Von Uexküll’s A Stroll Through the Worlds of Animals and Men is my favourite reading of the module so far, and it made me think about the relation of depression and the Umwelt, and what better time than our pandemic to think about these things with first-hand experiences.

An animal, or any being’s Umwelt is restricted to what is relevant for that being, as an example, the tick’s Umwelt does not include vision or hearing similar to ours, but rather, it mostly consists of a sense of smell, and not one that us humans employ, but one that is specifically sensitive to one smell, that of butyric acid. Similarly, this idea extends to space and time; a snail’s sense of time is different to ours as is shown with the rubber ball experiment.

Now of course, each individual being has its own Umwelt, although it may share a lot of properties with other members of its species, no two individuals can be said to have the same Umwelt:

In the grounds of my cousin’s castle in Estonia there stoon an old apple tree. A huge lichen had grown on it, which vaguely resembled the face of a clown, but no one had ever noticed this resemblance. One day my cousin had a dozen Russian seasonal labourers brought in, who discovered the apple tree and thereafter gathered before it daily for worship, murmuring prayers and crossing themselves. They declared that the fungus must be a wonder-working image, because it was not made by hand of man. To them, magic processes in nature appeared quite natural. (Von Uexküll, 1992)

This idea seems compatible with my experience with depression, that is, there is a gradual or at times a more instant shift in an individual’s Umwelt when they experience depression or similar states. With this idea in mind, I set out to find such differences with empirical evidence.

Turns out, there is reason to believe that depression might cause changes in our visual perception, perhaps1 seeing with a lower contrast; perception of time as in time dilation or acceleration, as well as a potential reduction in pain perception and more.

In a sense, depression has an Umwelt of its own, one with features that might be shared among those who experience it, or not. The significance of this for me is the hard problem of understanding depression, since it’s an Umwelt of its own, it is not easy for us to see into each others’ Umwelt, and if factors such as culture, language, history and more change our Umwelt and make it harder for us to understand each other, so do states such as depression. One might say the same could be said without the need to refer to an Umwelt, however, the distinction between worlds is important here. The understanding that this is not merely a change to be explained through simple behavioral analysis, but rather it might mean diving deep into another world governed by different rules.

This blog post was originally written for Beyond Solipsism as part of my cognitive science course


  1. Von Uexküll, J. (1992). A stroll through the worlds of animals and men: A picture book of invisible worlds.


  1. I emphasise perhaps, because I personally have doubts about how much can be inferred from brain scan experiments, one might say there is a difference, but what the difference exactly is might not be as reliably derivable.