The brain freezes under shock: what do we actually know? — separate note

Three meanings not to confuse

Everyday “shock” can mean surprise or feeling unable to act. Medical shock is an urgent physical condition. Acute stress reactions may include emotional, cognitive, behavioural and bodily responses; only a professional can assess symptoms and diagnosis.

What studies show

A meta-analysis of 51 experiments found average impairment in working memory, flexibility and interference control, but improved response inhibition. A decision review reports inconsistent results and moderators including task, stressor, biological response and personal characteristics.

Why it is not universal

Laboratory averages do not predict one episode. Some people slow down and others act automatically; training, familiarity, pain, sleep, disability, language and context may alter performance.

From evidence to cautious design

W3C recommends clear language, predictable interfaces, identifiable controls and step-by-step instructions. These are inclusive choices; they neither prove universal impairment nor permit diagnosis from behaviour.

Verification matrix

Use this as questions, not a diagnostic test.

Checklist and limits

Remove avoidable steps, use explicit labels, keep confirmation against accidental taps and alternatives such as calls or SMS. Test with real users. My Safe Circle does not detect shock or events, call emergency services automatically, or guarantee delivery or action.

Concrete example 1 under acute stress. With recognition, the option is present: someone sees “SOS”, “ALL OK” or “I need help” and compares it with their intent. Recall means remembering that a particular icon, long press, sequence or menu item produces an effect. The recognition-over-recall heuristic encourages visible objects, actions and choices. In practice, This is design guidance, not a law that recognition is always easy. A word may be unfamiliar, a label too small, a translation unnatural or two choices too similar. Familiarity, vision, attention, literacy, language, assistive technology and context affect the result. In practice, For a safety control, consequences matter too. Recognising its text does not reveal who receives it, whether location is included, whether a call starts or how to cancel. Put those facts where they are needed rather than relying on an explanation read weeks earlier. This example does not turn an alert into understanding or action: when the route is unsuitable, use a call, the second contact or the agreed local service.

When the tool is not useful 2 under acute stress. The W3C “Use Clear Visible Labels” pattern recommends common, understandable words, visible labels beside their controls and support for assistive technologies. It explains why missing or unclear labels can especially affect people with cognitive, memory or executive-function difficulties, and calls for user testing where the association is not immediate. In practice, “Label in Name” connects visible text with the accessible name. If someone sees “Ask for help” but speech input knows the control by a different name, interaction may fail or surprise them. The visible words should therefore be included in the accessible name under the applicable criterion and techniques. In practice, “Consistent Identification” and predictability guidance call for components with the same function to be identified consistently. Stability does not forbid improvement, but changing wording, colour, position and behaviour together makes prior learning harder to transfer. This example does not turn an alert into understanding or action: when the route is unsuitable, use a call, the second contact or the agreed local service.

Examples, counterexamples and fallback. Example: during calm rehearsal a person understands the route, yet an unexpected event may require clearer labels and less simultaneous information. Start with a concrete event, define an observable outcome and name a lead and backup only after both have accepted the role. Rehearse on the real device at a calm time with ordinary settings, correcting what actually happens without assigning ability or intention.. Research describes variation in attention and memory under stress, not one universal response or an individual diagnosis. Rehearse on the real device at a calm time with ordinary settings, correcting what actually happens without assigning ability or intention. Connectivity, battery, notifications and human availability change; retain calling, SMS or paper instructions as an independent second route.. Confirmation may prevent errors in a consequential action; removing it for speed is not always safer. Connectivity, battery, notifications and human availability change; retain calling, SMS or paper instructions as an independent second route. Collect only necessary data, review consent and contacts after changes, and call local services directly for concrete immediate danger.. An app is unnecessary when a familiar system control or call is more accessible; rehearse without simulating danger. Collect only necessary data, review consent and contacts after changes, and call local services directly for concrete immediate danger. Start with a concrete event, define an observable outcome and name a lead and backup only after both have accepted the role.

• Real example defined
• Counterexample considered
• Lead and backup agreed
• Real-phone rehearsal
• Second channel available
• Tool limitation explicit

Severe physical symptoms or immediate danger require local medical or emergency services.

Frequently asked questions