The Perception of Causal History

Here are some demonstrations of the various conditions discussed in the following paper:
Chen, Y. -C., & Scholl, B. J. (2016). The perception of history: Seeing causal history in static shapes induces illusory motion perception. Psychological Science, 27(6), 923-930.
This demonstration is provided as an MP4 movie, which can be downloaded or viewed directly in most web-browsers. The movie may be a bit large and choppy, but it should be sufficient to illustrate the basic effect. As a compressed version of the original stimuli, this movie may not preserve the precise spatial and temporal characteristics of the original displays.

Note that to be effective, you may have to download this movie and play it directly from your computer.  
The perception of shape, it has been argued, also often entails the perception of time. A cookie missing a bite, for example, is seen as a whole cookie that was subsequently bitten. It has never been clear, however, whether such observations truly reflect visual processing. To explore this, we tested whether the perception of history in static shapes could actually induce illusory motion perception. Observers watched a square change to a truncated form, with a "piece" of it missing, and they reported whether this change was sudden or gradual. When the contours of the missing piece suggested a type of historical 'intrusion' (as when you poke your finger into a lump of clay), observers actually saw that intrusion occur: the change appeared gradual even when it was actually sudden, in a type of transformational apparent motion. This provides striking phenomenological evidence that vision involves reconstructing causal history from static shapes.

The Basic Effect: Intruded vs. Imposed Contours (1.9 MB)
To begin, cover up the right side of the movie with a hand, and just notice the way in which the white 'star' shape on the left seems to appear all at once, in a momentary flash. Now cover up the left side, view the animation on the right side, and notice the way in which the white shape appears to (very quickly yet non-instantly) move down into the black square, as if it was being pushed into it. To best appreciate the effect, try contrasting the perception of movement of this sort on the left vs. the right.