Read Mind Hacks™: Tips & Tools for Using Your Brain Online
Authors: Tom Stafford,Matt Webb
Tags: #COMPUTERS / Social Aspects / Human-Computer Interaction
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Mind Hacks
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It’s never entirely true to say, “This bit of the brain is solely responsible for
function X.” Take the visual system
[
Understand Visual Processing
]
, for instance; it runs through many
varied parts of the brain with no single area solely responsible for all of vision. Vision is
made up of lots of different subfunctions, many of which will be compensated for if areas
become unavailable. With some types of brain damage, it’s possible to still be able to see,
but not be able to figure out what’s moving or maybe not be able to see what color things
are.
What we can do is look at which parts of the brain are active while it is performing a
particular task — anything from recognizing a face to playing the piano — and make some
assertions. We can provide input and see what output we get — the black box approach to the
study of mind. Or we can work from the outside in, figuring out which abilities people with
certain types of damaged brains lack.
The latter, part of neuropsychology
[
Neuropsychology, the 10% Myth, and Why You Use All of Your Brain
]
, is an important tool for
psychologists. Small, isolated strokes can deactivate very specific brain regions, and also
(though more rarely) accidents can damage small parts of the brain. Seeing what these people
can no longer do in these pathological cases, provides good clues into the functions of those
regions of the brain. Animal experimentation, purposely removing pieces of the brain to see
what happens, is another.
These are, however, pathology-based methods — less invasive techniques are available.
Careful experimentation — measuring response types, reaction times, and response changes to
certain stimuli over time — is one such alternative. That’s cognitive psychology
[
Find Out How the Brain Works Without Looking Inside
]
, the
science of making deductions about the structure of the brain through reverse engineering from
the outside. It has a distinguished history. More recently we’ve been able to go one step
further. Pairing techniques from cognitive psychology with imaging methods and stimulation
techniques
[
Electroencephalogram: Getting the Big Picture with EEGs
through
Transcranial Magnetic Stimulation: Turn On and Off Bits of the Brain
]
, we can
manipulate and look at the brain from the outside, without having to, say, remove
the skull and pull a bit of the cerebrum out. These imaging methods are so important and
referred to so much in the rest of this book, we’ve provided an overview and short explanation
for some of the most common techniques in this chapter.
In order that the rest of the book make sense, after looking at the various neuroscience
techniques, we take a short tour round the central nervous system
[
Get Acquainted with the Central Nervous System
]
, from the spine,
to the brain
[
Tour the Cortex and the Four Lobes
]
, and then down to the individual neuron
[
The Neuron
]
itself. But what we’re really interested in is how the
biology manifests in everyday life. What does it really mean for our decision-making systems
to be assembled from neurons rather than, well, silicon, like a computer? What it means is
that we’re not software running on hardware. The two are one and the same, the physical
properties of our mental substrate continually leaking into everyday life: the telltale sign
of our neurons is evident when we respond faster to brighter lights
[
Why People Don’t Work Like Elevator Buttons
]
, and our
biological roots show through when blood flow has to increase because we’re thinking so hard
[
Detect the Effect of Cognitive Function on Cerebral Blood Flow
]
.
And finally take a gander at a picture of the body your brain thinks you have and get in
touch with your inner sensory homunculus
[
Build Your Own Sensory Homunculus
]
.
How do you tell what’s inside a black box without looking in it? This is the challenge
the mind presents to cognitive psychology.
Cognitive psychology
is the psychology of the basic mental
processes — things like perception, attention, memory, language, decision-making. It asks the
question, “What are the fundamental operations on which mind is based?”
The problem is, although you can measure what goes into someone’s head (the input) and
measure roughly what they do (the output), this doesn’t tell you anything about what goes on
in between. It’s a black box, a classic reverse engineering problem.
1
How can we figure out how it works without looking at the code?
These days, of course, we can use neuroimaging (like EEG
[
Electroencephalogram: Getting the Big Picture with EEGs
]
, PET
[
Positron Emission Tomography: Measuring Activity Indirectly with PET
]
, and
fMRI
[
Functional Magnetic Resonance Imaging: The State of the Art
]
) to look inside the head at the brain, or use information on anatomy and
information from brain-damaged individuals
[
Neuropsychology, the 10% Myth, and Why You Use All of Your Brain
]
to inform how we think
the brain runs the algorithms that make up the mind. But this kind of work hasn’t always
been possible, and it’s never been easy or cheap. Experimental psychologists have spent more
than a hundred years refining methods for getting insight into how the mind works without
messing with the insides, and these days we call this cognitive psychology.
There’s an example of a cognitive psychology–style solution in another book from
the hacks series,
Google Hacks
(
http://www.oreilly.com/catalog/googlehks
). Google obviously doesn’t give access to the algorithms that run its searches,
so the authors of
Google Hacks
, Tara Calishain and Rael Dornfest, were
forced to do a little experimentation to try and work it out. Obviously, if you put in two
words, Google returns pages that feature both words. But does the order matter? Here’s an
experiment. Search Google for “reverse engineering” and then search for “engineering
reverse.” The results are different; in fact, they are sometimes different even when
searching for words that aren’t normally taken together as some form of phrase. So we might
conclude that order does make a difference; in some way, the Google search algorithm takes
into account the order. If you try to whittle a search down to the right terms, something
that returned only a couple of hits, perhaps over time you could figure out more exactly how
the order mattered.
This is basically what cognitive psychology tries to do, reverse engineering the basic
functions of the mind by manipulating the inputs and looking at the results. The inputs are
often highly restricted situations in which people are asked to make judgments or responses
in different kinds of situations.
How many words from the list you learned
yesterday can you still remember? How many red dots are there? Press a key when you see an
X appear on the screen
. That sort of thing. The speed at which they respond,
the number of errors, or the patterns of recall or success tell us something about the
information our cognitive processes use, and how they use it.
A few things make reverse engineering the brain harder than reverse engineering
software, however.
Biological systems are often complex, sometimes even chaotic (in the technical sense).
This means that there isn’t necessarily a one-to-one correspondence in how a change in input
affects output. In a logic-based or linear system, we can clearly see causes and effects.
The mind, however, doesn’t have this orderly mapping. Small things have big effects and
sometimes big changes in circumstance can produce little obvious difference in how we
respond. Biological functions — including cognition — are often supported by multiple processes.
This means they are robust to changes in just one supporting process, but it also means that
they don’t always respond how you would have thought when you try and influence them.
People also aren’t consistent in the same way software or machines usually are. Two
sources of variability are noise and learning. We don’t automatically respond in the same
way to the same stimulus every time. This sometimes happens for no apparent reason, and we
call this randomness
noise
. But sometimes our responses change for a
reason, not because of noise, and that’s because the very act of responding first time
around creates feedback
that informs our response pattern for the next time (for example, when you get a
new bike, you’re cautious with your stopping distance at first, but each time you have to
stop suddenly, you’re better informed about how to handle the braking next time around).
Almost all actions affect future processing, so psychologists make sure that if they are
testing someone the test subject has either done the thing in question many times before,
and hence stopped changing his response to it, or he has never done it before.
Another problem with trying to guess how the mind works is that you can’t trust people
when they offer their opinion on
why
they did something or
how
they did it. At the beginning of the twentieth century,
psychology relied heavily on introspection and the confusion generated led to the movement
that dominated psychology until the ’70s: behaviorism.
Behaviorism
insisted that we treat only what we can reliably measure as part of psychology and excluded
all reference to internal structures. In effect we were to pretend that psychology was just
the study of how stimuli were linked to outputs. This made psychology much more rigorous
experimentally (although some would argue less interesting). Psychology today recognizes the
need to posit mind as more than simple stimulus-response matching, although cognitive
psychologists retain the behaviorists’ wariness of introspection. For cognitive
psychologists, why you think you did something is just another bit of data, no more
privileged than anything else they’ve measured, and no more likely to be right.
2
Cognitive psychology takes us a long way. Many phenomena discovered by cognitive and
experimental psychology are covered in this book — things like the attentional blink
[
Avoid Holes in Attention
]
and state-dependent
recall
[
Boost Memory Using Context
]
.
The rigor and precision of the methods developed by cognitive psychology are still vital,
but now they can be used in tandem with methods that give insight into the underlying brain
structure and processes that are supporting the phenomenon being investigated.
EEGs give you an overall picture of the timing of brain activity but without
any fine detail.
An
electroencephalogram
(EEG) produces a map of the electrical
activity on the surface of the brain. Fortunately, the surface is often what we’re
interested in, as the cortex — responsible for our complex, high-level functions — is a thin
sheet of cells on the brain’s outer layer. Broadly, different areas contribute to different
abilities, so one particular area might be associated with grammar, another with motion
detection. Neurons send signals to one another using electrical impulses, so we can get a
good measure of the activity of the neurons (how busy they are doing the work of processing)
by measuring the electromagnetic field nearby. Electrodes outside the skull on the surface
of the skin are close enough to take readings of these electromagnetic fields.
Small metal disks are evenly placed on the head, held on by a conducting gel. The range
can vary from two to a hundred or so electrodes, all taking readings simultaneously. The
output can be a simple graph of signals recorded at each electrode or visualised as a map of
the brain with activity called out.
— Myles Jones & Matt Webb