Enjoy this strange new audiovisual illusion from Caltech scientists

Caltech researchers developed the illusion above to illustrate postdiction, a sensory phenomenon "in which a stimulus that occurs later can retroactively affect our perceptions of an earlier event." From Caltech Matters:

"Illusions are a really interesting window into the brain," says first author Noelle Stiles (PhD '15), a visitor in biology and biological engineering and a postdoctoral scholar–research associate at USC. "By investigating illusions, we can study the brain's decision-making process. For example, how does the brain determine reality with information from multiple senses that is at times noisy and conflicting? The brain uses assumptions about the environment to solve this problem. When these assumptions happen to be wrong, illusions can occur as the brain tries to make the best sense of a confusing situation. We can use these illusions to unveil the underlying inferences that the brain makes...."

Postdictive processing has been demonstrated within individual senses, but this work focuses on how the phenomenon can bridge multiple senses. The key to both of the new illusions is that the audio and visual stimuli occur rapidly, in under 200 milliseconds (one-fifth of a second). The brain, trying to make sense of this barrage of information, synthesizes the stimuli from both senses to determine the experience, using postdiction to do so.

Read more in the researchers' scientific paper: "What you saw is what you will hear: Two new illusions with audiovisual postdictive effects" (PLoS ONE) Read the rest

TastyFloats levitates food morsels to your mouth

TastyFloats is a "contactless food delivery system" that uses ultrasound to raise bits of food and droplets of drink to your mouth without any utensils at all. While this method to levitate small objects is well known, what's fascinating is that a small scientific study shows that the levitated food apparently tastes better. Researchers from the University of Sussex describe TastyFloats and their sensory experiment in a scientific paper they'll present at this month's ACM Interactive Surfaces and Spaces conference. From IEEE Spectrum:

The researchers experimented with three of the five basic tastes: sweet (a positive taste), bitter (a negative taste), and umami, which is a savory taste that can also enhance other flavors. The researchers asked a group of volunteers to test TastyFloats with the three basic tastes, delivered in three different volumes (5 microliters, 10µL, and 20µL), with tongue delivery via pipette as a non-levitating control. Participants were asked to identify each droplet, and then rated each on intensity, pleasantness, and satisfaction.

The most significant difference between levitated tastes and tastes delivered via pipette was in intensity: sweet tastes were more intense and recognizable, while bitter tastes were harder to distinguish. The researchers suggest that this might make TastyFloats more suitable for dessert delivery, although it could also be used to make bitter but healthy foods (like broccoli) more palatable to people who wouldn't otherwise enjoy them.

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