Testing Quantum Models of Conjunction Fallacy on the World Wide Web


The ‘conjunction fallacy’ has been extensively debated by scholars in cognitive science and, in recent times, the discussion has been enriched by the proposal of modeling the fallacy using the quantum formalism. Two major quantum approaches have been put forward: the first assumes that respondents use a two-step sequential reasoning and that the fallacy results from the presence of ‘question order effects’; the second assumes that respondents evaluate the cognitive situation as a whole and that the fallacy results from the ‘emergence of new meanings’, as an ‘effect of overextension’ in the conceptual conjunction. Thus, the question arises as to determine whether and to what extent conjunction fallacies would result from ‘order effects’ or, instead, from ‘emergence effects’. To help clarify this situation, we propose to use the World Wide Web as an ‘information space’ that can be interrogated both in a sequential and non-sequential way, to test these two quantum approaches. We find that ‘emergence effects’, and not ‘order effects’, should be considered the main cognitive mechanism producing the observed conjunction fallacies.

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  1. 1.

    Emergence of new meanings in conceptual combinations closely resembles the ‘holistic quantum computational semantics’ developed by Dalla Chiara et al., where the meaning of a sentence is not attributed to the compositional meaning of each word but, rather, to the holistic relations between these words (see, e.g., [22, 23]).

  2. 2.

    More precisely, in our searches for words and combination of words we have always excluded the following four very unusual Italian words: ‘barbablu’, ‘miseriaccia’, ‘acciderpoli’ and ‘tristobello’.


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Correspondence to Sandro Sozzo.

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Aerts, D., Arguëlles, J.A., Beltran, L. et al. Testing Quantum Models of Conjunction Fallacy on the World Wide Web. Int J Theor Phys 56, 3744–3756 (2017). https://doi.org/10.1007/s10773-017-3288-8

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  • Quantum cognition
  • Conjunction fallacy
  • Emergent reasoning
  • Meaning bond
  • World Wide Web