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. Author manuscript; available in PMC: 2018 Jan 1.
Published in final edited form as: J Exp Psychol Anim Learn Cogn. 2017 Jan;43(1):1–14. doi: 10.1037/xan0000127

Figure 6.

Figure 6

Bootstrapping was performed on the curve fits from Experiment 1 to determine whether the reduction in responding during extinction was itself sufficient to cause a shift in I. A,B, Example data from the boostrapping experiment. To test the hypothesis that a reduction in responding is sufficient to shift I, we generated bootstrap samples by randomly selecting n responses from the real distribution of response times. The value of n corresponded to the number of responses occurring during a particular trial block (Sourcen). The trial block from which response times were drawn is denoted SourceRT. SourceRT could be either block 1 or the same block as Sourcen. The bootstrap samples were fit and the I value calculated as described above. C, Results of the bootstrap experiment. I is expressed as a fraction of the extinction CS duration. In Groups 6 and 12, I did not differ as a function of SourceRT. In Group 24, changes in Sourcen increased I when responses times were drawn from Sourcen but not when all response times were drawn from block 1 only. This pattern confirms that the increase in I during extinction in Group 24 exceeded any change expected purely on the basis of diminished responding.