UX Researchers Reveal Why Carets Are the Safest Choice for Web Accordions and Why Split Menus Fail
In the ever-evolving landscape of digital user experience design, small interface elements frequently hold the power to make or break a user’s journey. Among these UI building blocks, the humble accordion menu remains a staple for organizing large amounts of content, particularly in mobile applications and complex e-commerce navigation bars. However, recent usability research sheds light on a persistent design flaw across the web: the widespread misuse of expand-and-collapse icons. According to comprehensive studies by the Nielsen Norman Group (NN/g), interface designers frequently compromise usability by implementing ambiguous icons, confusing split-button architectures, and unnecessary visual clutter.
The findings offer a definitive roadmap for designers striving to build intuitive interfaces. Most notably, research indicates that the caret is the single most reliable icon choice for indicating accordion functionality, while split menus—where a text label navigates to a new page and an accompanying icon opens a dropdown—consistently alienate and confuse users.
The Anatomy of Accordion Confusion
To understand the current state of UI design, one must examine how users interpret common visual cues. When users encounter a menu item devoid of any icon, psychological expectations are clear and consistent: they anticipate that tapping the element will navigate them directly to a new page. Historically, this pattern has governed web architecture since its inception.
However, as websites grew denser and mobile screens shrank, designers began introducing icons to signal collapsible content regions. This well-intentioned shift introduced a new set of cognitive hurdles. Usability testing demonstrates that users struggle significantly with custom or non-standard icons because these graphics fail to establish an immediate, universally understood mental model. Furthermore, eye-tracking and interaction studies reveal that users tap with near-equal frequency on both the text label and the accompanying icon. This behavioral reality means that an icon choice does not merely serve as a passive visual indicator; it fundamentally dictates the user’s perception of the entire clickable target area, known as the hit zone.
Many modern web designs attempt to overcomplicate this interaction by deploying dynamic arrows and carets that rotate, shift direction, or point inward based on the real-time state of the accordion. Yet, industry standards and user testing suggest that simplicity consistently outperforms over-engineering.
The Perils of Split Menus and Overloaded Icons
One of the most critical warnings emerging from recent UX evaluations concerns the implementation of split menus. In a split-menu architecture, a single list item is bifurcated: clicking the text label directs the user to a category overview page, while clicking the adjacent icon expands the accordion menu.
Usability assessments consistently brand split menus as inherently harmful to user experience. In practice, users rarely parse the subtle visual distinction between the text and the icon hit areas. When a user intends to expand a menu to view subcategories but inadvertently triggers a page navigation instead, frustration ensues. This friction disrupts the browsing flow and increases bounce rates, particularly on mobile devices where precision tapping is physically more demanding.
UX experts recommend a far more reliable pattern: the primary menu item should function exclusively as an accordion toggle, exposing the sub-options upon a single tap. To grant users access to the main category overview page, designers should embed a dedicated "Overview" link directly within the newly expanded sub-menu. This eliminates ambiguity and ensures that every clickable element performs a predictable, singular action.
Beyond split menus, the research highlights the pitfalls of relying on overloaded icons such as plus/minus symbols (+/-) and standard directional arrows. While plus and minus signs are generally understood to denote expansion and collapse, they carry heavy baggage from other digital contexts. A plus symbol frequently signifies saving an item for later, adding a product to a shopping cart, or zooming in on an image. When applied to multi-level navigation trees where multiple tiers remain open simultaneously, plus and minus signs quickly lose their communicative value.
Similarly, directional arrows pointing left, right, up, or down suffer from polysemy. Users may interpret arrows as indicators for scrolling, sliding, pagination, or jumping to a specific page anchor. Because these symbols are tasked with too many divergent responsibilities across modern software, they frequently trigger user hesitation.
The Triumphant Return of the Caret
Amidst a sea of ambiguous arrows and complicated buttons, empirical data points to a clear winner: the caret, or downward-facing triangle.
NN/g research indicates that the standard downward-facing caret is the safest and most universally understood icon for representing collapsible content. When a user interacts with the element and the accordion opens, transitioning the caret to point upward or sideways provides an immediate, unambiguous visual confirmation of the state change. Major global platforms, ranging from international logistics providers like DHL to scholarly search engines like Lens.org, have increasingly standardized around this pattern to streamline mobile and desktop navigation.
Furthermore, the research provides a definitive rule for handling pure text links within navigation structures: if an element’s sole purpose is to take the user to a new page, designers should omit icons entirely and rely on traditional underlining. While underlining text links may seem visually dated to some modern minimalists, it remains the most universally recognized affordance on the internet. It requires zero cognitive load and functions flawlessly across all demographics and digital literacy levels.
Broader Implications for Digital Product Design
The ongoing discourse surrounding accordion icons and navigation patterns highlights a broader truth in software and web engineering: innovation should not come at the expense of established mental models. As digital products become increasingly complex, designers face constant pressure to introduce novel visual languages to differentiate their interfaces. However, usability data consistently demonstrates that users prefer consistency and predictability over novelty.
When organizations strip away redundant arrows, eliminate confusing split-menu patterns, and adopt standardized markers like the caret, they directly improve accessibility and reduce task completion times. Simplifying navigation hierarchies ultimately respects the user’s time and cognitive bandwidth. As the digital design community continues to analyze user behavior through rigorous empirical research, the prevailing philosophy remains clear: when it comes to interface design, simpler is almost always better.
