Read Mind Hacks™: Tips & Tools for Using Your Brain Online
Authors: Tom Stafford,Matt Webb
Tags: #COMPUTERS / Social Aspects / Human-Computer Interaction
By following a couple of simple rules, you can show a clear pattern of cause and
effect, and ensure your viewer is able to make the connection between separate things
happening at the same time.
Research suggests that just as the visual system works to recover the physical
structure of the world by inferring properties such as 3-D shape, so too does it work to
recover the causal and social structure of the world by inferring properties such as
causality and animacy.
1
Perception is finding structure in sensations. Finding a structure to things lets you
hold them in mind and store them in a memory-efficient way. If the structure corresponds to
reality, it can also be used to provide predictions about the thing you’re representing. So
it’s easier to think of several sections of cable on your desk as all being part of the same
mouse lead, and once you’ve assumed that it’s easy to find the mouse, you just follow the
cable away from the stack.
We’ve already seen that the brain looks for structure in space
[
Grasp the Gestalt
]
and structure in time
[
To Be Noticed, Synchronize in Time
]
to
organize perceptions. These principles apply to the basic perception of physical objects, as
well as helping us understand how we make sense of our body images
[
Mold Your Body Schema
]
and the bodies of other people
[
See a Person in Moving Lights
]
.
But our visual system doesn’t look for just static physical structures — it can
also pick up on causal relationships between things. You don’t see two things happening but
rather one event: you don’t stop to wonder why the plate smashed just at the same moment
that it hit the floor.
This ability to detect causation and animacy
[
Make Things Come Alive
]
is a perceptual phenomenon, different
from our slow deliberate reasoning about what causes what (“Hmm...why does my computer crash
only after I have written at least 2000 words without saving?” is a different kind of
nonperceptual, causal reasoning).
When our visual perception picks up on causes it does so quickly and without any
conscious effort on our part. Like with many visual illusions, it happens without your
consent and without any ability on your part to stop it, even if you wanted to and know that
it is illusion.
Here’s one way of seeing what I mean when I talk about the perception of causation.
Make a pendulum, using whatever you have lying around and find something of similar size
to whatever you use as a weight. It doesn’t really matter what you use; I am using the
cord from my camera with my keys as the weight. You’ll also need another small object; I’m
using a large red bottle lid from a drink bottle.
Hold the pendulum up in front of you and set it swinging left to right. Now take the
other object in your free hand and wave it around at the side of the pendulum. It doesn’t
feel like anything special, does it? Now move the other object (in my case the bottle cap)
in time with the pendulum, trying to keep it a fixed distance, say 5 inches, from the
swinging weight. If you get the timing right, you should get the unmistakable impression
that the object in your free hand is pulling the pendulum weight along and then pushing it
back. This happens even though your body has direct evidence that the two events are
causally unrelated: the pendulum moves itself and your own hand moves the unconnected
object.
Notice that you don’t just see the two things as moving together. You get a feeling,
manufactured by your perceptual system and delivered direct into consciousness, that one
thing causes another.
The rules that govern the perception of causation are those you might expect. Events
that happen in close succession and those that have a consistent relationship appear to be
causally connected. But how close together in time and how consistent do things have to be
to be perceived together?
One way of studying these questions is something called the launching paradigm (
http://web.archive.org/web/20040226172716/http://www.carleton.ca/~warrent/210/michotte/michotte.html
), which was developed by Albert Michotte.
In the first demonstration (
http://cogweb.ucla.edu/Discourse/Narrative/michotte-demo.swf
; animated GIF), a red ball enters at the left of the screen and moves until it
meets another red ball in the center of the screen. The first ball then stops, and the
second ball moves off to the right. What you actually see however is more than that; you
see a ball come along and knock into another one to start it moving, as in a game of
pool.
If there is a pause between the two events, as in the second Michotte demonstration (
http://research.yale.edu/perception/causality/temporalGap.mov
), you don’t get the same impression of causality. How big does the pause have
to be? Research has shown that if the pause is longer than 140 milliseconds, the feeling
of one event causing the other is removed.
2
I think this figure of 140 milliseconds might explain why, at a certain delay, using
a gadget becomes annoying. If you press a key on your keyboard but the letter doesn’t
appear until a quarter of a second later, it removes the feeling that what you are doing
with the computer is happening at the same time on the screen. The device stops being
invisible in use and that stops you using it without thinking. It’s annoying, in other
words. I stop being able to type and have to start pressing the keys individually and
waiting for the letters to appear on the screen before I press another one.
— T.S.
Spatial separation can also affect the perception of causality, although this isn’t as
critical as timing, as the pendulum test shows. A gap between the two balls in the
launching paradigm removes causality, but this is a one-off causal relationship rather
than a continuous one as simulated in the pendulum example. You can restore the feeling of
causation by adding another ball between the two separated balls, so that you get a chain
reaction from the first ball to launch the final one. Although the first and last balls
are doing exactly the same thing as in the simple spatial separation example, making
visible a causal relationship between restores the feeling of causality. Brian Scholl’s
movie at the Yale Perception and Cognition Laboratory
3
illustrates this (
http://research.yale.edu/perception/causality/toolEffect.mov
; QuickTime).
Scholl has also shown that visual events that don’t normally create feelings of causal
connection can be changed by the addition of other, related, simultaneous
events that do create a perception of causality. This shows again that timing
is the most important factor our visual system uses for inferring causality.
(Incidentally, the reverse relationship also appears to be true. Events that we code as
being causally related we perceive as being closer together in time than we would otherwise.
4
)
So whether we perceive two events as causally connected is affected by what else is
going on. When you hit a nail with a hammer, you feel as though you’re the cause of the
nail going in, even though your intention (the cause) and the strike (the effect) are
separated in both time and space. The hammer, as a tool that provides a visual connection
between the start and end events, ensures that a feeling of causality is present — one that
wouldn’t be if we saw the cause and effect events without it there.
Experiments have shown that delays of more than 2 seconds can prevent people learning
that one event causes another
5
— although subsequent work has shown that something as simple as giving
people a reason for the delay can double the maximum length of the cause-effect gap that
can be coped with.
6
The important message is that the brain doesn’t really believe in coincidence, so if
you can show what looks like it should be a causal effect, the brain will manufacture up a
feeling of causation to go along with it. You can overcome a lack of direct contact
between events by changing context, but you must get the timing right.
How do we experience our actions as self-caused? It’s not automatic; in fact, the
feeling of consciousness may indeed have been added to our perception of our actions
after
our brains had already made the decision to act.
Place your hand on the table. Look at it as an object, not unlike just about anything
else on the table. Now, raise one of your fingers. Why did you raise that one? Can you say?
Was it a free choice? Or was the decision made somewhere else, somewhere in your brain you
don’t have access to? You experienced your finger being raised by
you
,
but what was it in you that caused it?
If you record EEG readings
[
Electroencephalogram: Getting the Big Picture with EEGs
]
from the scalps of
people just about to decide to raise their fingers and at the same time make them watch a
timer and remember at what time they experienced deciding to raise their finger, they’re
found to report that the experience of deciding to raise their finger comes around 400 ms
after
the EEG shows that their brain began to prepare to raise their finger.
1
Stimulating particular parts of the brain using transcranial magnetic
stimulation
[
Transcranial Magnetic Stimulation: Turn On and Off Bits of the Brain
]
, you can influence
which finger people choose to move,
2
yet they still experience their choice as somehow willed by them, somehow
“theirs.”
This is an example of how an action we feel we own may be influenced by things outside
of our conscious deliberation. The feeling of conscious will isn’t always a good indication
that we consciously willed something. And the reverse can also be true. We can disown
actions we are responsible for, doing things we don’t feel are caused by our own
will.
Draw a cross on a piece of paper. Next, make a pendulum out of something light: a
button and a length of string is ideal. Now hold the pendulum over the cross and ask a
question (“Is the button on this pendulum blue?” or “Is it lunchtime yet?” perhaps). Know
that to indicate “yes” the pendulum will swing clockwise, and to answer “no” the pendulum
will swing counterclockwise. Don’t rest your arm or elbow on anything as it holds the
pendulum. Just watch the pendulum as it begins to swing to answer to your question.
Odds are, the pendulum swung in the way that answered the question
correctly.
What you’ve just experienced is called the
ideomotor
effect.
3
It is the ideomotor effect that lies behind Ouija boards, dowsing wands,
and facilitated communication (when helpers supposedly channel messages from the severely
physically handicapped). There are no demons involved, except for the ordinary everyday
human ones.
The movements produced in these cases are entirely self-caused (and, in the case of
the Ouija board, self-caused
and shared
by a group of people) — but
because we don’t feel we’ve consciously caused the movement, we’re able to disown the
action and it appears to have an external cause, as if it has nothing to do with us.
Spooky! We do (in case you were still worried) have everything to do with it. Muscle
readings from people playing with Ouija boards show that self-generated signals move the
marker; the marker does not move the people’s hands attached to it. Ouija boards only
provide answers that the participants already know — even if that knowledge is false. Some
people have had conversations with “dead” people who have turned out to still be alive.
Blindfolded participants for whom the board is rotated without their knowledge move the
marker to the old, unrotated positions.
So when do we experience an action as self-caused? When don’t we? Daniel Wegner of
Harvard University
4
has suggested that “we experience conscious will when we interpret our own
thought as the cause of the action.” In other words, we infer our feeling of conscious
will when we notice that our intention to act went hand in hand with whatever happened.
That means that if we had no such intention, the feeling of conscious will doesn’t occur
and, conversely, that we can feel an event was self-caused even if it had nothing to do
with us. It’s similar to the feeling of causation
[
Make Events Understandable as Cause and Effect
]
, which we deduce from
our perception of events — we have to, because it’s impossible to perceive cause and effect
directly. Our senses are all we have to work with.
Wegner suggests that the brain uses three basic principles in deciding whether to
deliver an experience of conscious will: priority, consistency, and exclusivity. These
are, respectively: that the thought precedes the action at an appropriate interval, that
the thought is consistent with the action, and that the thought is the only candidate
cause.
Now, in most situations, these conditions are met and we feel as if we properly own
our actions. But in some situations, this isn’t the case and we disown the action, like
those of the pendulum. We make small muscle movements with the hand holding the pendulum,
when thinking of the “yes” or “no”
answer we expect to receive — muscle movements so small that we’re barely aware
that we’re making them. Perhaps we would be aware of our muscles moving, except that the
ultimate effect is so disproportionate: our hands move invisibly, but the pendulum swings
obviously. The microthought versus the large swinging response violates the principle of
consistency, and we can hardly believe that our own actions are a salient cause. That’s
why we don’t experience self-cause and are willing to speculate about other, more
proportionate, candidate causes: spirits from the afterlife and the like.
Given this, it’s easy to see how behaviors that happen without much conscious will
or any effort manage to escape being labeled as self-caused, such as our “monkey see,
monkey do”
[
Monkey See, Monkey Do
]
response to other people’s habits.
The fact that Wegner’s principles are used to understand events external to the brain
isn’t too surprising. After all, we have no direct way of perceiving causation in external
events other than by principles like priority, consistency, and exclusivity. What is even
more interesting is that the brain uses the same principles for understanding internal
events like conscious action. This suggests that there are serious limits to our conscious
insight into the workings of our own brains. There are good computational reasons why this
should be so. You’d be distracted if you were constantly being informed of just how all
your decisions were being made by your brain. Most of the processing
has
to be below the surface for you to operate efficiently. The
ideomotor effect and related phenomenon are evidence that when it came to conscious
understanding of our own actions, our brain found it more convenient to evolve a secondary
set of mechanisms to infer mental causation than open up our mental modules to give us
direct, but time-consuming, insight.