Is that a friendly (woolly, stingy) face I see?

Humans see faces everywhere. We see a face in the craters of the moon, in wall sockets, sideways in punctuation :-) and just about anywhere else two dots and a line are arranged in even approximately the same positions as two eyes and a mouth.

Don't those drawings of outlets look like faces?

Don’t those drawings of outlets look like faces?

Once we recognize something as a face, we process it differently from other visual stimuli. Certain parts of the brains are triggered preferentially by faces. We are especially good at perceiving faces: we can pick out matching faces faster than matching abstract patterns, and distinguish non-matching faces more easily than other images. This only works, however, when our brains recognize the faces as faces: if you flip faces upside-down, they no longer trigger the “face” switch for us, and we become much worse at distinguishing them. The same thing happens if you digitally scramble facial features, so that there’s an ear in the middle and an eye on the chin and a mouth slanting across the forehead, or any other mix-up that makes the face no longer be arranged like a face. Our brains are specialized to perceive face-shaped patterns much better than other patterns.

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Bugs of the field 2014: dragonflies & spiders

Whoops – I forgot to post these for a while. Here are some photos from last summer of dragonflies and spiders: charismatic, often beautiful, and highly-effective hunters that make me glad I am much bigger than they are.

Male white-faced meadowhawk

Male white-faced meadowhawk

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Nudibranchs defend themselves with their food

Nudibranchs, or sea slugs, are descended from animals with protective shells like those of modern snails. Nudibranchs have lost that shell, leaving them potentially vulnerable: squishy morsels in an ocean full of hungry things. But nudibranchs have some tricks to avoid becoming someone else’s meal: they use their own food to protect themselves.

Hermissenda crassicornis may not have a shell, but he is well-defended. Photo by M. LaBarbera

Hermissenda crassicornis may not have a shell, but he is well-defended.
Photo by M. LaBarbera

One trick is to steal the defenses of your prey. Many nudibranchs eat stinging animals like hydroids and anemones. These animals use specialized stinging cells to catch their own prey and to defend themselves.

Hydroids. The stinging cells are on the ends of the long tentacles, waiting to catch prey. Photo by M. LaBarbera

Hydroids. The stinging cells are on the ends of the long tentacles, waiting to catch prey.
Photo by M. LaBarbera

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Velella velella! Or, falling off the edge of the world

They were strewn all along the beach, these transparent, tripartite things. At first glance they looked like plastic trash, but they felt organic in my fingers.

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Fortunately I happened to be beachcombing with a world expert on marine invertebrates. “Ooh,” he said, “Velella!”

Velella velella, or by-the-wind sailor: a living sailboat, a jellyfish on a stiff frame. In their preferred state, i.e. when not washed up on beaches, these animals float on the ocean surface with their tentacles just below the water, to catch food, and their upright sails above the water, to catch the wind.

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