Case Study - Baby App
April 28, 2025
In the swirling chaos of new parenthood, cognitive load and tiny frustrations can quickly snowball. We are building a Baby App that tackles this head-on with a design philosophy rooted in behavioural psychology and expressed through meticulous micro-interactions, all with one goal: to make every interaction as effortless as possible.
In our design process we rely heavily on behavioural psychology to craft User Experiences that are simply outstanding. In the following paragraphs we want to show you a small selection of the concepts that guide our design decisions.
Cognitive Load
In the swirling chaos of new parenthood, cognitive load and tiny frustrations can quickly snowball. We are building a Baby App that tackles this head-on with a design philosophy rooted in behavioural psychology and expressed through meticulous micro-interactions, all with one goal: to make every interaction as effortless as possible.
Guided by the belief that no amount of development time is too great if it spares users even a moment of hassle, the app transforms the daunting chore of setting up parental allowance into something surprisingly manageable.
Even the app bar itself adapts to the current reality: knowing you might have only one hand free, a dynamic navigation bar keeps every control comfortably within a thumb’s reach.
The control center
Anchored like a trusty sidekick at the bottom edge of every screen, the Baby App’s adaptive navigation bar morphs to match the moment. On the calendar view, for instance, it becomes a fingertip-ready control center.
Research on one-handed thumb use demonstrates that optimal target sizes for single-tap tasks are around 9.2 mm for discrete actions and 9.6 mm for serial tapping, and that key placement should reside within the natural “accurate region” of the thumb’s reach envelope [5]. Further, studies identify differences in reachability and accuracy across screen locations—favoring bottom-left and center for right-hand use [6].
Let’s first dive into what use cases the calendar has to satisfy. The time window that is of interest to the user is the current week, the coming week as well as a certain time period in the future in case the user wants to go on vacation. The current and next week’s events are shown per default as the user will want to access this information most frequently.
The access of a certain time in the future is a bit more tricky as we have no way of knowing the time period beforehand. That’s why we have to give the user the ability to filter for the desired time period. Usually this type of filter would be placed at the top right next to some display of the current date. This violates our Single Hand Usage Principle. Our Control Center Navigation Bar comes to the rescue. Our Tabs collapse into a single icon and a seconds option is added to the control center: our icon filter. And by tapping on it we smoothly expand the tab bar into a calendar selection card that can then take up the bottom third of the screen. There the user can easily filter for the desired time period and also quickly jump back to the current week.
Progressive disclosure—revealing only the information needed at the moment—aligns with both CLT and usability principles. By collapsing filter options into a single icon that expands into a bottom-third calendar card, we avoid overwhelming the user while still providing advanced filtering when required [1].
Another example is the Detail View of an event in the calendar. The user needs a way to navigate back to the overview. And again the usual position for this functionality would be all the way up at the top of the screen, this time at the top left. For our app we again collapse the navigation bar and add an option to go back to the overview screen.
By keeping essential actions in the natural thumb zone, the nav bar turns one-handed use from a compromise into the default—proving that thoughtful micro-interactions can be as comforting as an extra burp cloth when multitasking in parenthood’s busiest season.
The parental allowance application
To new parents already juggling midnight feedings and nursery paint swatches, the parental-allowance form can feel like a looming paper mountain—its shadow stretching over the crib long before the baby has even arrived.
The dread comes from a pair of intimidating forces: first, the form stretches on over countless pages almost the length of a small novel, and second, every line is woven with dense bureaucratic language that turns simple answers into a maze of legalese.
Cognitive Load Theory (CLT) posits that human working memory is limited, and instructional designs that split complex tasks into smaller, well-sequenced elements reduce extraneous load, freeing capacity for learning or task completion [1, 2, 3]. Moreover, the classic “chunking” principle—grouping individual items into larger, meaningful units—further increases memory efficiency by treating several pieces of information as one coherent unit [2, 3].
Application: Instead of a single, lengthy parental-allowance form, we divide the process into one-question screens, each requiring only a single data point. This approach directly minimizes unnecessary working-memory demands and aligns with both CLT and chunking strategies.
The Baby App picks up a digital scalpel and carves that marathon form into bite-size sprints—quick, one-minute tasks you can knock out while the bottle warms. Behind the scenes it auto-drops in every date, sum, and duplicate detail it can deduce, so your thumb only grazes the fields that truly need you. By the time parents tap the last “submit,” they’re startled to realize they’ve quietly crossed the whole mountain—never once glimpsing how high the summit actually was.
Instead of confronting parents with one overwhelming form, it splits the application into tiny parts spread out over several months further reducing the cognitive load for one individual app session [3]. Large-scale usability studies show that reducing form fields and leveraging auto-completion can boost completion rates by up to 35% by removing repetitive entry and errors [6]. Furthermore, providing automatic address lookup (e.g., street → city/state/ZIP) eliminates common input friction and validation failures [7].
Application: Information is quietly auto-filled whenever possible, and dense legal jargon is translated into plain, friendly language tailored to each user’s situation. Each screen asks just one easy question—a deliberate choice to minimize cognitive load, especially crucial for sleep-deprived expecting couples and new parents. And when life interrupts (as it inevitably does with a baby in the mix), this app picks up right where you left off, referencing your previous answers on the current screen to maintain a seamless sense of flow.
Taming the legal thicket takes more than pruning; it calls for a built-in guide. The Baby App begins by swapping cryptic fields for friendly multiple-choice tiles, quietly collapsing whole sub-forms the moment they become irrelevant, and self-checking entries so errors never stick. Yet its real magic blooms in the little “explain” bubbles that translate every knot of law into plain conversation—and in an auto-fill engine smart enough to weave Basis-Elterngeld, ElterngeldPlus, and Partnerschaftsbonus into one seamless and coherent combination that perfectly fulfills your desired goal. Together they turn a forest of jargon into a path you can stroll during nap time.
This is just the tip of the ice berg
And all that careful scaffolding is wrapped in a constellation of tiny, almost invisible flourishes. Soft easing animations nudge your gaze exactly where it’s needed—an answer tile pulses once, then settles; a progress dot glides forward with a hush, reassuring you that momentum is real [4]. Each word is chosen for warmth, beginning with “Let’s” or “We’ll”—a deliberate invocation of the we-mindset that invites the app into the parenting team instead of leaving you alone with officialdom [10]. Even the haptic taps feel like a gentle pat on the shoulder, confirming choices without clamoring for attention. Individually, these micro-interactions might pass unnoticed; together they weave a quiet choreography that guides, comforts, and reminds parents that every click, swipe, and pause is shared.
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[2] Bhandari, Upasna; Chua, Wen Yong; Neben, Tillmann; Chang, Klarissa: Cognitive Load and Attention for Mobile Applications: A Design Perspective. In: Human-Computer Interaction. Interaction Platforms and Techniques (Lecture Notes in Computer Science, vol. 9732), International Conference on Human-Computer Interaction, pp. 278–284, First Online 19 June 2016.
[3] Sweller, J., van Merriënboer, J. J., & Paas, F. G. (1998). Cognitive Architecture and Instructional Design. Educational Psychology Review, 10(3), 251–296. ResearchGate
[4] Boyd, K., & Bond, R. (2021). Can micro-interactions in user interfaces affect their perceived usability? Ulster University Research Publication, 1–6. Typeset
[5] Parhi, P., Karlson, A. K., & Bederson, B. B. (2006). Target Size Study for One-Handed Thumb Use on Small Touchscreen Devices. In MobileHCI ’06. Microsoft
[6] Park, Y. S., & Han, S. H. (2010). One-handed thumb interaction of mobile devices from the input accuracy perspective. International Journal of Industrial Ergonomics, 40(6), 746–756. ResearchGate
[7] Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81–97. Wikipedia
[8] Baymard Institute. (2024). Form Design: 6 Best Practices for Better E-Commerce UI. Baymard Institute
[9] Baymard Institute. (2023). Provide “Fully Automatic Address Lookup” — E-Commerce Checkout Usability.
[10] Brewer, Marilynn B.: The Psychology of Prejudice: Ingroup Love and Outgroup Hate? Journal of Social Issues 55(3): 429–444, 2002. DOI 10.1111/0022-4537.00126