Mind Hacks™: Tips & Tools for Using Your Brain (3 page)
Read Mind Hacks™: Tips & Tools for Using Your Brain Online
Authors: Tom Stafford,Matt Webb
Tags: #COMPUTERS / Social Aspects / Human-Computer Interaction
The book is divided into 10 chapters, organized by subject:
- The question is not just “How do we look inside the brain?” but “How do we talk
about what’s there once we can see it?” There are a number of ways to get an idea about
how your brain is structured (from measuring responses on the outside to taking pictures
of the inside) — that’s half of this chapter. The other half speaks to the second
question: we’ll take in some of the sights, check out the landmarks, and explore the
geography of the brain.
- The visual system runs all the way from the way we move our eyes to how we
reconstruct and see movement from raw images. Sight’s an important sense to us; it’s
high bandwidth and works over long distances (unlike, say, touch), and that’s reflected
in the size of this chapter.
- One of the mechanisms we use to filter information before it reaches conscious
awareness is attention. Attention is sometimes voluntary (you can pay attention) and
sometimes automatic (things can be attention-grabbing) — here we’re looking at what it
does and some of its limitations.
- Sounds usually correspond to events; a noise usually means something’s just
happened. We’ll have a look at what our ears are good for, then move on to language and
some of the ways we find meaning in words and sentences.
- It’s rare we operate using just a single sense; we make full use of as much
information as we can find, integrating sight, touch, our propensity for language, and
other inputs. When senses agree, our perception of the world is sharper. We’ll look at
how we mix up modes of operating (and how we can’t help doing so, even when we don’t
mean to) and what happens when senses disagree.
- This chapter covers the body — how the image the brain has of our body is easy to
confuse and also how we use our body to interact with the world. There’s an illusion you
can walk around, and we’ll have a little look at handedness too.
- We’re not built to be perfect logic machines; we’re shaped to get on as well as
possible in the world. Sometimes that shows up in the kind of puzzles we’re good at and
the sort of things we’re duped by.
- The senses give us much to go by, to reconstruct what’s going on in the universe. We
can’t perceive cause and effect directly, only that two things happen at roughly the
same time in roughly the same place. The same goes for complex objects: why see a whole
person instead of a torso, head, and collection of limbs? Our reconstruction of objects
and causality follow simple principles, which we use in this chapter.
- We wouldn’t be human if we weren’t continually learning and changing, becoming
different people. This chapter covers how learning begins at the level of memory over
very short time periods (minutes, usually). We’ll also look at how a few of the ways we
learn and remember manifest themselves.
- Other people are a fairly special part of our environment, and it’s fair to say our
brains have special ways of dealing with them. We’re great at reading emotions, and
we’re even better at mimicking emotions and other people in general — so good we often
can’t help it. We’ll cover both of those.
The following typographical conventions are used in this book:
Italics
- Used to indicate URLs, filenames, filename extensions, and directory/folder names.
For example, a path in the filesystem will appear as
/Developer/Applications
.
Color
- The second color is used to indicate a cross-reference within the text.
You should pay special attention to notes set apart from the text with the following
icons:
This is a tip, suggestion, or general note. It contains useful supplementary
information about the topic at hand.
This is a warning or note of caution, often indicating that your money or your privacy
might be at risk.
This is an aside, a tangential or speculative comment. We thought it interesting,
although not essential.
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Mind Hacks
by Tom
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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.
- Daniel Dennett has written a brief essay called “Cognitive Science
as Reverse Engineering” (
http://pp.kpnet.fi/seirioa/cdenn/cogscirv.htm
) in which he discusses the philosophy of this approach to mind. - A psychologist called Daryl Bem formalized this in “self-perception
theory.” He said “Individuals come to know their own attitudes, emotions and internal
states by inferring them from observations of their own behavior and circumstances in
which they occur. When internal cues are weak, ambiguous, or uninterpretable, the
individual is in the same position as the outside observer.” Bem, D. J., “Self
Perception Theory.” In L. Berkowitz (ed.),
Advances in Experimental Social
Psychology
, volume 6 (1972).
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.
- The EEG technique is well understood and has been in use for many decades.
Patterns of electrical activity corresponding to different states are now well-known:
sleep, epilepsy, or how the visual cortex responds when the eyes are in use. It is
from EEG that we get the concepts of alpha, beta, and gamma waves, related to three
kinds of characteristic oscillations in the signal. - Great time resolution. A reading of electrical activity can be taken every few
milliseconds, so the brain’s response to stimuli can be precisely plotted. - Relatively cheap. Home kits are readily available. OpenEEG (
http://openeeg.sourceforge.net
), EEG for the rest of us, is a project to develop low-cost EEG devices,
both hardware and software.
- Poor spatial resolution. You can take only as many readings in space as electrodes
you attach (up to 100, although 40 is common). Even if you are recording from many
locations, the electrical signals from the scalp
don’t give precise information on where they originate in the brain. You
are getting only information from the surface of the skull and cannot perfectly infer
what and where the brain activity was that generated the signals. In effect this means
that it’s useful for looking at overall activity or activity in regions no more
precise than an inch or so across.
— Myles Jones & Matt Webb
