Illusion news 7

since September 23, 2007


 

The relationship between the "Rotating snakes" illusion and age has been examined several times. Here are additional data from students of a high school and the Ritsumeikan University. The items for answer were "Rotating snakes appear to move well" (score 3), "Rotating snakes appear to move" (score 2), "Rotating snakes appear to move slightly" (score 1), and "Rotating snakes do not appear to move at all" (score 0). As a result, young people tend to see this illusory rotation strongly. <October 17, 2007>



Data from high school students (with one teacher) (October 4, 2007). For scores, see text.



Data from Ritsumeikan University students (October 12, 2007).



The graph shown below displays the combined data that have been collected so far. A strong negative correlation (r = -.46) was found between the Rotating Snakes illusion and age! This does not necessarily mean that the older the observer is, the less visible the illusion. This indicates that some unknown characteristics of this illusion are related to age while this illusion is not related to aging.

For those who do not see the "Rotating snakes" illusion, please do not worry because "no illusion" does not mean anything. It is only one of the individual differences. Please enjoy other illusions!

 

The relationship between the "Rotating snakes" illusion and age has been suspected. Several researchers including me made preliminary surveys, showing positive or negative data. These surveys actually failed to inlude enough number of old people's data.Here I report the result from 56 old observers (more than 60 years old), who attended my lecture held on 20th September, 2007 in the hall for retired people of Amagasaki city, Hyogo-ken, Japan (next to Osaka city). Fifty-six citizens participated, the age ranging between 60 and 88. The items for answer were "Rotating snakes appear to move well" (score 3), "Rotating snakes appear to move" (score 2), "Rotating snakes appear to move slightly" (score 1), and "Rotating snakes do not appear to move at all" (score 0).

The result is shown below. Twelve observers (21%) reported no illusory motion. This proportion is larger than 5% that have been estimated so far. This result agrees with the first survey in VSS2005, USA (May, 2005). But it should be noted that the oldest observer, 88 years old, reported strong motion illusion. <September 23, 2007>


For scores, see text.


If this set of data is combined with a previous one, the total distrubution from young to old is interesting as shown below. People with no illusion increase after the point of the 60 years old. But many people see illusion even if they get still older.

For those who do not see the "Rotating snakes" illusion, please do not worry because "no illusion" does not mean anything. It is only one of the individual differences. Please enjoy other illusions!

Illusion news 6 (June 2007 - September 2007)

Illusion news 5 (January 2007 - May 2007)

Illusion news 4 (January 2006 - December 2006)

Illusion news 3 (January 2006 - May 2006)

Illusion news 2 (April 2005 - December 2005)

Illusion news 1 (2002 - March 2005)





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