Tag Archives: comparative advantage

Avoiding an animal on the road

When a bike or car heads towards a squirrel, the squirrel first dodges to one side and then runs away in the other direction. Birds fly directly away from the oncoming vehicle, so stay in front of the vehicle for a few seconds. These behaviours are presumably evolutionary adaptations to avoid predators. For example, the squirrel’s dodge probably misleads a predator to alter course in the direction of the dodge. The larger predator then has more difficulty than a small agile squirrel in switching direction to the opposite side of the dodge.
In avoiding vehicles, these escape patterns are counterproductive. A predator tries to collide with the prey, but a vehicle tries to avoid collision. A squirrel’s dodge confuses the driver or cyclist, who then tries to pass the animal on the opposite side of the initial feint, which is exactly the direction the animal ends up running in. The best way to avoid collision may be to just keep going in a straight line and let the animal dodge out of the way. A constant direction and speed is easy to predict, which lets the animal avoid being in the same place at the same time as the vehicle. Keeping one’s course and speed also avoids accident-prone sharp turns and sudden stopping.
If a predator was smart and knew about the dodging behaviour, then it would go opposite the initial dodge. But then the squirrel would benefit from not switching direction. In response to the squirrel just running in one direction, the predator should run in the direction of the squirrel’s initial movement, etc. This game only has a mixed strategy equilibrium where the squirrel randomises its direction and whether it dodges or not, and the predator randomises its response to the squirrel’s initial movement direction. Dodging takes more energy than just running to one side, so the dodge must have a benefit that outweighs the energy cost, which means that the predator must be less successful when the squirrel dodges. Some factor must make it difficult for the predator to swerve opposite the squirrel’s initial direction. For example, if most prey keep running in one direction instead of feinting, then the predator may be on average more successful when following the initial movement of the prey. The cognitive cost of distinguishing squirrels from other prey must be too large to develop a different strategy for chasing squirrels.
The same game describes dribbling in soccer to avoid a defender. It would be interesting to look at data on what proportion of the time the attacker feints to one side and then moves to the other, as opposed to just trying to pass around the defender in the initial movement direction. It is more difficult for both players to switch than to keep moving in one direction, but presumably the player with the ball finds it relatively more complicated than the defender. In this case, to keep the other player indifferent, each player only has to switch direction less than half of the time, but the defender relatively less frequently. If the attacker feints and the defender does not switch direction, then the defender looks clumsy and the attacker a good dribbler. Reputation concerns of soccer players (who are after all entertainers) may make them switch direction more often than a pure winning motive would dictate.
Similarly, soccer players may use flashy moves like scissor kicks more often than is optimal for winning, because the flashiness makes the player popular with fans.

A residential bike shop business model

There is an empty market niche for a neighbourhood mechanic who accepts a bike in the evening and returns it in the morning. The demand is concentrated almost entirely outside business hours – evening, early morning, weekend. Opening the residential neighbourhood shop at those times would target cyclists whose bike breaks down on the commute from work to home. An overnight fix means they would not miss their next morning’s ride and would not have to haul the bike to a city shop by some other transportation.

Currently the neighbourhood shops I have seen are open during regular business hours, perhaps close a little later and open also on the weekend. I have not checked, but they must be almost customerless in the daytime on weekdays. People go to work or school. I doubt there are enough stay-at-homes who bike enough to require a mechanic’s services frequently. People in the city may visit a city bike shop at lunch, but not a residential neighbourhood one. The local shops seem to be open exactly when the customers are not there.

Fixing a bike takes time, so cyclists leave it in the shop and come back later. It is important which time of the day the bike spends at the mechanic’s. Customers who use their bike a lot and thus need frequent service want the bike available and working mainly during rush hours, because many of them commute with it. A city bike shop open during business hours can accept a bike in the morning, fix it and give it back by the end of the workday. For the commuter, the bike is available both morning and evening. The shop does not need to store the bike overnight, so does not need to rent a large space, saving costs. In a suburban shop, customers could leave their bike one evening and pick it up the next evening, but they could not use their bike for one day’s commute then.

Load sharing between city and suburban bike shops is possible. Mechanics can work in several shops at different times. They can shift to accommodate peak demand, the timing of which differs by shop. The residential neighbourhood shop would get the most customers on the weekend or outside business hours. The city centre would get more on weekdays in the daytime (the cyclists whose bike breaks down on the way to work).

Yoga teachers are not using their comparative advantage

A substitute good for yoga classes is yoga videos on the web. The advantages of following a video over going to class are that you can do it at home, at any time that suits you, can skip or repeat parts, it is free, clothes are optional and the selection of teachers and classes is much larger. If you prefer to do yoga in a group, you can get some friends together, but this reduces the time flexibility and a large group needs a large room. The advantage of a yoga teacher is that they can correct your posture mistakes, either by telling you (doable in a video call based yoga class) or by physically moving your limbs to a different posture. A teacher may also be a commitment device – if you have trouble motivating yourself to exercise, then someone’s oversight may substitute for willpower.

Most yoga teachers seem to not use their advantage, meaning they just instruct in front of the class and don’t correct people’s postures. I have seen this in online yoga videos taken in actual classes and experienced it in most classes I have attended. I have tried about 30 yoga teachers overall.

Maybe some students do not want to be touched for physical posture correction or the yoga teacher has a phobia of touching, or (especially in the US) there is a fear of litigation related to any physical contact. Even telling someone about their wrong posture may be psychologically difficult (people may be taught that “if you have nothing good to say, don’t say it”), or a student not used to criticism may react negatively to it, however gentle and well-intentioned it is. Maybe the philosophy is “whatever is, is right” and that yoga is so individual that there is no such thing as wrong posture. I disagree on this, having sometimes caused myself slight injury by overextending joints in wrong postures (that went uncorrected).

Smarter people have a comparative advantage in theory

Theory research requires figuring out the result and how to prove it, and then writing these down. Empirical research requires the same, plus running the experiment or analyzing the data in order to prove the result. This requires relatively more time and less insight. If the production function of empirics requires in its input mix more time per unit of insight than the production function of theory, then smarter people have a comparative advantage in theory. They are endowed with more insight, but everyone has the same amount of time.
The amounts of theory and empirical research produced per unit of insight need not be related in any way for the above comparative advantage result.
Based on comparative advantage, I should switch to empirical research 🙂
Some empirical research methods are quite simple, but modern theory requires complicated math. Due to this, empirical research requires more time per unit of methods knowledge in its input mix. People with a stronger methodological background (better education) thus have a comparative advantage in theory. This suggests graduates of universities with more (advanced) coursework should be more likely to do theory.