Task-switching cost and repetition priming: Two overlooked confounds in the fixed-set procedure of the Sternberg paradigm and how they affect memory set-size effects

Subjects performed Sternberg-type memory recognition tasks (Sternberg paradigm) in four experiments. Category-instance names were used as learning and testing materials. Sternberg's original experiments demonstrated a linear relation between reaction time (RT) and memory-set size (MSS). A few later studies found no relation, and other studies found a nonlinear relation (logarithmic) between the two variables. These deviations were used as evidence undermining Sternberg's serial scan theory. This study identified two confounding variables in the fixed-set procedure of the paradigm (where multiple probes are presented at test for a learned memory set) that could generate a MSS RT function that was either flat or logarithmic rather than linearly increasing. These two confounding variables were task-switching cost and repetition priming. The former factor worked against smaller memory sets and in favour of larger sets whereas the latter factor worked in the opposite way. Results demonstrated that a null or a logarithmic RT-to-MSS relation could be the artefact of the combined effects of these two variables. The Sternberg paradigm has been used widely in memory research, and a thorough understanding of the subtle methodological pitfalls is crucial. It is suggested that a varied-set procedure (where only one probe is presented at test for a learned memory set) is a more contamination-free procedure for measuring the MSS effects, and that if a fixed-set procedure is used, it is worthwhile examining the RT function of the very first trials across the MSSs, which are presumably relatively free of contamination by the subsequent trials.

Necessarily a narrator or narrator if necessary: A short note on a long subject words

For (at least) literary narratives I propose to understand “narrator” as follows: An inner-textual speech position from which the current narrative discourse as a whole originates, and from which references to the entities, actions and events that this discourse is about are being made. Through a dual process of metonymic transfer and anthropomorphisation the term “narrator” is then employed to designate a presumed occupant of this position, the hypothesized producer of the current discourse. A narrator is a linguistically indicated, textually projected and readerly identified position whose occupant needs to be thought of primarily in terms of a communicative role, distinct from any actualworld flesh-and-blood (or computer) producer of the text. The paper describes in brief eight different kinds of general considerations (linguistic, philosophical, methodological and general literary-theoretical) which can motivate a narratologist to judge the narrator category/instance as an indispensable or as a merely optional element of his general model of literary narrative. The article concludes with two recent theoretical moves which tend to circumvent the need for such a choice by either re-drawing the narratologist's domain of objects or by redefining the status of the narrator category itself.

Verbal fluency in schizophrenia: The role of semantic clustering in category instance generation

SummaryThe aim of this study was to determine whether schizophrenic patients' impairment in semantic verbal fluency tasks is due to difficulties in organizing their search or, in other words, in organizing output in terms of clusters of meaningfully related words. Consecutive association of words belonging to subcategories of the semantic task was defined as semantic clustering. A categorical verbal fluency task was first administered to 100 healthy subjects and then to 22 schizophrenic patients and 22 healthy subjects matched for sex, age and education. In the normal population, semantic clustering was found to be involved in word generation. A large number of semantic clusters indicated efficient organization of semantic knowledge and led to better word production. Schizophrenic patients showed impaired verbal fluency and generated a smaller number of semantic clusters than the control subjects. These findings point to a defect in self-initiation of semantic categorization in schizophrenia.

Implicit and Explicit Memory for Verbal Information Presented during Sleep

This study examined implicit memory for words presented during sleep. Ten experimental subjects were presented with word pairs including a homophone and a close associate (e.g., “tortoise-hare”) and with category-instance pairs (e.g., “bird-cardinal”) during REM or Stage 2 sleep and tested immediately afterward. Twelve control subjects underwent the same procedure while awake. Unlike the controls, subjects in the sleeping condition showed no learning effects on the implicit memory tasks. Recall and recognition were observed in a few cases, but only when presentation was immediately followed by arousal.