Experiences that engage multiple senses create stronger memories and higher engagement. In digital interfaces, this means sound design, haptic feedback, micro-animations, and visual richness — creating a multi-channel experience that transcends pure visual interaction.
The study of multi-sensory integration — how the brain combines inputs from different senses — was formalised by Barry Stein and M. Alex Meredith in their 1993 book The Merging of the Senses. Their research showed that neurons in the superior colliculus, a region of the brain involved in orienting behaviour, respond far more strongly to stimuli that combine multiple sensory modalities than to unimodal stimuli. A sound and a light appearing simultaneously produce a response in certain neurons that is ten times stronger than either alone. The brain is built to integrate senses, and it actively values the richness that multi-sensory stimulation provides.
Digital interfaces are inherently impoverished in sensory terms: flat, silent, and untouchable by default. Every pixel on every screen is communicating only through one sense — vision. But within the visual channel, designers have significant range: motion, texture, depth, colour, shadow, and the simulation of physical properties can all be deployed to create sensory richness that makes a flat interface feel more responsive, more physical, and more real. On mobile devices that range extends to haptic feedback — the vibration patterns that accompany touch interactions — and to sound, which the best-designed systems use sparingly and specifically.
The cognitive consequences of sensory richness are well-documented. Harrison, Amento, Kuznetsov, and Bell's 2007 research on progress bar animations found that smoothly animated progress indicators were perceived as completing 11% faster than equivalent static bars — the same duration, the same information, but the sensory richness of the animation changed the subjective experience of time. Ngo, Teo, and Byrne's work on sound quality in interfaces found that the aesthetic quality of UI sounds predicted users' overall perception of the interface's quality even when they could not articulate what made it good. The senses are not delivering information about the interface. They are delivering information about whether the interface is worth trusting.
“Multi-sensory stimulation produces neural responses far stronger than any single sense alone. The brain rewards richness.”
— Barry Stein & M. Alex Meredith, The Merging of the Senses, 1993
A like button that changes from grey to red is delivering information: the state has changed. A like button that expands, bounces, emits particles, and then settles into its new state is delivering the same information through a sensory event — one that the brain processes as a physical interaction rather than a data update. The difference in felt experience is the difference between being told something happened and feeling it happen.
Instagram's research on their like animation found that users who interacted with the animated version reported feeling more satisfied with the action, were more likely to continue scrolling, and rated the product as “more alive” in unprompted descriptions. The animation did not add functionality. It added the sensory feedback that makes the action feel real.
The two hearts deliver identical information. The difference is entirely in the sensory channel — the right one simulates the physical properties of a real button: expansion on press, spring-back on release, a burst of energy at the moment of commitment. These animations map onto the sensory expectations the brain has for physical objects. When a digital interaction satisfies those expectations — even through purely visual means — it feels more real. When it does not, the interaction registers as a data update rather than as an event the user participated in.
The moment of task completion is the emotional peak of any interaction flow. Kahneman's peak-end rule establishes that this peak is disproportionately weighted in the user's memory and overall evaluation of the experience. A success state that provides no sensory richness — a text label that changes from “Submit” to “Submitted” — produces a flat peak. A success state that delivers a sensory event — a drawn checkmark, an expanding ring, a colour sweep — produces a felt peak that the user remembers and that colours their evaluation of the entire preceding interaction.
Both flows below submit to the same endpoint. What differs is what the user is left with at the moment of completion.
The sensory version adds nothing functional — the data is identical. What it adds is a felt moment of completion: the eye follows the checkmark as it draws across the circle, the expanding rings pulse outward, the text fades in with a delay that gives each element its own moment. The brain processes this as a real event rather than as a state change. And because it is the emotional peak of the interaction, it is weighted disproportionately in the user's memory of the experience.
Waiting is inherently uncomfortable. But the experience of waiting is not determined solely by its duration — it is shaped by the sensory environment the user is in while waiting. Harrison and colleagues' 2007 research demonstrated that animated progress indicators are perceived as completing 11% faster than static ones for the same actual duration. The animation gives the brain something to track, creates a sense of active progress rather than suspended time, and transforms waiting from a passive experience into an observable process.
Both progress indicators below run for the same eight seconds.
The animated progress bar does not finish faster. It does not deliver more information. What it delivers is sensory engagement during the wait — the shimmer gives the eye something to track, the eased progress feels like natural physical movement, the step labels give the mind something to process. The brain, occupied with tracking these sensory signals, allocates less attention to the experience of waiting itself. Harrison et al.'s 11% perceived speed improvement emerges from this reallocation of attention, not from any change in actual duration.
Sensory richness is a tool for specific moments, not a blanket applied to every interaction. The goal is to deploy sensory feedback where it adds felt value — core actions, completions, waits, transitions — while respecting the user's attention, accessibility preferences, and the reality that what delights on first use becomes friction on the hundredth.
Stein, B. E., & Meredith, M. A. (1993). The Merging of the Senses. MIT Press. · Harrison, C., Amento, B., Kuznetsov, S., & Bell, R. (2007). Rethinking the progress bar. ACM UIST Proceedings. · Ngo, L., Teo, J. C., & Byrne, J. G. (2001). Modelling interface aesthetics. Information Sciences, 152, 25–46. · Schifferstein, H. N. J., & Cleiren, M. (2005). Capturing product experiences. Acta Psychologica, 118(3), 293–318.