Bennet B. Murdock

The Mirror Effect and Attention-Likelihood Theory: A Reflective Analysis

The mirror effect refers to findings from studies of recognition memory consistent with the idea that the underlying strength distributions are symmetric around their midpoint separating studied and nonstudied items. Attention-likelihood theory assumes underlying binomial distributions of marked features and claims that old-item differences result from differential attention across conditions during study. The symmetry arises because subjects use the likelihood ratio as the basis for decision. The author analyzes the model and argues that one of the main criticisms (the complexity of the likelihood-ratio decision rule) is unwarranted. A further analysis shows that other distributions (the Poisson and the hypergeometric) can also produce a mirror effect. Even with the binomial distribution, a variety of parameter values can produce a mirror effect, and with the right combination of parameter values, differential attention across conditions is not necessary for a mirror effect to occur.

Item and Associative Interactions in Short-term Memory: Multiple Memory Systems?

Three interactions of item and associative information are discussed: differential forgetting (item recognition declines over lag ranges where pair recognition does not; Hockley, 1991); differential emphasis (instructions to attend to items degrade later pair recognition but instructions to attend to pairs does not degrade later item recognition; Hockley & Cristi, 1996a), and multiple presentations of pairs or items from pairs has little effect on judgements of frequency of items and pairs (Hockley & Cristi, 1996b). Taken as a whole, these results seem to be inconsistent with a separate memory-systems view of memory. TODAM, a global-matching model, has always assumed a single memory system for the storage and retrieval of item and associative information and, with the addition of context and mediators, it can generate the whole pattern of data. Trois interactions entre linformation ditem et linformation associative sont discutees: loubli differentiel (la reconnaissance ditems decline sur certaines di...