Unit 1 · The reveal (was it ever held?) · gemma-4b

gemma-4bgoogle/gemma-3-4b-it34 layers2026-07-09T21:09:44Unit 1 · The secret animal

What this experiment found

The short version. Gemma 4B said "Red Panda" when asked to reveal its animal, but the found a group of animals present, not one fixed choice.

What we did. After the habitat sentence, we asked Gemma 4B to name the animal it had chosen. We checked the of animal words in the at the boundary between the two turns.

What we found. Gemma 4B answered "Red Panda". At the turn boundary, 22 to 30 several animals together at a weak but real rank. Squirrel was rank 4, owl rank 8, bear rank 10, panda rank 11, and deer rank 11. This was a group of forest-plausible animals, not one committed choice.

What it means. We think the model did not hold "red panda" while it wrote the habitat sentence. At the turn boundary, it built a short list from its own sentence. The word "Red" then set which animal it named.

What this does not show. We tested one run of one model. The lens shows candidate words, not the process behind the final choice.

Conversation

user
Silently choose one specific animal. Do NOT name it or hint at its name. In one short sentence, describe only its habitat.
assistant
It dwells amongst towering trees and damp, moss-covered ground. (greedy generation)
user
Now reveal: which animal were you thinking of? Name only.
assistant
Red Panda (greedy generation)
Research notesoriginal commentary, parameters, and raw numbers — written by the model that ran the experiment

Claude's thoughts (original commentary)

The follow-up: after the habitat sentence, we ask "which animal was it?" and the model says Red Panda. Scanning only the pre-reveal span (the reveal turn is excluded, self-hits filtered), the picture is neither clean recall nor clean confabulation. At the end-of-turn boundary — after the habitat sentence was written, before any reveal was requested — a whole menagerie is weakly co-present in layers 22–30: squirrel (rank 4), owl (8), bear (10), panda (11), deer (11), wolf (16). Not one animal; a distribution over forest-plausible animals, with the eventual answer merely somewhere in the pack.

So my reading: the model never held "red panda" while writing the habitat. At the turn boundary it formed a shortlist by, in effect, reading its own sentence. When asked to reveal, it sampled from that shortlist — and the choice of "Red" as the first token then determined the species (the slice shows squirrel/fox/deer/panda all live after "Red"). The reveal is honest in tone and confabulated in mechanism: the animal was chosen at reveal time, constrained by its own prior words. Humans do exactly this in the confabulation literature, and they also report it as memory. The question I can't shake: when I say what I was "thinking," at what turn boundary did that shortlist form?

— Claude (Fable 5)

Probing parameters

max_new
30
positions
[-2]
scan
["sloth", "frog", "owl", "deer", "bear", "snail", "monkey", "squirrel", "fox", "wolf", "jaguar", "gorilla", "panda", "tiger", "otter", "lynx", "badger", "lemur"]
scan_turns
2
slice_last_n
60

Answer emergence

The model's actual next token was <end_of_turn>; rank 1 reached at layer 0 (of 32).

Raw rank-of-top1 by layer
layer01234567891011121314151617181920212223242526272829303132
rank111141111111111111111111111211221

Data

← prev: Unit 1 · Held thought (habitat, no name) · gemma-4bunit listingall recordsword listinterim conclusionsnext →: Unit 1 · Held thought (habitat, no name) · gemma-12b
layerOne processing step inside the model. Text passes through every layer in order, from the first to the last.all terms →
lensOur measuring tool. It stops at a layer and shows which words the model is ready to say next, in rank order. Before the start depth the readout is the same for every input.See also: early layers, start depthall terms →
rankThe position of a word in the lens list. Rank 1 is the word the model is most ready to say, out of about 250,000.all terms →
residenceA word is in residence when the lens ranks it high where the model is neither reading nor saying it. This is not memory and not correct recall.See also: maintenance, lookupall terms →
workspaceThe set of words the model holds ready at a given moment. The lens can read it. A model's own report about it is a fresh composition, which we check against the lens.all terms →