Visual Illusions

Mixing Memory

Category archives for Visual Illusions

In keeping with the theme of illusions that result from crossmodal interactions, this week’s illusion is the ventriloquism effect, first reported by Howard and Tempelton in 1966. As you can probably tell from the name, the ventriloquism effect involves visual information influencing where we think sounds occur, like the moving mouth of a ventriloquist’s dummy…

Last week, I talked about the sound-induced flash illusion, in which presenting a single flash with two or more auditory beeps caused people to see two or more flashes. This week, a study showing that the same effect can be obtained by replacing the beeps with touches. Here’s the setup (unfortunately, I can’t show you…

You may have seen this illusion in a post from earlier in the week over at Cognitive Daily, but I thought I’d say a little bit more about it, and talk about a related illusion. First, click play (from Sham’s demo site) If the illusion is working — Dave at Cognitive Daily had a bit…

I was reminded of this illusion by the Seed Daily Zeitgeist yesterday. In order to get the full effect, I’ll show you one set of photos here, and the rest of the post will be below the fold. The first are from Schwanginer et al. (2003)1: They look pretty normal, right? Now look at these:

This week’s visual illusion is related to Mach bands, and similar in some ways to the watercolor effect. It’s called the Craik-O’Brien-Cornsweet effect (or just the Cornsweet effect)1. This is the best example I’ve ever seen (from here): What you should see is a dark square over a light square (almost white). Now take your…

Cool Visual Illusions: Mach Bands

Discovered in the 1860s by Ernst Mach (hence the name), Mach Bands are actually a set of interrelated phenomena. Take a look at this image: From here The individual bands should appear as gradients, and they may even appear to be curved. In fact, they are all solid colors. Now look at this one: From…

Here is an illusion that was discovered relatively recently. Take a look at this (from here): You should see two figures with a purple outter border and an orange inner border. What color is the interior of the figure? It probably looks like it’s orange, though a lighter shade of orange than the inner border.…

Neural Adaptation for Gender

In yesterday’s post on afterimages and aftereffects, I mentioned that demonstrations of neural adaptation for a particular feature (in the post, I used the examples of color and motion) is generally taken as evidence of the existence of specific neurons or groups of neurons that detect/process that feature. With motion or color, which are very…

Most of you have probably seen this before, but if you haven’t, look at the flag for 30 seconds (if it doesn’t work with 30, try 60), and then look at the white space underneath it. You should see a red, white, and blue flag when you look at the white space. That is a…

Cool Visual Illusions: Depth Inversion

As you all know, I love visual illusions, and this may be one of my favorites. This picture is pretty small (go here for a bigger version), but you should be able to figure out what’s going on by watching it for a moment. Notice that as the face flips over, you briefly see the…