Table 1.
Groups and filter systems used for skylight manipulation.
| Group | Icon | Conditions | Analyses |
|---|---|---|---|
| DD |  |
Interior workers that had not yet performed learning walks (excavated in the dark using red light); | Neuroanatomy |
| UV-Block with sunshade (UVBS) |  |
Three days of learning walks under a UV-light impermeable filter (Plexiglas (Gallery) 0A570 GT, Evonik Performance Materials GmbH, Essen, Germany) blocking 99.7% of the light below 420 nm with a sunshade, to additionally disguise the position of the sun; | Neuroanatomy Gaze direction |
| Diffusor (Dif) |  |
Three days of learning walks under a diffusor that lets UV-light pass (Plexiglas (GS) 2458 SC, Evonik Performance Materials GmbH, Essen, Germany), but diffuses any polarization pattern in the skylight; | Neuroanatomy |
| Polarization filter (P) |  |
Three days of learning walks under a polarization filter (OUV6060-C—HNP’B replacement, Knight Optical Ltd., Harrietsham, United Kingdom) that lets UV-light pass, but provides an artificial linear, fixed polarization pattern; | Neuroanatomy Gaze direction |
| UV100 |  |
Three days of learning walks under a UV-light permeable Plexiglas (Plexiglas (GS) 2458, Evonik Performance Materials GmbH, Essen, Germany), as a control for the setup; | Neuroanatomy Gaze direction |
| No filter |  |
Three days of learning walks under natural conditions, as a control for the experiment; | Gaze direction |