The Declining course of recognition memory

Recognition memory for words can decline, sometimes precipitously, over the course of the recognition test. Decrements of as much as 75% in d’ have been observed from the first quarter of testing to the last. and decrements of 40%–50% are not uncommon. Proactive mechanisms, imperfectly understood, appear to underlie such declines: Processing early input renders late input less recognizable, and making early recognition judgments renders later judgments more difficult. At the same time, the processing of late-input words fails to inhibit the recognition of the words that preceded them.     

An inexpensive circuit for beta,alpha, theta,or delta EEG biofeedback

An inexpensive circuit is described for EEG biofeedback or measurement. The circuit is designed to interface easily with most basic EEG machines. It taps the output from a single recording channel of the basic EEG instrument and provides the following for each EEG band (beta, alpha, theta, and delta): (a) very selective bandpass discrimination, (b) variable center frequency, (c) variable threshold at which feedback will be provided, or the measurement made, and (d) use with any biofeedback stimulus or measurement device that one wishes to switch contingent with S’s EEG rhythms.     

Inter-digital variability in the palmer sweat indices of adult stutterers

This study examined the relationship of mean palmar sweat density of all fingers of each hand, thumbs excluded, to asymetrical interdigital sweat variability in adult stutterers. In addition, the relationship of mean print density to part word repetitions and prolongations was investigated.

A modification of the palmar sweat printer developed by Brutten (1957) enabling the accommodation of eight fingers, was employed to obtain simultaneous PSI under identical controlled conditions for all fingers.

Results indicated that the eight fingers are not reliable areas for the determination of palmar sweating in adult stutterers. Consequently, the PSI as it is currently employed, as well as the method used in the present study, does not appear to be an acceptable objective measure of ANS arousal in adult stutterers.     

The effect of meaningfulness in tachistoscopic word perception

Studies of tachistoscopic word perception were reviewed under two theoretical headings: the structural approach, in which the variables of interest are linguistic relations among letters, and the lexical approach, where the interest is in the availability of words in lexical memory. The results of a recent tachistoscopic recognition study question the importance of lexical availability by finding no difference in performance between meaningful words and well-structured, pronounceable nonwords. In the present study, further comparisons between words and pronounceable nonwords were performed, and a meaningfulness effect was demonstrated. The generality of this finding was discussed, and alternative models accounting for the effect were considered. Two of these were capable of explaining structural effects as well as the meaningfulness effect: a translation model and a lexical discrimination net.