Psychology Archive

Change Blindness, Saccadic Masking: Eye Hacks – Oh My!

By Dan Zambonini, June 30, 2010, 5:39 pm in Physiology, Present, Psychology

In the above video, 75% of the people tested failed to notice that the person they were talking to was swapped with a different person during their conversation. In a similar experiment conducted by Derren Brown, about 50% of people failed to notice that a person asking them for directions was swapped-out during their interaction. This phenomenon is referred to as Change Blindess or Inattentional Blindness – our inability to detect large changes in a scene.

We also experience some form of ‘blindness’ on a very small scale. Our brain performs something called Saccadic Masking during certain types of fast eye movements (saccades), where our vision is massively impaired during the movement, but our brain uses before and after snapshots to hide the fact that we were unable to clearly see during the movement – in effect, it is hiding the useless blurred image of movement from us.

You can see this in action with a simple experiment. Grab a friend and a mirror. Look into the mirror, and stare at one eye, then switch to the other, then back again. You won’t be able to see your eye movement (your brain is masking it), but your friend will.

For more information, check out Hack #17, Glimpse the Gaps in Your Vision (pdf) from O’Reilly’s excellent Mind Hacks book.

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Numbers Stations – The Soundtrack to Your Nightmares

By Dan Zambonini, June 24, 2010, 8:32 am in History, Music, Past, Psychology

Lego spy figure

Listen to a minute of this, from about 0:50 onwards: The Swedish Rhapsody (MP3).

This spooky sound is sampled from a Numbers Station. Hundreds of these shortwave radio stations exist around the world, transmitting numbers, letters, beeps and simple tunes. Their origin – and ongoing transmissions – still largely remain a mystery.

Are they secret codes and directives for spies in foreign countries? Are they sources of misinformation to distract the enemy? Perhaps messages between druglords? Hoaxes by amateur enthusiasts? The answer is probably: yes, all of these, and more besides.

The Conet Project sampled 150 transmissions from 20 years and released them on a 4CD set (“Not available in stores!“, I suspect). This is currently “out of stock”, but the recordings are also available on archive.org, should you wish to disturb yourself some more.

You can read more about Numbers Stations on Damn Interesting, and Boing Boing’s coverage of the copyright fight between The Conet Project and Wilco, who used a sample of the recordings on their Yankee Hotel Foxtrot album. Wikipedia also has entries for some individual stations, including The Lincolnshire Poacher, Cherry Ripe, and UVB-76.

Lego spy photo under Creative Commons license from Flickr user Dunechaser.

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Do Full Moons Cause People to Become More Violent?

By Amy Thibodeau, June 1, 2010, 11:15 pm in Past, Psychology

The werewolf myth is one that has become iconic in popular culture. There are dozens (at least) of films about the full moon turning human beings into monsters from An American Werewolf in Paris to the classic from the 1950s, The Curse of the Werewolf. The legend of the werewolf can be traced back deep into literature and myth from around the world. In The Metamorphoses, Ovid writes of King Lycaon who is changed into a werewolf by the gods after eating tainted meat.

Although there is some evidence to suggest that full moons might cause changes in human behaviour, it is mostly anecdotal and too sporadic to be considered factual. For example, in 1978 a study called Human Aggression and the Lunar Synodic Cycle found that in “11,613 cases of aggravated assault in a 5-year period: assaults occurred more often around the full moon.” (source)

More recently, in 2007, Sussex police announced that they found a correlation between the incidence of violence among drinkers in the seaside town of Brighton.

“I compared a graph of full moons and a graph of last year’s violent crimes and there is a trend,” Inspector Andy Parr told the Brighton Argus newspaper. “People tend to be more aggressive generally. I would be interested in approaching the universities and seeing if any of their post-graduates would be interested in looking into it further. This could be helpful to us.” (source)

It should be noted that “in separate findings,  [the Brighton] police also found that violence in pubs and nightclubs increased on paydays.”

Image: Full Crow Moon by Dave

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Using Starbucks Stores to Model Retail Gravitation

By Dan Zambonini, May 18, 2010, 8:01 pm in Business, Culture, Present, Psychology

Retail Gravitation Breakpoint for Manchester and London

You live the same distance away from two cities and decide to go shopping – which do you go to; the one with the most stores, right? What if you didn’t live the same distance away from each city – how far would you have to be away from the larger one, in order to decide that it’s easier just to go to the smaller, closer one?

That question is the crux of William J. Reilly’s 1931 Law of Retail Gravitation. He asserted that:

the Break Point (BP) [from city p2] is equal to the Distance (d) between two places, divided by the following: 1 plus the Square Root of, the size of Place One (p1) divided by the size of Place Two (p2). (slightly paraphrased from the previous Wikipedia link)

The “size” of a place is a little arbitrary, but you could use figures such as the total square-footage of retail space, or the total number of unique stores. Either way, this data is fairly difficult to track down.

Luckily, ubiquitous stores like Starbucks are a good indicator of the larger retail environment, so we can use their UK Store Locator to count the total number of Starbucks stores in each city, and use this as a good estimate for ‘Retail Size’.

Retail Break Points for UK Cities, compared with London

Obviously the Break Point figure, in miles, will be larger for the cities that are further away from London, such as the Scottish cities. Therefore a more interesting statistic is the Break Point distance in terms of percentage of the total distance (the green line in the graph above). This demonstrates the relative ‘pull’ of each city, influenced by the number of Starbucks (which, remember, we’re using to represent the total number of stores). Looking at these figures, we can see how the lack of Starbucks in Liverpool is causing a relatively low ‘retail pull’ towards the city, whereas the additional Starbucks stores in Manchester give it almost the same relative ‘pull’ as the much farther away Edinburgh.

Just because I had the data, here’s a bonus graph of People per Starbucks for each city:

People per Starbucks Store, for UK Cities

Looks like Liverpool and Birmingham need a few more stores.

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Good Wine – A Matter of Taste or Perception?

By Amy Thibodeau, February 23, 2010, 8:48 pm in Past, Psychology

Last week a group of twelve wine executives from France were found guilty of fraud when they substituted the more expensive grapes typically found in Pinot Noir for a cheaper variety. Their label – Red Bicyclette – is a fairly popular brand in North America and the worry is that following this conviction, their deception will be detrimental to the wine industry, particular in the Languedoc region of France where the company is based.

The thing I find interesting about this case, and wine in general, is that the consumers of Red Bicyclette didn’t seem to notice the difference between the expensive grapes and the cheaper ones. There were no notable customer complaints and no one is saying that the wine didn’t taste pretty much the same as it would have if they’d done things properly. The fraud was uncovered during an audit when it was found that the company could not have been turning over as much profit if they were also spending money on the expensive grapes.

Even though consumers couldn’t tell the difference (or at least, if they did it wasn’t significant enough to report), there is almost no doubt that there will be a retaliation against the wine industry from Languedoc. Research suggests that a good deal of our decisions about which wine to drink is actually based on abstract psychological reactions and cultural context rather than on a genuine ability to discern superior grapes by taste. Two examples:

  • After the film Sideways was released, Merlot sales in the US dropped by 2%, while Pinot Noir sales increased by 16%, presumably as a response to the character Miles’ appreciation of one and denigration of the other. (via Wikipedia)
  • “Restaurant owners will often price the wine they buy cheapest at wholesale as the second-cheapest wine on the menu. Why? Because people generally don’t order the cheapest wine and thus often turn to the second cheapest.” Presto – either because consumers don’t want to appear cheap or because we imagine the cheapest option will have the worst taste, we predictably buy the second-cheapest. (via Lone Gunman)

How many of you can really tell the difference between a good wine and a mediocre one?

Rocket Bar Wine image by Mr. T. in DC

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