about a mercenary. Women are different, some are after you, some are after your money, others dream about being Mrs. Doctor since their childhood, etc. She has some Personal Trait, ptj, which are responsible for assigning particular weights, wi, to her wishes. Their combination affects the final relationship interest level; even your look has some weight. Respective weight determines importance of a particular trait within the interest level. In their maximum and minimum values, the traits have to be in ratio of their weights. This way, their values cannot grow out of bounds to unrealistic values. Mathematically written, it looks like following:As you can see, it is possible to describe her personality with weights, which are used for decision making to achieve a particular goal. A particular set of weights in given ranges describes woman’s personality. Alias, as I shown in the “Dating Is a Game” article, you can view the entire process with numbers and compute the result. Just to get valid inputs with require precision and be able to not let emotions to take control:-) Of course, including costs and possibility to actually do the computation;-)


So far, we refined the equation of relationship interest level motion and we are just one step to finish it – we have to express the influence of your competition. To say, she has some interest levels in other men she meets, and some of these interest levels might actually be in positive numbers. For instance, you might want an engaged, loyal woman that would have higher interest in her partner, or you might want a mercenary, which would prefer the richest one.

The solution is to introduce a Damping Factor function, df, which is a function of all her interest levels in other men, when compared to you. Let df go from 0, no damping, to 1, full damping.And that’s the entire equation of relationship interest level motion, when it comes to you. The greater number, the more she wants it. The lesser number, the more she refuses it.

Related to the relationship interest level, let us state one more important characteristic: an unexpected breakup always raise the interest level [2].


In the "Dating Is a Game" article. I've shown that a model, the one that would cover every woman, would result into a too great number of variables. And as we can see from the equation of interest level motion, it is true. In practice, it is being shown that for a significant number of women, the personal interest level has the greatest weight. Therefore, the techniques, which were developed for Miss Right, would work on a significant number of other women as well – just the efficiency would be lower. Exactly:where w'l is weight that ideal Miss Right gives to personal interest level and a wl goes for a women that we apply the techniques on. To measure your success, the RIL is the desired metric.

For example, with a mercenary the efficiency would be pretty low. So low that she will reject you – in fact, a safety mechanism came into an effect to protect you from bad women.

With any Miss Right, the efficiency would go over 50%, becauseIn accordance with an evaluation of model fitness as it is described in the “Dating Is a Game” article, the given inequality presents a key, why a deviance from the model expresses either a low interest level, or that she is not Miss Right. The efficiency affects the probability of your actions raising her interest level.

Although the weights are noted as constants, they are functions as well. They change dynamically because of the way she is being raised, the society she lives in, etc. They cannot be changed forcibly as a matter of few moments as e.g. sellers of love potions and sure-fire techniques claim.

Per say, she expects a date in a nice café house with obliging personnel and funny companion, whose physical appearance she likes and therefore has positive personal interest level in him. Despite the fact it is relatively easy to met 4 points out of 5, i.e. over 50%, it is clear that her positive personal level won't survive the date, if you'll bore her to the proverbial death. The trick is that you cannot confuse efficiency of strategy and ratio of met initial conditions for a given interval.

Almost in the end, I let my self to repeat once more: if you want the best one, you want Miss Right with high relationship interest level, RIL, in you and therefore you care about her personal level in the first place – PIL.

Other Relationship than the Long-Term One

Yeah, I know. I wrote that even a one night stand is a kind of relationship. So, how would the equation of interest level look like in such case? It would be the same – only another set of weight will be used. Just don’t forget that with some women and e.g. ONS, you’ll always get negative numbers. On the other hand, some women will have a sex with you even despite having their personal interest level in the negative numbers.

To have a long-term relationship with Miss Right,
she must have high interest level in you.

The described principle fits reality into such extent that you can use to express interest level of a man as well. Or you can use it to describe, why she chose red court shoes over blue gum boots. But that I leave upon an attentive reader.

Statistics will be given separately.

Image Notice: Cary Grant and Ingrid Bergman in Alfred Hitchcock’s Notorious movie.

This entry was posted on Tuesday, April 1, 2008 at 6:34 PM and is filed under , . You can follow any responses to this entry through the comments feed .

2 komentářů

I've added the unexpected breakup characteristic (Competition).

April 21, 2008 at 7:35 PM

I have an opinion that hate should not be the bottom bar of attraction level.
Hence a girl can 'hate fuck' a guy she despise over and over again despise bad relationship.

January 18, 2016 at 10:36 AM

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