A state-based effect would manifest as a “hockey stick” function, i.e., a flat line from confidence responses 1 to 5 and then a disproportionate increase to response 6. We used log-likelihood to estimate the best-fitting

flat line Venetoclax molecular weight (no slope), linear trend, hockey stick function, and combination of linear trend + hockey stick. We then compared the goodness of fit of these functions to the data using hierarchical likelihood ratio tests. Compared to the best-fitting flat line (no slope), the linear trend provided a significantly better fit to the data (χ2 = 4.55, p = 0.03). In contrast, compared to the flat line, the hockey stick function did not provide a better fit (χ2 = 2.16, p = 0.14). Comparison of the Akaike information criterion values for the linear trend and hockey stick function provided moderate evidence in favor of the linear trend (AIC difference = 2.39; Burnham and Anderson, 2002), and adding a hockey stick function to the linear trend did not significantly improve the fit of the latter, as might be expected if this region

showed state-based effects (χ2 = 0.14, p = 0.71). These data therefore provide evidence that activation in the left posterior hippocampus is well-described as linearly tracking strength-based perception. Because the MTL ROIs were LY294002 ic50 identified by contrasting correct “different” and “same” trials, it is important to determine whether the linear trend across confidence is a result of collapsing across “same” and “different” trials when extracting parameter estimates for each ROI (i.e., since “different” trials contribute below a declining number of trials to each confidence bin as confidence decreases). We therefore extracted parameter estimates for the ROIs for only the “different” trials, restricting the analysis to response bins for

which there were enough trials to reliably extract parameter estimates (i.e., confidence responses 4, 5, and 6). A role in strength-based perception would be supported by increased activity from “4” to “5” responses, with no additional increase for state-based judgments based on access to specific details (i.e., “6”s). In contrast, a role in state-based perception would be evident by higher activation for ‘6’ responses than “5” and “4” responses, which should not differ from one another. For all 3 ROIs, activation for the “6” responses was not different from the “5” responses (t(17) = 0.03, p = 0.97, t(17) = 1.07, p = 0.30, and t(17) = 1.31, p = 0.21 for the hippocampus and left and right PHc, respectively), but activation for the “5” responses was significantly greater than for the “4” responses (t(17) = 2.19, p = 0.04, t(17) = 2.19, p = 0.04, and t(17) = 2.14, p = 0.05 for the hippocampus, and left and right PHc, respectively).