Gaveen Prabhasara

System Interrupts and Caffeine

· Gaveen Prabhasara

There’s a concept in computing called an interrupt signal, which essentially works by disrupting the current focus of a processor. An interrupt signal can be based on hardware (e.g., a key press from a keyboard) and software (e.g., a system call invocation to create a new file).

It’s not surprising that we have such terminology because we also function using interrupt signals. The human analogy of hardware interrupts could be an example of feeling pain from a pinprick. Our equivalent of a software interrupt could be choosing your responses in a social interaction.

If you read my previous post "Neurodiversity" or know anything about neurodivergent people in general, you probably know their hardware and software function somewhat differently than the average person. It’s still based on the latest Homo sapiens sapiens hardware platform running neuron (and glial cell) based processing units. Only the human units aren’t uniform or produced identically—even in the same assembly line. Humanity has utilized this diversity to its advantage—to adapt, survive, and thrive under ever-changing conditions, effectively becoming the dominant species on this backspace planet called Earth.

This post comes with the disclaimer that I’m not using the analogy of system interrupts (or anything else for that matter) to perpetuate the ignorant, offensive, and harmful idea of autistic/neurodivergent people as emotionless, tactless robots incapable of empathy—or something less than other humans, and the other R word unspoken. I’m using the analogy because it works universally for all of humanity.

Depending on who you ask, the number of senses in a human can vary. We know the primary external senses as touch, smell, taste, hearing, and vision. Interoception is another collection of senses that functions inwards (i.e., a collection of senses that encompasses areas regulating aspects such as hunger, thirst, waste-processing, temperature regulation, heart function, immunity response, etc.). I haven’t studied biology enough to not embarrass myself if I continue further. So, I’ll get to the point. Being neurodivergent means a person will have some sensory experiences that aren’t considered typical. And when I mean different, I don’t mean one extreme. It means anything above, below, and adjacent to what is perceived as typical.

At this point, I also have to point you to the potential pitfall: Oh, I have that too. That doesn’t mean you’re neurodivergent. We’ve talked about this before. Neurodivergent people are human. Therefore, all the experiences I’m about to mention are humanly possible. If you share many things with neurodivergent people, you can look into if you are too—if that’s something you’d want. But please don’t use that as a tool to try and invalidate someone else’s lived experience. Now, let’s get back on track, shall we?

Sensory differences outside the perceived typical thresholds are not inherently deficits, merely a difference in how they are experienced. However, some neurodivergent people can be disabled because of these differences. There is nothing disgraceful about it. Even neurodivergent people who aren’t generally considered disabled still can have difficulties dealing with these differences in sensory sensitivities. Neurotypical people also can have different individual sensitivities and disabilities.

If you are wondering if I have differences in sensory sensitivities and what that has to do with system interrupts, I’m glad (that I can assume) you asked. Let’s analyze an example from my life. As far as I can tell, my hearing sensitivity differs in a few ways. I’ve always been very musical. I have good pitch, and I was one of the people who other students came to get their musical instruments tuned in the school orchestra. Music has more meaning to me than your average person. The experience I get from music (that holds my interest) has a particular level of intensity. It triggers emotional responses, and I can listen to tracks on repeat until my emotions induce tears. And this isn’t a one-off either. I can come to the same song days, months, or years later and enjoy it that passionately again. So far, it’s nothing too tangential, right?

Some people can have the kind of sensitivity to cause pain or discomfort. Luckily, my hearing sensitivity isn’t usually debilitating. While loud sounds don’t particularly overwhelm me, I have noticed my threshold for comfort is lower. I’m always the person who turns down the car audio or TV volume. But I can also be in a flow state of mind inside an entire data center full of loud servers and cooling system fans. I can be in the zone while blasting BYOB by System of a Down on repeat—because I perceive some type/form of regularity I can process. Being able to observe and process patterns everywhere is also another well-known neurodivergent trait.

I can also hear lower levels comfortably and clearly. As a child, I could always clearly hear the power-on state of a muted CRT TV in a house from the outside. I can usually recognize distant sounds before people around me can perceive them. However, irregular (or, I like to call it, uneven) sounds are my kryptonite. Trying to filter out the sound of people talking is my Achilles heel.

While I have no trouble processing and tolerating sounds beyond my comfort thresholds but within my pain thresholds, I get overwhelmed by sound profiles outside my evenness/regularity thresholds. I’m rendered useless for cognitively taxing workloads when people talk around me. The lowest whispers and the loudest obnoxious talking will equally and certainly interrupt my processing. A mildly overenthusiastic drum beat in a lo-fi track will yank away my attention. My productivity will invariably drop almost to zero. However, my emotional response will be nuanced.

I’m sympathetic towards people who are loud out of necessity or have trouble regulating their speaking volume. But, I dislike people who use loudness as a social behavioral power move. All of these scenarios cause me difficulties equally. But my emotional response is different because I’m capable of behavioral nuance. A neurodivergent person with other co-occurring disabilities might not be able to communicate why they are overwhelmed or that they are overwhelmed. Another person with different sensory thresholds might not react as gracefully to the same sensory interrupts. I’m but a single example of a group of people as diverse as the totality of humanity.

As an individual, I also have exceptions to being overwhelmed by uneven sounds. For example, if I’m not required to think nontrivial thoughts, I can handle it just fine. If I’m engaged in a Special Interest activity, I might not become overwhelmed even while thinking. This is because special interests have higher priorities for neurodivergent people. Because of the intense focus and engagement, neurodivergent people may not even register system interrupts such as hunger and thirst, let alone uneven sounds. They can get externally interrupted, but they won’t like it.

Special Interests are a topic for another day. I just mentioned it as an example of how priority is another aspect of interrupts. When the priority of an interrupt changes, so does the perceived sensitivity. For example, an alarm was beeping nearby while I typed this post. I had effectively filtered it out. However, as soon as I finished the first draft and switched to editing mode, the beeping became so distracting I had to wear headphones to block it.

The above examples are only about my hearing sense. Neurodivergent people have different differences in other sensory sensitivities as well. For example, the sensitivity differences regarding touch could be on properties like texture, temperature, motion, shape, etc. The same holds true for food. But food also has sensory components like smell, look, taste, and sound. How different neurodivergent people process and handle different senses and emergent sensory properties associated with them (e.g., crunchiness, fizziness, etc.) can be vastly different. While some neurodivergent people avoid new sensory experiences (e.g., autism stereotype) because of sensitivities, some can be seeking new experiences (e.g., ADHD stereotype). Some might have both traits. Therefore, if someone is neurodivergent, they might have sensory and sensitivity differences even without noticing them. This is why listening to other neurodivergent people can be so helpful in processing your own experiences.

I’ll share another anecdotal analysis. I like energy drinks such as Red Bull and Monster. I’m not addicted to them and can go months without craving them. But once that tried and tested sensory experience comes to my attention, I need to consciously regulate my consumption, just like any other food/beverage I like. Since I know I can safely expect a consistently enjoyable experience and am a grown man who can buy whatever drink I want, I tend to keep going for familiar sensory seeking via unhealthy beverage consumption until I consciously cut myself off. I only know it’s not an addiction/abuse because it takes only a mental note to break the streak. Luckily, through my upbringing and personal choices, I’ve stayed away from truly addictive substances. Not everyone gets to be lucky like that. In a painful existence, even a harmful reprieve can become a solace. Hurt can distract you from pain—and vice versa. This is why you need caring people around you.

Anyway, my caffeine anecdote isn’t finished yet. It has another chapter with a long-running plot to complete the story while touching on another aspect of probably neurodivergent differences. I got on the caffeine train by the virtue of working in tech. Sleep deprivation and caffeine went hand in hand during the early years of my career. Coffee was the prescription veterans handed over to newcomers. Then, the energy drink boom happened in Sri Lanka. Red Bull became mainstream here. So did the beloved and discontinued local attempt, Wild Elephant, and others. Fast forward a decade or so, and I thought I was living on caffeine during project deadlines. My worst caffeine intake was during the data center certifications in 2022. Since I was the key person, the certification audit week saw me chugging a (sugar-free) Red Bull can for office hours and another if I had to work late. But I knew it was unhealthy. And I immediately stopped as soon as the audit closing meeting wrapped.

The funny thing is, now I know caffeine does little for me. It’s not because I’ve built a tolerance. I only consumed caffeine because I wanted to stay awake. I also didn’t have a caffeine withdrawal whenever I stopped. I had an inkling it wasn’t doing much for me when I tried alternative sensory experiences to cut back on drinking sugary fizzy drinks. Apparently, what was keeping me awake was my sensory seeking. With coffee, the number of coffee cups (for which I have no intention of testing the limits) or the fact that it was regular or decaf didn’t seem to make a noticeable difference for me. Drinking a can of Red Bull or Monster doesn’t affect falling asleep or my sleep quality if I want to sleep. The final straw was finding other sensory-seeking interrupts that could keep me awake. The current list goes like this: hot green tea, isotonic drinks, fizzy drinks, simple plain soda (i.e., water + carbonation and nothing else), and chilled water. Yes, that’s right. Chilled water and sparkling water are as effective in keeping me awake as a can of Red Bull/Monster. Please insert an imaginary facepalm emoji here.

I didn’t know I was neurodivergent back when I started the experiment with energy drink alternatives. I put the two and two together about caffeine only a couple of months ago when I realized caffeine having little or inverse effect was not that uncommon among neurodivergent people. For example, some people with ADHD find it easier to fall asleep after they consume caffeine. As far as I know, it’s not a well-documented or researched effect yet. But hearing from fellow neurodivergent people helped me to break the illusion that I needed caffeine to stay awake. It helped me to make a positive change in my habits with a better understanding of myself.

Since we’re nearing the end of this post, let me recap my use of the analogy of system interrupts. Neurodiversity (including Autism) is not an incomplete puzzle with missing pieces. It’s a natural state of life. I hope the system interrupts analogy gives you a better understanding—even by just a little bit. Neurodivergent people are also people—like you. But they experience and process the world differently. Therefore, they can respond and behave to the interrupts of the world in ways that are different from other people.

So what’s the moral here? What do I hope you remember from this post? I hope you remember to accommodate neurodivergent people you come across in life and treat them with the same dignity and respect you should be extending to all human beings. Their differences aren’t meant to inconvenience you. It’s their natural existence. Their existence is no more taboo and shameful than all of humanity. Acknowledging and showing solidarity with neurodivergent people doesn’t take anything away from you. It will only help to enrich the human existence on this Pale Blue Dot, and someday even beyond.