Post No.: 0622
We’ve been learning throughout this blog that our brains don’t interpret the physical world or reality objectively – there are individualised interpretations of the world and our brains interpret the world according to our own personal expectations, prior knowledge and beliefs (our mental model). What we sense through our senses and perceive in our minds depend highly on what we’re presently focused on, our past experiences and preconceptions, and ultimately how we interpret the received signals in our brains. (There is likely scientific realism, but we naturally view the world with subjective relativism.)
Bottom-up processing is when sensory data gathered from environmental stimuli directs our cognition and behaviour (so sensory information directs cognition, or raw information processing). Top-down processing is when pre-existing knowledge, goals, expectations and memories already inside our minds are used to make sense of environmental stimuli and influence our experiences and behaviour (so cognition constructs perception, or heuristic cognitive processing). And top-down processing trumps bottom-up processing.
The Ames room and hollow-face illusions show us that our brains interpret the world according to our existing schemas and expectations – assumptions regarding rectangular room shapes and convex faces in these cases.
Strangely, people with schizophrenia will actually see the concave face for what it is, which may suggest that this contributes to their sense of disassociation from reality – which would be ironic if true because they would be the ones who are actually seeing reality for what it is in this case! This also philosophically poses the question – is something a disorder or simply a difference in perspective? Woof.
Some other studies however show that people with schizophrenia are more likely to jump to conclusions after seeing only a very small number of observations, and they’ll be quite certain about these conclusions too, which may help explain the delusions and paranoia. They may hold highly distorted prior beliefs.
Well everybody holds some degree of distorted prior beliefs (and/or problems with learning or decision strategies) because no one is a ‘perfect perceiver’ – no one has a ‘perfect brain’ (whatever that is).
Our eyes, for example, don’t see everything, even if we concentrate on seeing. (It’s even worse if we don’t though!) The only part that’s really in focus is within the fovea region, with the rest filled in with assumptions (e.g. that backgrounds are coloured more uniformly than they might be) based on our prior experiences. We can even fail to notice that glaucoma or cataracts are developing in our peripheral vision until it gets quite bad because the brain does too good a job at filling in the missing picture with assumptions that we don’t realise are merely assumptions. This is why we must take regular eye tests!
The same with people’s hearing and missing certain frequencies over time without realising it. ~17.4kHz is said to be only audible by young people. (As a dog I can hear it fine but I’m sure that older dogs gradually lose their hearing too.)
We fill in our sensory perception with assumptions when we proofread our own work and see it as grammatically correct when it isn’t. This is because it’s harder to see our own mistakes because we know what we mean. That’s why it best get other people to proofread our work, or least leave some time between reads so can see it with relatively ‘fresh eyes’ again.
When dreaming, we might feel the sensation of falling from a height, but of course we’re not falling anywhere because we’re firmly in bed. It just highlights the power of the mind is such that one can even viscerally feel something simply because one thinks or believes it (e.g. retching over perfectly fine food because of prior conceptions or suggestions that it’s yucky). It again shows us that most of experience and existence is a mental and subjective, not objective or one-to-one physical, construct.
Hallucinations involve no credible external input that leads to the things that are being imagined i.e. they’re mental fabrications that have no consistent basis on what’s environmentally sensed at all. This could be as a result of brain damage, a disorder or psychosis-inducing drugs. The difference here is that they can be created virtually wholesale within one’s mind. It can however be a fine line between hallucination and pareidolia (the erroneous perception of patterns, objects or meanings from stimuli). To minimise the chances of interpretation errors – don’t take drugs recreationally, get enough sleep and reduce your stress. Good decisions are seldom made otherwise.
When people are hypnotised to temporarily forget a portion of their memories, they spontaneously rationalise and fabricate false memories or facts to fill in the gaps in them in order to present a coherent and complete story – so rather than simply admit that one has somehow forgotten about a portion of one’s own life, one will tend to automatically come up with some fabricated memories or ‘facts’ that sound plausible and coherent.
Time appears to slow down during extremely stressful moments, such as the milliseconds before we have a vehicle accident. However, this (obviously) isn’t because time does actually slow down but because we lay down and keep more memories for the event because it was a salient event for us, and the density of these memories that can be recalled for that event is interpreted as ‘time had slowed down’. It’s probably why the years seem to run slower when people are younger than when older – when younger, more stuff seemed novel and salient and so more memories are laid down and kept per month of people’s lives (over the age of ~2 years). When older, the routines from year-to-year likely follow a relatively more similar pattern and so the years seem less distinct from each other. This suggests trying to maintain novelty in your life to make it seem like it’s lasting longer!
If you’ve divorced and changed jobs within the last 3 years then 5 years ago seems longer ago than if nothing had changed much in your life during this same span. Time also flies when you’re having fun. The proposed ‘holiday paradox’ is the way that a nice holiday seems to fly by at the time, yet feels long when we reminisce on it. This is probably to do with the difference between our experiencing self and remembering self.
Many physicists currently think that our intuitive perception of time is fundamentally an illusion. Under a ‘block universe’, there’s 4-dimensional spacetime, and time is a dimension similar to the 3 spatial dimensions (which are typically called height, width and depth). Thus the past, present and future all simultaneously exists – just like here, what’s to your left and what’s to your right all simultaneously exists in space. It’s all relative, and so we give false importance to now or the present moment. We can only perceive one slice of time at a time though. We psychologically experience the flow of time and causation but it’s not fundamentally real. There’s a local sense of time but you could travel near the speed of light (and lower your gravitational potential) and return back to find that your own children are now older than you!
This block universe model is supported by the theory of relativity, which we know isn’t a complete theory of everything; albeit it’s empirically the best theory we have so far to explain phenomena above the atomic level. It can depend on how we define time too – is it this subjective experience itself of moments moving forwards that probably all of us intuitively regard as ‘time’? And just because it’s subjective, does that make it any less real to us? (The same with the notion of free will?) We live as particular creatures and how our perceptions evolved, and what our perceptions feel like matter for our well-being and practical life (e.g. accepting that we cannot go back in time and only the present can be affected).
Quantum mechanics and black holes make us question whether space and time are even fundamental root aspects of reality? According to current understanding, time didn’t exist until the Big Bang (or shortly before it but after the ‘initial singularity’).
Anyway, our sensory, attentional and mental working capacities are limited. Our brains are more like guessing machines that are constantly unconsciously forming hypotheses (conditional probabilities) according to the received sensory data. It’s about interpreting or piecing together a reasonable construction of the received sensory data. We constantly unconsciously make inferences about the causes of what we perceive. When sensory data is lacking or highly ambiguous (i.e. when there’s strong uncertainty), we rely even more on our prior beliefs (our preconceptions, assumptions, stereotypes) to form an interpretation or view.
‘Mental models’ are our thought processes about how something works in the real world and – although they’re often based on incomplete or oversimplified information, past experiences, inferences and intuitions – they help shape behaviour and even influence what we pay attention to in complicated situations. They define how we approach and solve problems and guide us by subconsciously and selectively filtering and interpreting new information (via confirmation biases, which results in a general inertia in changing our beliefs and therefore our habits and behaviours).
Our mental or internal models can change though, but they require concerted conscious effort – try breaking down your old preconceptions whilst simultaneously replacing them with new supported facts. As just a few examples, our mental models include – how the laws of physics work, how the politico-economic system works in our country, and if we don’t hear from a fluffy friend for a while then our mind produces some models/simulations about what could’ve possibly happened. Sometimes these models hold contradictions and inconsistencies that won’t be apparent unless they’re directly brought together to allow us to compare them side-by-side.
Overall, these heuristics, biases and predictions are a highly efficient way to live in an incredibly noisy world – for instance when anticipating dangers that are too fast to rely purely on the received sensory data (hence we tend to assume that all eyes are looking at us when our backs are facing others!) But they do occasionally fail to give the correct or optimal answer in quite serious ways, like when we form superstitious beliefs for assuming that something preceding something else must have necessarily caused the latter, or when people escalate violence when they hit each other back harder for assuming that they didn’t hit the other party as hard as they think they did. However, our mental models can update, our brains are malleable, and can adapt to a large extent if given enough desire, education and experience.
We are good at filtering out irrelevant information and good at taking into account context and expectations, which in turn shapes our appreciation of a situation. Meanwhile, current artificial intelligences suffer from the ‘frame problem’, where they don’t know what information is relevant to solve a problem. They take all information and instructions literally too.
So our organic brains work cognitively efficiently most of the time, but a drawback is that this natural filtering can lead to ascribing disproportionate bias to certain contextual data over others (e.g. we tend to assume that positive characteristics cluster, such as handsomeness and innocence, neater handwriting and a better essay content, or teams in black shirts are more aggressive and unfair compared to teams in white).
We find using heuristics or cognitive shortcuts extremely instinctive, possibly because it overall saves energy to stereotype or (over)generalise and/or it’s better to err on the side of caution as a broad rule. (Post No.: 0448 explains more.) Yet obeying these cognitive shortcuts can lead to some arguably irrational behaviours – some of which are okay or neutral in consequence (e.g. sex is pleasurable even when it’s not used for procreation), and some of which are pernicious (e.g. comfort eating even when we don’t need the calories and there’s no foreseeable risk of an impending famine), depending on the environment.