Make a results paragraph for the results of the experiment. The results can be found below.

The Poggendorff Illusion: The Poggendorff illusion is a geometrical-optical illusion that involves the misperception of the position of one segment of a diagonal line that is blocked by an intervening shape. One of the factors that influences the strength of the illusion is how far about the vertical lines are located. Typically, the greater the separation, the greater the illusion. This experiment tests this phenomenon by showing three different degrees of separation among the verticals: narrow, medium, and wide. This experiment also allowed us to evaluate whether the illusion is affected by the length of the diagonal lines and whether these factors interact to alter the strength of the illusion.

Hypothesis: The greater the separation between the vertical lines, the greater the Poggendorff illusion. No prediction was made about the influence of the length of the diagonal on the strength of the illusion. Likewise, no prediction about the interaction between the separation of the verticles and length of the diagonal was made.

There were 6 different stimuli presented: 1) Short diagonal with narrow separation between verticles 2) Short diagonal with medium separation between verticles 3) Short diagonal with wide separation between verticles 4) Long diagonal with narrow separation between verticles 5) Long diagonal with medium separation between verticles 6) Long diagonal with wide separation between verticles.

IV: Separation of Verticles Narrow Medium Wide

IV: Length of Diagonal Short Long

DV: Deviation (in pixels) between the height of the adjusted diagonal line segment and the height of a true collinear diagonal line segment. A negative value indicates that the right diagonal was placed too low, which is the placement that reflects the Poggendorff illusion.

Analysis: A 2 (length of diagonal) x 3 (separation of verticles) two-way repeated-measures ANOVA

RESULTS What was found?

Indicate if the results were or were not significant for each main effect and then the interaction

Provide statistical verification for the main effect of length of diagonal

[Eg., F(dfnumerator, dfdenominator)= 5.465, p=.037].

Refer reader to figure and explain results of how the length of the diagonal ONLY affected the illusion. Provide statistical verification for the main effect of separation of verticles

[Eg., F(dfnumerator, dfdenominator)= 8.222, p<.001].

Refer reader to figure and explain results of how the separation of verticles ONLY affected the illusion.

Provide statistical verification for the interaction between length of diagonal and separation of verticles

[Eg., F(dfnumerator, dfdenominator)= 19.568, p<.001].

Refer reader to figure and explain how the impact of the separation of verticles changes based on the length of the diagonals

Example of what is needed:

The results of the two-way repeated measures ANOVA revealed that there was no significant main effect of part location on participants' reaction times (F(1,29) =.04, p > .05, p 2 = .001). Participants' performed similarly when verifying inside (mean = 997.39ms) and outside parts (mean = 988.56ms). And while descriptive statistics revealed that participants' mean response times were slightly faster when taking an inside functional perspective (mean = 976.70ms) compared to an outside functional perspective (mean = 1009.25ms), the ANOVA revealed that this difference was not significant (F(1,29) = .87, p = .36, p 2 = .03). In contrast, there was a significant interaction between Part_Location and Perspective (F(1,29) = 4.29, p < .05, p 2 = .13) such that participants were fastest in conditions when the functional perspective and part location matched compared to when they differed (see Table 1 below).

Lafayette's Poggendorff Results