Associative retrieval processes in the human medial temporal lobe: hippocampal retrieval success and CA1 mismatch detection

Hippocampal subfields CA(3) and CA(1) are hypothesized to differentially support the generation of associative predictions and the detection of associative mismatches, respectively. Using high-resolution functional MRI, we examined hippocampal subfield activation during associative retrieval and during subsequent comparisons of memory to matching or mismatching decision probes. Activity in the dentate gyrus/CA(2/3), CA(1), and other medial temporal lobe subregions tracked associative retrieval success, whereas activity in CA(1) and the perirhinal cortex tracked the presence of associative mismatches. These data support the hypothesis that CA(1) acts as a "comparator," detecting when memory for the past and sensory input in the present diverge.     

Individual Characteristics of Political Leaders and the Use of Analogy in Foreign Policy Decision Making

The linkages between individual characteristics of political leaders and their usage of historical analogy during foreign policy decision-making episodes were examined. The individual characteristics studied were conceptual complexity and policy expertise, while usage of analogy was studied in terms of the sophistication and source of historical comparisons. The great majority of the analogies used by low-complexity individuals were nonsophisticated, whereas high-complexity individuals consistently used more sophisticated analogies. Low-complexity individuals drew analogies solely from their own generational and cultural context, while high-complexity leaders drew their analogies from a wider range of sources. More expert leaders drew from their personal experiences to a marginally greater degree than less expert individuals but, interestingly, both types of individual relied on generally available rather than personally experienced events for their analogies. The value added of the approach is to demonstrate that different types of leaders use history differently during political decision making.