System initiative visibility and explanatory support depth shape older adults’ trust and decision acceptance in smart homes

As smart homes become more autonomous, older adults may experience uncertainty when system actions occur without clear cues about what changed, whether the system initiated the action, and whether intervention remains possible. Although transparency and explanation are often proposed as remedies, less is known about how action visibility and explanatory information work together for older users. This study used a 2 × 3 between-subjects experiment with 96 older adults to test two interface-communication factors: system initiative visibility, defined as whether the interface explicitly signals that the smart-home system has initiated an action, and explanatory support depth, defined as the amount of rationale provided for that action. The outcome variables included understandability, trust, perceived control, technology anxiety, decision acceptance rate, and response time. Participants completed system-initiated smart-home tasks; their subjective ratings, decision acceptance, and response time were recorded. Higher system initiative visibility was associated with higher understandability, trust, perceived control, and decision acceptance, as well as lower response time and technology anxiety. Explanatory support depth showed more selective effects, with moderate explanation generally producing the most balanced pattern across trust, decision acceptance, and response efficiency, whereas detailed explanation did not consistently provide additional benefit. Interaction patterns for trust, and more cautiously for decision acceptance, suggest that explanation may partly compensate when system initiative cues are weak. Overall, the findings provide preliminary support for a bounded semantic compensation account and suggest that autonomous smart-home interfaces for older adults should prioritize clear system-action cues with concise, layered explanations.