“A study by Psychology researchers at the University of Warwick has found a radical 50/50 split in how people decide ‘What makes two things seem similar?.” according to this report at ScienceDaily.
His first experiment using the word “similar” found that 31% of the people chose a physical feature based similarity (for instance cake and cookie) whereas 46% went for a theme based similarity (such as cake and birthday). The researchers tried changing the word “similar” to “like” to try and rule out any strange semantic effect but this time 31% still selected a physical based likeness (such as fur and hair) whereas this time 57% selected a themed likeness (such as fur and coat).
[Further experimentation] left an overall split in the population of around 50% who were more thoughtful and chose a physical feature based similarity (such as net and rope) and another 50% for who always went for the thematic option (net and fish) whether they used instinct or deeper thought.
The article notes that this has implications for split product placement in grocery stores and the use of keyword advertising on web pages.