Motion transfer compared
Winner: The all-foam Casper mattress passed our motion transfer tests, while the Hybrid failed each time.
Motion transfer isolation or dampening is an important mattress feature because it will help you get a good night's sleep even when your partner is tossing and turning. The fewer times you wake up, the more productive your sleep will be.
Based on my research, I created a makeshift motion transfer test with the materials I had available. First, I placed a 12-ounce can of soda upright on the center of each mattress. Then, I dropped a 20-pound weight from four feet above the mattress so that it landed 12 inches from the can. If the can stayed upright after several iterations, the mattress has good motion transfer dampening properties. If the can fell over consistently, the mattress has poor motion transfer properties.
In my tests on the Casper all-foam mattress, the can remained upright each time. With the Hybrid, the can always fell over. My subjective experience backed these results up. I shared the Hybrid bed with my wife, and she occasionally woke me up with her sleep troubles — a common problem for her.
Though I did not share the all-foam mattress with my wife, I did have a stream of pets walking on it while I slept. They didn't wake me up. The only evidence I had that they were there were random toys and occasionally they would be asleep next to me when I awoke in the morning.
These results tell me that the Hybrid may be better for individuals who mainly sleep alone or are heavy sleepers. The all-foam Casper mattress does a better job of isolating motion transfer, which is ideal for couples sharing a bed.
I also want to point out that poor motion transfer isolation usually translates to more bounciness. Bounce is nice to have when engaged in intimate activities. Yet, neither mattress exhibited much bounce. This may have been due to the foundation (i.e., our floor) having zero give. The all-foam Casper was nice because it did allow for easier movement on top of the mattress, which is helpful for a variety of reasons.