Temporal vocabulary dynamics

When did the canonical r/Aphantasia vocabulary enter the lexicon, and how has uptake evolved 2015 → 2026?

Methodology

• Source: reddit/data/temporal_vocabulary.csv, generated by pipeline/src/aphantasia_pipeline/analysis/temporal_vocabulary.py.
• Counted from primary post and comment text (not chunk context) so that a term in a parent post doesn't inflate its descendant comments.
• Both source_matches (one row per primary post/comment containing the term) and author_weighted (distinct authors using the term that year) are reported. Author-weighted is the more honest "how many people" estimate.
• The CSV combines vocabulary series (technical/folk terms like aphantasia, mind's eye, SDAM) with metaphor_family series (curves for the 12 metaphor families documented in reddit/metaphors/).
• 2026 is a partial year (data through 2026-05-06) and should not be compared directly with 2015–2025.
• No comparative claims about the rate of vocabulary growth vs other communities — we have no control corpus.

When each canonical term first appeared

Year of first non-zero primary-source match:

Peak years and author reach

Author-weighted is the more conservative "how many people" estimate:

What this shows

1. The lexicon stabilises fast. Of 10 canonical terms, 8 first appear by 2017 and all 10 by 2018. After 2018 the community is deepening an existing vocabulary, not coining new terms. This is the opposite pattern to a niche-coinage community — the vocabulary was effectively complete by year 4.

2. Most terms peak in 2024. Six of ten terms (aphantasia, aphant, aphantasic, SDAM, hyperphantasia, anendophasia, anauralia) hit their highest year-volume in 2024. This is a community-wide visibility surge that almost certainly reflects external events: the John Green tweet (Oct 2023, peak in 2024), the BBC/CBC coverage, and the Zeman 2024 TICS and Pearson lab outputs.

3. mind's eye peaked in 2021 and has declined since. This is the only term whose peak year is not 2024. After hitting 1,667 source matches in 2021, the term contracted as the community's canonical vocabulary shifted toward the precise terms (aphantasia, aphant) and away from the older folk-technical idiom. Match this against reddit/metaphors/mind_eye.md's observation that the term is "increasingly subject to meta-skeptical argument that aphantasia is an artefact of taking the metaphor too literally" — community discussion has been re-evaluating the mind's eye framing while moving past it.

4. hypophantasia is the only term still rising in 2025. Every other term peaked in 2023 or 2024 and is steady or declining. hypophantasia is at 534 source matches in 2025 — its highest year — and its growth is consistent with the recent published finding (Neuropsychologia 2026) that very weak imagery may carry more mental-health distress than no imagery at all. The community is actively converging on this distinction in real time.

5. The clinical-import vocabulary (SDAM, anauralia, anendophasia, prosopagnosia) collectively grew at ~10× from 2018 to 2024. Even after factoring in that the subreddit itself grew over that period, these terms' author-weighted peaks (612, 114, 241, 140 respectively) show real uptake — they're not vocabulary aspiration, they're working terms users apply to their own experience. The four-way decomposition (visual / auditory / inner-voice / autobiographical) the brief's §7 wanted from a future analysis is already in the vocabulary.

6. The author-weighted gap between aphantasia (peak 4,735 authors) and the next term (aphant at 1,752) is large. The majority of authors use the formal noun and a sizeable minority use the community shorthand. mind_eye at peak reached 978 authors (~5–6% of the year's active base) — a useful folk term, but not as universal as the disease-name itself.

Cross-reference: metaphor families over time

The same CSV includes metaphor-family curves. Notable patterns:

• The technical metaphor families (computer_software_render, screen_display_monitor_lcd, terminal_gui_cli) all peak in 2023–2024 alongside the broader aphantasia peak — they grew with the community, not against it.
• terminal_gui_cli peaks at only 49 source matches / 30 authors in its biggest year — the niche framing's whole career is small.
• ai_tools family (regex for ChatGPT/DALL-E/LLM/etc.) is the only metaphor family whose peak year is 2024–2025 with steep growth from 2022 onward (4 matches in 2017, 716 in 2024). This is the clearest "AI/tools rises after 2022" signal the brief's §10 anticipated.

What this answers and doesn't

Answers the brief's §10 (Temporal dynamics):

• When did terms like aphant, mind's eye, and specific metaphors become common? — All canonical terms by 2018; volume peaks 2024 except mind_eye (2021) and hypophantasia (still rising 2025).
• Does AI/tool discussion appear as a later shift? — Yes; AI-tools family is the only metaphor family with 2024–2025 peaks and steep post-2022 growth.

Does NOT answer:

• Whether individual repeat posters' self-descriptions shift over years. The temporal CSV is aggregate; tracking individual authors across years requires a longitudinal join we have not done.
• Whether vocabulary uptake leads or lags external events (academic publications, viral content). That requires event-aligned segmentation.
• Whether the mind_eye decline is a vocabulary obsolescence or just absorbed into newer terms (aphantasia, aphant).

See also

• reddit/data/temporal_vocabulary.csv — the underlying time-series.
• reddit/data/metaphor_year_counts.csv — metaphor-family year curves only.
• reddit/timeline.md — coarse per-year volume + dominant sub-themes.
• reddit/metaphors/mind_eye.md — the folk-term-under-pressure analysis that this file's finding #3 reflects.
• reddit/research_vs_reddit/03_recent_research.md — the hypophantasia-mental-health paper this file's finding #4 anticipates.