Delay-interval illumination changes interfere with pigeon short-term memory.

Tranberg et al. (1980) worked with pigeons on a short-term memory game. The birds had to pick the key that matched a color they just saw.

Between the color and the choice, the lab lights were turned off or on. The team wanted to know if this harmless change hurt memory.

When the lights changed during the wait, the birds picked the wrong key more often. Their matching scores dropped below normal.

The simple light switch acted like static on a radio. It did not erase the memory, but it made the signal harder to hear.

Shimp (1976) showed pigeons can remember the order of their own pecks for several seconds. K et al. add that this memory is fragile if the room changes.

Parmenter (1999) warned that what looks like forgetting may just be stimulus confusion. The 1980 light-shift data support that idea: the birds erred because the context changed, not because time passed.

Green et al. (1987) found that extra cues help pigeons learn faster. K et al. flip the coin: an unplanned cue hurts memory, even when it has no meaning.

Your client’s room is their delay interval. Turning lights off, opening blinds, or moving furniture can muddy recent cues. Keep the physical setting steady during teach-back, recall, or DTT waits. If you must change something, re-present the sample quickly to refresh the correct response.