People more likely to defer making decisions the longer they wait

Would you rather eat an apple or a banana? Read Moby Dick or A Tale of Two Cities? Is a cup or a mug holding that coffee?

How quickly the decision gets made matters. That's because the longer someone takes to draw a conclusion, the more likely that person will disengage from the process altogether and simply never decide.

This phenomenon is called choice deferral, and it's the topic of a new paper published in Cognitive Psychology from University of Pennsylvania psychologist Sudeep Bhatia in collaboration with Timothy Mullett of the University of Warwick. They found that, on average, if more than 3.5 seconds passes without a decision happening, none will likely occur for the choice at hand.

"You can imagine that, if you're going to buy a car, you're going to spend more than three and a half seconds," said Bhatia, an associate professor in Penn's School of Arts & Sciences. "This parameter would vary based on the importance of the choice or even based on the setting. A person who only had a single choice would probably spend a little more time on it."

Bhatia and Mullett specified their theory by using a sequential sampling model Bhatia had published several years ago. It's essentially a computer-facilitated mathematical model. For this experiment, they asked study participants to select Movie A or Movie B as many as 200 times in rapid succession. Test 1 might pair two action flicks, one of lesser quality. Test 2 would then put together an action film and a documentary. Sometimes, a third option appeared: the person could defer the decision altogether and wait for a more preferable film.

The researchers then analyzed the results, looking at factors like how much evidence someone needed to make a decision and whether a choice changed with the added deferral option. Though this phenomenon is well known, particularly in marketing, the researchers learned that, from a cognitive perspective, it's complicated.

"Decisions are more likely to be deferred when the choice has conflicting alternatives or large trade-offs," Bhatia said. The same goes for equally preferable options, he added. "In a setting where one option is much better than the other, people are less likely to defer, likewise in the setting in which two options don't really involve trade-offs."

As an example, Bhatia described a vacation scenario in which Option A is a seven-day Alaskan cruise, Option B is a seven-day Caribbean cruise and Option C is a six-day Caribbean cruise. They all cost the same. Without the six-day Caribbean option, the decider is most likely indifferent about both cruises; throw in the shorter tropical one, however, and its longer counterpart gets picked the majority of the time.

"There is a pretty standard understanding of what it means to defer a decision, to disengage from that choice. But there is a lot of debate about what causes this," Bhatia said. "How do you explain these findings? They fall out of a simple model that assumes that, if a choice isn't made by a certain time, it ends up being deferred."