A misdirection of mind

Scientific American has an excellent video where two neuroscientists and a street magician with remarkable pickpocketing skills explain how illusionists manipulate our attention.

It’s a hugely entertaining piece and really highlights how the idea of ‘sleight of hand’ is itself a misdirection, as the most important of the magician’s manipulations is to alter where we focus and what we expect.

The people featured in the video were all involved in the recent scientific discussions about what stage magic can teach cognitive neuroscience about the mind and brain.

You’ll also notice there is a bit of scientific sleight of hand that happens at about the 9 minute mark where the all-purpose ‘mirror neuron‘ theory is pulled out of a hat as an explanation that stretches way beyond what we actually know about the mirror system.

It doesn’t say whether mirror neurons can also saw a woman in half but I’m sure someone will suggest it in the near future.

Despite this moment of unsubstantiated speculation, the video is an excellent guide to the psychology of attention and great fun to boot.

Link to video ‘Neuroscience meets magic’.

Why are overheard phone conversations so distracting?

Psychological Science has a brilliantly conceived study that explains why overhearing someone talk on a mobile phone is so much more annoying than simply overhearing two people in conversation.

It turns out that a one-sided conversation (brilliantly named a ‘half-a-logue’) draws in more of our mental resources because the information is less predictable – like being fed a series of verbal cliff-hangers.

Overheard Cell-Phone Conversations: When Less Speech Is More Distracting.

Psychol Sci. 2010 Sep 3. [Epub ahead of print]

Emberson LL, Lupyan G, Goldstein MH, Spivey MJ.

Why are people more irritated by nearby cell-phone conversations than by conversations between two people who are physically present? Overhearing someone on a cell phone means hearing only half of a conversation-a “halfalogue.” We show that merely overhearing a halfalogue results in decreased performance on cognitive tasks designed to reflect the attentional demands of daily activities. By contrast, overhearing both sides of a cell-phone conversation or a monologue does not result in decreased performance. This may be because the content of a halfalogue is less predictable than both sides of a conversation. In a second experiment, we controlled for differences in acoustic factors between these types of overheard speech, establishing that it is the unpredictable informational content of halfalogues that results in distraction. Thus, we provide a cognitive explanation for why overheard cell-phone conversations are especially irritating: Less-predictable speech results in more distraction for a listener engaged in other tasks.


Link to PubMed entry for study.

Distractingly attractive

Driver distractions are a major cause of road accidents. A new study has found that just a simple conversation with someone else in the car can be enough to increase driver errors and that the risk is greater if we fancy the passenger.

The research was conducted in a driving simulator by Cale Whitea and Jeff Caird from the Cognitive Ergonomics Research Laboratory (CERL) at the University of Calgary in Canada where they investigated something called a looked-but-failed-to-see error.

This is a form of change blindness, where we look at a scene but fail to notice something has changed. This is an important source of risk when driving, as we may be going through the motions of scanning the road but not taking in new information.

The study looked at how many of these errors would occur when drivers navigated their way through a simulated city, while also tracking their eye movements and errors with motorbikes and pedestrians on dangerous left-turns.

Crucially, the study compared how people performed when they were alone or with an opposite-sex passenger but also asked them about how attracted they were to the passenger and tested levels of extroversion and anxiety.

The results were striking:

Passenger conversations can be distracting. Higher rates of [looked-but-failed-to-see] LBFTS errors occurred when engaged in conversations with attractive passengers. In particular, those drivers who were most extroverted and attracted to the passenger also tended to be more anxious, drove slower, responded less to the pedestrian, and were involved in a greater number of emergency incidents with the motorcycle.

Considering eye gaze behavior was unaffected, the relationship between these social factors and performance variables suggest the nature of conversational distraction is cognitive. This attentional interference was sufficient in eliciting an eight-fold increase in LBFTS errors involving the motorcycle and four-times more pedestrian incidents.

In other words, conversation did not alter how people looked at the road, but it did affect how many dangerous situations people noticed – they just didn’t take them in. Fancying the passenger meant drivers missed more hazards. Their mind was clearly on other things.

Contrary to what parents might say (‘you were just showing off!’) participants actually drove more slowly when they were attracted to the passenger, but still made more errors.

It’s probably worth noting that it wasn’t the hotness of the passenger which was tested in the experiment, but the attraction of the driver, and that the distracting effect was stronger in women than men.

Link to PubMed entry for study.

Do the test: change blindness versions

dothetest.co.uk, is the Transport for London site which brought you the urbanised inattentional blindness video. Now they’re back with a feast of change blindness-YouTube goodness, here, here, and here.

The moral is the same, and evidence-based: even large things can be hard to spot if you don’t know they are there, so look out for cyclists.


Transport for London have combined two of my favourite things: safety for cyclists and classic Psychology experiments. The website dothetest.co.uk provides a test of awareness that Mind Hacks fans will instantly recognise as an updated (urbanised!) version of Hack #41: “Make Things Invisible Simply by Concentrating (on Something Else)”. Fantastic!

Link to the awareness test here

Link to a previous post on mindhacks.com discussing inattentional blindness

Resisting temptation is energy intensive

Cognitive Daily has just published a great write-up and demonstration of a study that illustrates how self-control is an energy intensive process that puts a big drain on the body’s glucose levels.

The article tackles a recent study [pdf] led by psychologist Matthew Gailliot that found that exercising self-control in either conversations or in lab tasks reduces blood glucose levels.

The researchers also found that initial glucose levels can predict how well people do on these tasks and that self-control can be temporarily boosted by giving people a sugary drink.

Cognitive Daily’s have recreated one of the lab tasks. Go and check it out, it’s an excellent demonstration. It makes the task wonderfully clear but also illustrates how even such simple self-control tasks are so difficult.

This sort of ‘self-control’ is heavily linked to attention – in part, the ability to focus yourself on one particular thing and not get drawn into perceptual or emotional distractions.

This study doesn’t tackle brain function, but another recent paper by Gailliot [pdf] does link these findings to what we know about the neuropsychology of ‘self-control’.

This ability is particularly associated with the frontal lobes, which are known to play a key role in inhibiting inappropriate responses.

You can see control break down in interesting ways after frontal lobe damage, which can often lead to a range of impulsive behaviours.

For example, patients with damage to this area might display utilisation behaviour, where they are unable to resist carrying out actions presented by their environment.

The affected person might be unable to walk past a door without trying to open it or sit in front of a coffee cup without sipping it, even when they know it’s too hot to drink.

What’s interesting, is that as the CogDaily article illustrates, we seem to have a mild form of this when we are low on energy or fatigued.

It’s interesting to speculate that the reason we get ‘snappy’ when tired is because we’re less able to control the emotions sparked by small annoyances.

Link to great CogDaily article on self control (try the demo!).

Are attention and consciousness the same thing?

Psychologists have often wondered whether attention and consciousness are the same thing. Can we only be conscious of things we pay attention to? And can we attend to things we’re not conscious of?

A paper [pdf] published last year suggests that they are, in fact, separate mental processes.

William James, one of the founder of modern psychology, wrote that “everyone knows what attention is” when trying to define it.

Similarly, as neuroscientist Susan Greenfield has pointed out, scientists often rely on a ‘we all know what we’re talking about, don’t we?’ definition of consciousness.

It turns out that attention is easier to define that consciousness, and in psychology it generally refers to the preferential processing of one source of information over another.

This can be measured experimentally because it’s possible to see how experience of one thing affects performance on another task, even if the person isn’t aware of experiencing anything in the first place.

We described an example of this last week, in a study that found that people could make accurate beauty judgements for faces presented so quickly they didn’t consciously recognise them.

This study, and many others on ‘implicit’ or ‘subliminal’ perception, demonstrate that people can attend to something without being conscious of it.

Being conscious of something we haven’t attended to, and where attention is nearly absent, is a bit more tricky.

The paper, by cognitive scientists Christof Koch and Naotsugu Tsuchiya, suggests that getting ‘gist’ impressions might be one example.

Experiments show that when photographs are unexpectedly flashed up in front of participants for no more than 30ms, they don’t have time to focus on any part of it, but can report a general gist or summary of the image.

Consciousness and attention have also been shown to have opposite effects in some instances.

When participants try to find two embedded images within a rapidly flashed stream of pictures, they often fail to see the second image – an effect known as ‘attentional blink‘.

However, one study [pdf] found that distracting people during this task, actually made them better at it, they were more likely to consciously detect the second image.

Reducing their attention to the task seemed to increase their conscious awareness.

The Koch and Tsuchiya paper has many more examples if you’re interested in trying to untangle these closely related processes.

pdf of ‘Attention and Consciousness: Two Distinct Brain Processes’ (via SciCon).