Webinar recap: The Science of Persuasive Design

16 Jan 2009 5:00 PM | Anonymous

In the HFI webinar "The Science of Persuasive Design," presenters Kath Straub and Spencer Gerrol highlighted social psychology studies behind persuasive design and many examples of its application. Here's a recap of the talk from TriUPA member Scott Boggs, Web Designer at RTI International.

The webinar was hosted by: Hesketh.com, who also kindly provided drinks and donuts.

“Ugly Options”
A study asked people to choose who they’d like to date from 3 photos: Tom, Jerry, and a photo of Jerry modified to make him less attractive (users did not know this was a modified picture). Most picked Jerry.

Same study, but when photos were: Tom, an “ugly” version of Tom, and Jerryundefinedpeople mostly picked Tom

Take Away: People unconsciously respond to the relation of options presented; the regular Tom or Jerry appeared more appealing when juxtaposed to a similar, but less attractive, choice.

Example: Magazine subscription:

When offered 2 choices:

Web subscription: $58
Print subscription: $125

Most chose the Web subscription.

But when offered 3 choices:

Web subscription: $58
Print and Web subscription: $125
Print subscription: $125

Most chose the Print + Web subscription.

Example: Restaurant Wine sales

People tend to choose the middle option. So with 3 bottles of wine--$8, $27, and $33undefinedmost choose the $27 bottle.
But when higher priced option is added--$8, $27, $33, $51undefinedpeople then tend to choose the $33 bottle.

Take Away: Higher priced option sets an “anchor” of reference. It “reframes” the comparison.

"Social Proof/Social Pressure"
“If others are doing it, it must be good.”

Example: People in shoe store who want to try on what other customers are trying.

Example: Acting troops in urban setting who en masse look at the sky or duck at the same time; regular people all around will also look up or duck.

Example: Towels in Hotel. To encourage customers to re-use towels, hotels first used signs saying “Help Save the Earth”undefinedbut it was not effective (persuasive). Changing it to something like “Other customers are re-using their towels” greatly increased re-use. Further modifying message to something like “previous customers in this room re-used their towels” had an even greater effectundefinedit became even more personal, and thus more persuasive.

Example: Airline website had better purchase ratios when they added a graphic “Top 10 Destination” to certain flights. Even greater success occurred when they added a pop up testimonials from an average customer to the flight listing.

Scarcity has the benefit of Social Proof (others are doing it), plus added pressure.

The same airline website, above, had a further increase in view/purchase ratios when they added the number of seats left to the flight listings. “2 seats left” implies that others are doing it and also creates pressure about availability.

Example: Beef in Argentina
Predictions that bad weather in Argentina would limit beef production led to 2X the usual amount of orders. Announcing that these beef sales would be handled by an exclusive supplier, led to 6X the regular orders.

Example: When shoe salesman person says “I’m not sure if we have that in stock”, customers wanted the items more.

Take Away: the implication of scarcity increasing customers’ anxiety and their likelihood to purchase.

How you present information can make one change their attitude or perception.

Example: 2 presentations of Tooth Flossing scale (desired outcome = call your dentist)

  • How often do you floss each week? 1 2 3 4 5 6 7
  • How often do you floss each month? 1 2 3 4 5 6 7+

Someone who flosses 2x/week ends up on the low end of the 1st scale (framed as weekly), they are more likely to call dentist. But on the 2nd scale (framed as monthly) they are at the topundefinedand thus less likely to call dentist.

Take Away: how you lay out the scale options creates the anchors and thus changes perceptions.


Example: Car wash punch card requiring 8 car washes to get a free oneundefined2 different designs

  • User gets card with 8 empty squares, after getting 8 washes (and the card punched) then they get a free car wash. This had 19% completion rate.
  • User gets card with 10 empty squares, but employee punches 2 to when they give them the card. This had 34% completion rate, almost double the other design.

"Processing Fluency – Rhyme"

Rhyming statements are judged to be more accurate and trustworthy

Example: “Caution and measure will win you treasure.” was perceived as more trusted than “Caution and measure will win you riches.” And likewise for other phrases.

Example: Readsmart typography
Studies showed that in printed text, increasing the white space between clauses, phrases, and sentences and also making phrases end on the same line of text (i.e. not wrap) led to increased ease of reading, better comprehension, and faster reading.

Studies of this type treatment in non-profit donation appeal forms show increased rates of response and also increased amounts of donation.

Take Away: designed the visual display of type to mimic our spoken language makes it more effective. This could help web content to be faster and easier to read. (get your $amp; or <span style=”white-space: nowrap”></span> code ready!)

"Opt In or Opt Out?"

Example: Organ Donation

  • Countries who use an Opt In form, i.e. “Check the box if want to donate your organs” have a low rate of organ donors. (i.e. 20%)
  • Countries who use an Opt Out form, i.e. “Check the box if you do not want to donate your organs” have a much higher rate of organ donors. (i.e. 95+%)
  • In another test, “neutral” yes/no check boxes led to an 80% donation rate, while Opt In had 40% rate, and Opt Out had a 90% rate.

"The Number of Choices Influences Outcomes"

Too many choices leads to increase likelihood of opting out, not buying, not choosing, etc…

Example: Jam sample displays in super market showing 6 jams or 24 jams. The stands with 6 jams had fewer people approach but far more ended up buying the jam. The stands with 24 jams had more people test the jams (bigger display = more noticed?) but significantly fewer people bought any jam.

Example: Kayak.com offers filters in the left column to narrow parameters and reduce listings. People are far more likely to purchase from a list of 4 results than from a list of 500.

Example: When consulting with patients who had tried multiple treatments for hip problems to no avail, doctors who understood the remaining choices to be, 1., ibuprofen, or, 2., Hip replacement surgery were more likely to recommend ibuprofen. However, doctors who understood the remaining choices to be 1. ibuprofen, 2., another medication which demanded some understanding, or ,3., hip replacement surgery were more likely to recommend surgery.

Take Away: too many choices confused customers/users/doctors. They are more likely to act/purchase/etc… when presented fewer choices.

Example of Number of Choices combined with Framing Concept:
People were asked to either:

  • 3 reasons why you love your significant other, or
  • 10 reasons why you love your significant other

And then asked “How much do you love your significant other?” People who were asked to give only 3 reasons felt that they love their sig. other more than people who had to give 10 reasons. Probably, it was harder to give 10 reasons so they perceived that they didn’t love their sig. other as much. It’s similar to the flossing scale above.

"Reciprocity vs. Reward"

Customers develop greater trust for companies/sites who offer them something before they complete some task (i.e. register on the site, give personal information, make a purchase) than for companies/sites who offer them the same thing as a reward after completing the task.

Example: Website had more success in getting users personal information when they offered the related white paper free to any user and then asked for info. They were less successful when they offered the white paper as a reward for giving the personal information. The later strategy resulted in more people giving information (i.e. to get the reward) but half the amount of information was given.

Persuasion techniques can amplify motivations and/or remove blocks and barriers.

For more information, you can visit the presenters’ website: http://humanfactors.com/petdesign/

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