The psychology of perception of time in elevators

As a technology, elevators were mandatory for having high rise apartments. You really don’t want to climb up 35 flights of stairs to just get home. My experience with elevators (or lifts as they are more commonly called in India) has been rather strange at times and continues to be so. And I am pretty sure, this is something most people also experience. If you look at it with scrutiny, it is not a strange experience per se, but I found it fascinating nonetheless. As the title of the post suggests, it is about how we perceive the passage of time when we are in an elevator. Now, typically, they would take less than a minute, sometimes perhaps 10-20 seconds to traverse the required distance. Now, here I am considering typical apartment buildings which I have lived in. Not the skyscrapers with 100s of floors. The lift takes about 12 seconds, as timed using a stopwatch to reach my floor if there are no other stops. Of course, if there are stops on intervening floors when people get in or get out, this is longer. So this is the minimum possible time for the lift to take this floor, both ways. That is from my floor to the ground floor and from the ground floor to my floor.

The distance between the ground floor and my floor is constant. The lift and its motor produce the same acceleration and hence same terminal velocity, and the time taken is the same (as measured with a chronometer). I used a quantum-temporal-displacement-chronometer to be sure about time measurement. So our experience of this short travel should also be the same. But this is far from the case. Traveling in the lift gives a variety of experiences. But most strongly it affects how we perceive the passage of time during this short journey. Sometimes it is as if the ground floor is touched as soon as you press the 0 button on the control panel, while at other times it seems time itself has slowed down and it is taking centuries to cover that trivial distance. You may look at the panel displaying the current floor several times during these few seconds and yet it somehow feels lift is moving too slowly. And at times when you are not looking at the panel, and are lost in your thoughts, it chimes to indicate the ground floor has arrived. And you are surprised that it took such a short time. So what kind of blackmagicfuckery is this you wonder? That we subjectively experience something entirely different in terms of time perception is nothing new, but in the case of an elevator, it is so much striking and a part of everyday experience.

I have concocted explanations for the two cases one in which we deem the lift going too slowly and one in which we perceive it be too fast. In the first case, when we perceive the lift to be too slow, we are perhaps not thinking about anything else. Our entire cognitive apparatus and sense organs (eyes and ears) are solely focussed on getting to the destination. Hence, we tend to only look at the floors numbers on the display panel again and again. Expecting it to change often, and our expectation time, the way our neurons are firing is much faster than the real-time. The anticipation is that it should go faster whereas it is going at its own pre-determined pace. Hence, there is a cognitive dissonance that we experience as lift going too slowly. This is even more pronounced if we are in a hurry to get somewhere or are already late. I have seen people press the buttons on the control panel again and again in the hope that it will get them there faster, but it doesn’t work that way. Objectively measured the lift will take the pre-determined time to reach its destination. You are only subjectively experiencing that it is taking longer. Perhaps two persons in the same lift will have a  completely different perception of time depending upon their mental states.

Now coming to the other case, in which we experience the time to be too short, perhaps our cognitive system is already too loaded. This is when before entering the lift we are deep in a thought chain that we are processing. In such a scenario, we expect the lift to just take us to the destination once we press the button. Our schema for the elevator is activated, we don’t have to do any cognitive processing once we press the button. The schema, as an automated response shaped by our experiences with elevators and induction, works seamlessly when not interfered with, assuming that the elevator is behaving in its normal manner. I have had experience of an elevator which could close the door as you were trying to enter. It was almost as if the elevator waited like a predator to catch its pray. Some logic circuits in this elevator were fried, and it won’t let you off you when it caught your leg. Or the elevator might itself have a severe case of fear of heights (vertigo?), as told in HHGTG and would not want to travel to heights. But these being extreme cases, most elevators are domesticated and docile, doing the deed they are designed to do depositing and delivering cargo to destinations, despite the draconian ways in which some travellers might treat them.

Coming back to the explanation for the former case, perhaps due to no cognitive load we are trying to screw with the automated schema. We are just running the simulation of the schema for elevators in our minds, and confusing it with the real world out there. Hence there is a cognitive dissonance. We are expecting something in the mind, while we are seeing something in reality. I have also tried this experiment sometimes when this happens. I close my eyes and mentally calculate the amount of time that might have passed and try to predict the floor that I might have reached. I open my eyes to check if I have guessed correctly but most of the times I am incorrect in the guess.

When we have company in the lift, the temporal experience can be altered and can be subjective as well. If you are with a person whom you find attractive or admire, you might feel that the time taken was perhaps too short. On the other hand, if it is somebody whom you find disgusting or un-attractive, the same journey might seem like a lifetime or a life sentence. In this case, perhaps the cognitive system has become completely Epicurean (when it is not?) in its approach and wants to maximise the good times and minimise the not-so-good ones.

But this does not end the discussion of the elevators. Experiments in elevators provide some useful insights in fundamental physics. This is related to the concepts of frames of reference and the so-called equivalence principle. Elevators are used in Gedanken experiments for thinking about the equivalence principle, which later gave rise to the general theory of relativity.

Apple falling inside a box that rests on the Earth. Indistinguishable motion when the appl is inside an accelerated box in outer space.

 

The equivalence principle states that to an observer in a freely falling elevator the laws of physics are the same as in the inertial frames of special relativity (at least in the  immediate neighbourhood of the centre of the elevator). The effects due to the accelerated motion and to the gravitational forces exactly cancel. An observer sitting in an enclosed elevator cannot, if he observes apparent gravitational forces, tell what portion of these correspond to acceleration and what portion to actual gravitational forces. He will detect no forces at all unless other forces (i.e., other than gravitational forces) act on the elevator. In particular, the postulated principle of equivalence requires that the ratio of the inertial and gravitational masses be M_i/M_g = 1. The “weightlessness” of a man in orbit in a satellite is a consequence of the equivalence principle. Pursuit of the mathematical consequences of the  principle of equivalence leads to the general theory of relativity.. –

From Kittel Mechanics – Berkeley Physics Course Volume 1

 

Another fundamental aspect of physics which uses elevators is the notion of inertial and non-inertial frames of reference. An inertial frame of reference is one in which the particle experiences no acceleration (either transitional or rotational).

Our ability to say whether or not a particular reference frame is an inertial frame will depend in a strict sense upon the precision with which we can detect the effects of a small acceleration of the frame. In a practical sense, a reference frame in which no acceleration is observed for a particle believed to be free of any force and constraint is taken to be an inertial frame.

Now an elevator moving with a constant downward acceleration will be no different than the gravity that we experience on the surface of the Earth. No dynamical experiments conducted inside the elevator will ever tell us whether the elevator is moving with constant acceleration or it is stationary at the surface of the Earth. To know what is the actual case we have to go and perform experiments / take observations outside the lift.

Screenshot 2019-07-31 at 8.21.51 PM

Thus the humble lift or elevator has more to offer to you than just taking you from point A to point B in your daily routine.

Explosives or Not

We have earlier seen some quotes from the book The Golem: What You Should Know About Science. There are two companion volumes to this book The Golem Unleashed: What You Should Know about Technology and Dr. Golem: How to think about Medicine. These series of books by Harry Collins and Trevor Pinch provide us with examples from these fields which most of the times are ‘uncontested’. For example in the first volume they discuss about the famous 1920 experimental confirmation of Einstein’s predictions in general relativity by Eddington. This experiment is told as a matter-of-fact anecdote in physics, where petty borders of nationalism could not stop physics and physicists. But in the book, as they show inspite of scanty or almost no positive evidence, Eddington “Concluded” that the predictions were true. This they term “experimenters’ regress”.

The experimenter’s regress occurs when scientists cannot decide what the outcome of an experiment should be and therefore cannot use the outcome as a criterion of whether the experiment worked or not.

The Golem Unleashed pp. 106

In The Golem Unleashed they present us with many examples of this from field of technology. One of the examples is from the Challenger accident which Feynman made famous by courtroom drama. In this case they call the “experimenter’s regress” as “technologist’s regress”.

Recently I read (all further quotes from the same link)an episode in India which would fit in very with these episodes. This is regarding baggage  scanning machines installed at Indian airports. They were brought at 2 crore rupees per unit in 2010. But in August 2011 they failed the tests on tasks they were supposed to do.

The scanners are called in-line baggage inspection systems as they scan bags that go into the cargo hold of the aircraft after passengers check in and hand over their luggage to the airline. They use x-ray imaging and “automatic intelligence” to verify the contents of bags and determine whether they include explosives.

Now one would think that this would be as easy as it gets. Either the scanner detects whether the explosives are present in the baggage or they do not. But it is not as simple as it seems so. Now when the tests were done, the testers found the machines failed.

During the tests, security sources said that a technological specification committee of officials from the IB, RAW, SPG, NSG, BCAS and the civil aviation ministry passed bags containing 500 gm of six kinds of explosives, including PETN and ammonium nitrate, as well as IEDs through these systems. The scanners did not flag any of these bags as suspicious, the sources said.

So after this “failure” the companies which supplied these machines were asked to improve upon the machines or to share the software to recalibrate them. But the companies and interestingly Airport Authortiy of India AAI said that the testing methods were at fault. Now the explosives were passed and the machines did not detect them, then how can companies say that the testing methods were not working?

The machines work on the so called 70:30 principle.

“Though it works on a 70:30 principle, if there is an explosive in the 70 per cent, it will throw up the image of each and every bag that has dangerous substances. We would like to emphasise that the systems supplied and installed by our company at Indian airports are of state-of-the-art technology and are fully compliant with current standards.”

The 70:30 principle refers to the “automatic intelligence” used by Smiths Detection machines to clear 70 per cent of the baggage and reject the rest, according to the Airports Authority of India (AAI). “The machines reject 30 per cent of the baggage, the images of which are then sent to the screener. These systems have automatic intelligence capability and have been tested against a wide range of substances considered dangerous for aircraft. The details and specifications are never disclosed, or else terrorists would understand the software,”

But if anyway machines are doing the job, why not do it 100%? And the funny thing is that they are not sharing the software, which is the main agenda of the proprietary software companies. This is a case where people realize that they are just Users of the software under question. This argument that  “or else terrorists would understand the software” does not hold. They don’t need to if the machine is going to reject a whole lot of bags And in anyway if there are bus/holes in the software, a thousand eyes repair them much faster than a few. And this is The companies further say that

“The technology or physics is that x-ray based system can’t detect explosives, it is only approximate detection of dangerous substances,”

Why is the AAI siding (they are rather defending the companies) with the companies is something worth pondering.

AAI people say “The problem could be due to the sheer ignorance of officers who lacked the skills to test for explosives,”

Still with no unanimity in the testing results, the case truly presents us with a “technologist’s regress.”

Mumbai Locals…

Well Mumbai locals are the life line of the city. But ever wondered how many people can one local train carry? Here I try to estimate the carrying capacity of the local train.

We first want to make an order of magnitude guess for the carrying capacity of the
local train. First let us take the dimensions of one coach of the train.
Let us take the width of the coach to be ~ 3 m or 10 ft. We consider the length of the coach to be
of the order of ~50 ft. Then the floor area that we have in each coach is about 500
sq. ft. We neglect the actual seating arrangement in the local, and consider the
floor area only. We make an assumption that all the people are standing in the coach to
get an upper limit on the carrying capacity of the coach. The passengers are standing
as close to each other as possible. Now we make an estimate of how much area one
person requires to stand. One person would require about 1 sq. ft. area to stand.
Thus in a coach of about 500 sq. ft, about 500 people can stand. Actually there are
9 coaches, and their configuration is as follows. In the Central Railways , a 3-coach
unit is classified as 76, 70, or 72, where 76 is the leading motor coach, 70 is the motor
coach with a pantograph, and 72 is the trailer coach. So a nine-coach train has three
units in the following sequence (for the details and lot of other interesting information about Indian Railways visit here):

(76 -70 – 72)(72 – 70 – 76)(72 -70 – 76)

So in out of 9 coaches some space is lost to the motor coach [3 nos.], the driver
coach [2 nos.] and the eeffective area of the train is reduced. The motor coach has an
area of about 10 ft. and the driver coach of about 5 ft, so about 40 ft is reduced. So
the eeffective number of coaches are 8. Since each coach can hold about 500 people,
8 eeffective coaches will have about 4000 people. We have given about 1 sq. ft. for
one person to stand, but in reality especially in the peak hours the rush is much more
than that, so this estimate will have to be increased. We consider that about 1.5
people can stand in 1 square foot of area. Also the presence of the seats and partitions
in the coaches will reduce the eeffective area usable for standing so we assume that
about 10 % of the entire area is lost in furniture. So the number of people in one coach
450*1:5 = 675. So that in 8 coaches 675*8 = 5400 people can stand. But since not
all people can stand we also have to make a correction for this. About 100 people can
sit in a coach, who effectively take about 2 sqf ft. So about about 150 sq. ft. is taken
by them. So out of the 450 sq we are left with 300 sq ft, so eeffectively 300*1:5 = 450
people are standing. So the total number of people per coach is 450 + 100 = 550. So
that total number of people per train is 550* 8 = 4400. The figures that we get from
Wikipedia show that about 4500-5000 people travel in the local trains during the
peak hours.

So our guess is near about correct!!

This method of analysis is known as solving problem the Fermi way and the problems are Fermi problems. Named after the 20th century physicist Enrico Fermi, such problems typically involve making justified guesses about quantities that seem impossible to compute given limited available information. Fermi was known for his ability to make good approximate calculations with little or no actual data, hence the name.