Word frequency and receiver operating characteristic curves in recognition memory: evidence for a dual-process interpretation.

Dual-process models of the word-frequency mirror effect posit that low-frequency words are recollected more often than high-frequency words, producing the hit rate differences in the word-frequency effect, whereas high-frequency words are more familiar, producing the false-alarm-rate differences. In this pair of experiments, the authors demonstrate that the analysis of receiver operating characteristic (ROC) curves provides critical information in support of this interpretation. Specifically, when participants were required to discriminate between studied nouns and their plurality reversed complements, the ROC curve was accurately described by a threshold model that is consistent with recollection-based recognition. Further, the plurality discrimination ROC curves showed characteristics consistent with the interpretation that participants recollected low-frequency items more than high-frequency items.</p

Strategy use in question-answering: memory strength and task constraints on fan effects.

Department of Psycholog

Procedural learning and associative memory mechanisms contribute to contextual cueing: Evidence from fMRI and eye-tracking.

<p>Using a combination of eye tracking and fMRI in a contextual cueing task, we explored the mechanisms underlying the facilitation of visual search for repeated spatial configurations. When configurations of distractors were repeated, greater activation in the right hippocampus corresponded to greater reductions in the number of saccades to locate the target. A psychophysiological interactions analysis for repeated configurations revealed that a strong functional connectivity between this area in the right hippocampus and the left superior parietal lobule early in learning was significantly reduced toward the end of the task. Practice related changes (which we call "procedural learning") in activation in temporo-occipital and parietal brain regions depended on whether or not spatial context was repeated. We conclude that context repetition facilitates visual search through chunk formation that reduces the number of effective distractors that have to be processed during the search. Context repetition influences procedural learning in a way that allows for continuous and effective chunk updating.</p

The effect of distinctive visual information on false recognition

Using the false memory paradigm (Deese, 1959), recently revived by Roediger and McDermott (1995), we examined the effect on true and false recognition of presenting study items in unusual looking fonts. In one condition, each font was associated with a single study item. In a second condition, each font was presented 12 times per study list, randomly distributed across several themes. In a third condition, each font was presented 12 times in the study list, and was associated with a particular study theme. False recognition levels were lowest when there was a unique association between each font and a single study item, whereas false recognition levels were highest when all items from a theme were presented in the same font. Further, the effects of font condition on false recognition of lures maintained when font condition was manipulated within participants and lists. These results, taken together, are inconsistent with theories proposing that false recognition reduction is the product of global shifts in response strategies across conditions (e.g., Schacter, Israel, & Racine, 1999). However, perspectives highlighting the effects of memory based processes on true and false recognition provide an adequate account.</p

Moses Illusion: Implication for Human Cognition

When asked, "How many animals did Moses take on the Ark?" most people respond, "two", even though they know that it was Noah, not Moses, who took the animals on the Ark. When a term in a sentence or a question is replaces by a semantically similar but incorrect term, people have difficulty in detecting the distortion. This tendency to overlook distortions is known as the Moses illusion.</p

Metacognition in Strategy Selection

Many researchers believe that metacognitive processes regulate strategy selection. Another common assumption is that metacognitive processes, such as strategy selection, entail conscious processing or decision making. In this chapter, we examine whether conscious awareness is a critical aspect of strategy selection. We review evidence that first establishes that strategy selection varies both across and within individuals in response to dynamic features of the environment. Then, we present evidence that strategy adaptation can occur without (a) conscious consideration of different strategies or (b) conscious awareness of factors influencing one’s strategy use. Specifically, shifts in strategy use occurred when people seemed to be unaware (a) that there were shifts in their strategy use or (b) that there were changes in the characteristics of the environment that, nonetheless, affected their strategy use.</p

He Who Is Well Prepared Has Half Won The Battle: An fMRI Study of Task Preparation.

The neural mechanism underlying preparation for tasks that vary in difficulty has not been explored. This functional magnetic resonance imaging study manipulated task difficulty by varying the working memory (WM) load of the n-back task. Each n-back task block was preceded by a preparation period involving a screen that indicated the level of difficulty of the upcoming task. Consistent with previous work, activation in some brain regions depended on WM load in the task. These regions were used as regions of interest for the univariate and multivariate (classification) analyses of preparation periods. The findings were that the patterns of brain activation during task preparation contain information about the upcoming task difficulty. (1) A support vector machine classifier was able to decode the n-back task difficulty from the patterns of brain activation during task preparation. Those individuals whose activation patterns for anticipated 1- versus 2- versus 3-back conditions were classified with higher accuracy showed better behavioral performance on the task, suggesting that task performance depends on task preparation. (2) Left inferior frontal gyrus, intraparietal sulcus, and anterior cingulate cortex parametrically decreased activation as anticipated task difficulty increased. Taken together, these results suggest dynamic involvement of the WM network not only during WM task performance, but also during task preparation.</p

Another source of individual differences: strategy adaptivity to changing rates of success.

This article explores an alternative approach to the study of individual differences of cognitive function-- that people may have the same strategies but differential ability to adaptively select among them in response to success and failure feedback from the environment. Three studies involving the complex and dynamic Kanfer-Ackerman Air Traffic Control Task (P. L. Ackerman & R. Kanfer, 1994) demonstrate (a) that individuals do differ systematically along this strategy adaptivity dimension, (b) that those differences have important consequences for overall task performance, and (c) that the differences are primarily associated with reasoning ability and working-memory capacity.</p

How midazolam can help us understand human memory: Three illustrations

Department of Psycholog

Memory for pictures: Sometimes a picure is not worth a single word

Although there are some phenomena in memory that are poorly understood, it is generally accepted that an item studied as a picture will be better remembered than an item studied as a word. </p