The absence of numbers to express the amount may affect delay discounting with humans
Taking numbers off the screen wiped out the usual \'small rewards fade faster\' pattern in delay discounting.
01Research in Context
What this study did
The team asked 40 college students to pick between small money now or bigger money later.
Half the choices showed the amounts as numbers (\$5 vs \$40). The other half showed the same amounts as dots (••••• vs •••••••••••••••••••••••••••••••••••••••••••••••••••).
Each student made 120 picks on a computer. The screen never showed the word dollars or any digits in the dot condition.
What they found
With numbers, people acted like the textbooks say: they discounted the small amount faster than the big amount.
With dots, that pattern vanished. Students treated \$5 and \$40 almost the same when they saw dots.
In plain words, no numbers = no magnitude effect.
How this fits with other research
Ainslie et al. (2003) showed rats can wait longer when rewards come in a bundled series. Both studies prove that how you show the payoff changes patience, even though one used rats and the other humans.
Austin et al. (2015) found that tokens do more than bridge delays—they act like extra cues. Reyes‐Huerta et al. (2016) adds another layer: the way you state the amount (dots vs digits) is another cue that can override the size itself.
Franck et al. (2023) gives us the math tool (Rachlin’s two-parameter model) that future studies can use to fit these dot-based choices cleanly.
Why it matters
If you run delay-discounting assessments, try showing rewards as pictures, tokens, or dots instead of digits. You may remove the built-in bias people have against small amounts. This could help clients who over-value immediate rewards see the bigger pile as worth the wait. One quick swap—numbers to dots—may level the field.
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02At a glance
03Original abstract
Human delay discounting is usually studied with experimental protocols that use symbols to express delay and amount. In order to further understand discounting, we evaluated whether the absence of numbers to represent reward amounts affects discount rate in general, and whether the magnitude effect is generalized to nonsymbolic situations in particular. In Experiment 1, human participants were exposed to a delay-discounting task in which rewards were presented using dots to represent monetary rewards (nonsymbolic); under this condition the magnitude effect did not occur. Nevertheless, the magnitude effect was observed when equivalent reward amounts were presented using numbers (symbolic). Moreover, in estimation tasks, magnitude increments produced underestimation of large amounts. In Experiment 2, participants were exposed only to the nonsymbolic discounting task and were required to estimate reward amounts in each trial. Consistent with Experiment 1, the absence of numbers representing reward amounts produced similar discount rates of small and large rewards. These results suggest that value of nonsymbolic rewards is a nonlinear function of amount and that value attribution depends on perceived difference between the immediate and the delayed nonsymbolic rewards.
Journal of the Experimental Analysis of Behavior, 2016 · doi:10.1002/jeab.218