Interview: Vincenzo Santarcangelo

Students: I would like to know more about the experiment which compares the different perceptions of humans and animals. Isn’t it possible that animals simply perceive in a different way from us? Is it possible that maybe they also perceive the depth but, because the sense of touch is predominant on the others, they continue to walk?

Vincenzo Santarcangelo: Yes, is exactly like this. They probably prefer to touch the tool that they used to create the visual illusion in the experiment. So when they touch it (of course it depends from the species) normally they don’t care about the illusion anymore and they go on.

S: So which is the role of the different senses in our perception? Is a question of balance between them?

VS: Yes, this is a crucial point, there is of course a co-implication of all the senses. The balance that is provided by the vestibular and the inner ear together is the only way to ensure equilibrium. All our senses have to co- operate to give back the perception of depth, for example, or the sense of risk so that if you see a cliff, a visual cliff, you perceive directly the risk of surpassing it. And this sense changes a lot according to the different species. Indeed for this experiment there are as many results as many where the species involved.

Ecology

Environmental enrichment: habitat and measurement of space

S: According to James Gibson, perception is direct and not subjected to hypotheses testing. He argues that our environment gives us enough information to make sense of the world around in a direct way and there is absolutely no need for interpretation. On the other hand there is a controversial point of view stating that the presence of visual illusions cannot be underestimated. What is your opinion about these statements? Do you think that the perception of the real world is based only on “what you see is what you get?

VS: Yes, according to Gibson “what you see is what you get”; perception is direct because environment gives us enough information to make sense of the world around us. This is possible because perception is to be considered at its own level, distinct from sensation. Visual illusions can be explained at the level of sensation, but also when you see, say, a stick in the water, at the level of perception you are still picking information from the ambient. You can see this interesting post about Gibson and illusion, and mention the famous Gibson-Gombrich debate about pictures and illusions.

S: As we are working on the project “Milano Animal City” what is the best way to have a non-anthropocentric view to the environment in order to make the city also for the animals, along with humans?

VS: One could extrapolate a non-anthropocentric view from Gibson’s books, although he never explicitly distinguishes between human and non- human animals – but it’s not an easy operation. I think it’s easier to compare von Uexkull and Gibson’s concepts of niches, environment, ecology, animals…

S: Affordances represent in a way the different possibilities an environment offers to an animal. Would a human interaction that modifies this specific environment by offering, on purpose, more of the same affordance, result in a higher percentage of animal to unconsciously take this affordance? Is it possible to increase the affordance ratio of an animal by modifying its environment?

VS: Yes, it is possible. The affordances are relational properties of the environment, so by modifying it, the animal’s behaviour (the animal/environment interaction) the affordance ratio will surely increase. See this paper, and consider also the concept of “effectivities” as outlined by Shaw, Turvey, Mace (1982).