Thursday, June 2, 2011

A few words on subliminal advertising

Summer movie season is here, and the chances are good that you will spend some time in the theater watching at least one of the blockbusters.  Along the way, you might even stop by the snack counter for some popcorn, candy, or a drink. 

Thinking about the movies and snacks often gets people thinking about subliminal advertising as well.  In the 1950’s, an advertiser suggested they had spliced images of brand names into movies at speeds too fast to be noticed and had influenced people’s purchases.  While this story turned out to be a hoax, many people believe that these kinds of brief presentations can really affect what you buy.

So, what is really going on?

Let’s take this in pieces.  First, it really is possible to present items to people that affect their behavior without awareness.  The word subliminal means “below the threshold,” and refers to items that are presented too fast to be noticed consciously.

If you flash something for one frame of a movie, it is presented for about 1/60th of a second.  Because there is an image shown before and after it, you will notice the image consciously, but it will be processed by your visual system, and some information will get through.

The information that gets into the cognitive system makes it easier to think about the concept that was flashed.  Lots of work has shown that subliminal presentations of words will make you faster to respond to other related words.

So, how will this affect choices?

A nice study in the April, 2011 issue of the Journal of Consumer Psychology by Thijs Verwijmeren, Johan Karremans, Wolfgang Stroebe, and Daniel Wigboldus lays out the main factors.  They were interested in choices for drinks.  They measured participants’ level of thirst.  They also determined how much people typically buy two different brands of drinks (one was an ice tea and the other was a bottled water). 

After making these judgments, people were asked to do a simple task in which they saw a row of capital Bs (BBBBBBBB), but on some trials there was also a lower-case b in the row (BBBbBBBB).  They had to count the number of trials where there was a lower-case b.  Before each of the rows of Bs were presented, half the participants saw the brand name of the ice tea flashed on the screen subliminally.

At the end of the study, participants were allowed to select either the ice tea or the water to drink.

The pattern of data is a bit complicated, though it ultimately makes a lot of sense.

When you are not thirsty, the subliminal message has very little effect on your choices.  You tend to pick the drink you generally like.

If you are thirsty, and you have a strong preference for the brand that was shown subliminally, it has no real effect on your choices.

If you are thirsty and you have no real preference for either drink, then you tend to pick the brand that was shown subliminally.

If you are thirsty and your less-preferred drink was shown subliminally, you tend to pick the brand that was shown subliminally (which goes against your habit).

Putting all this together, then, subliminal advertising can have some effects on your choices, though it will not turn you into a robot.  First, subliminal ads only have an effect if you are already motivated to pursue a goal.  So, the subliminal ad will not make you do something you don’t want to do.  Second, subliminal ads have their strongest effect when they make it easier for you to think about something that is not normally your habit.  That is, the subliminal ads tend to favor the underdog.

So go to the movies <follow me on Twitter>, and don’t worry <follow me on Twitter> about ads affecting your trips to the snack bar.

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