DOUBLE DISSOCIATION BETWEEN MEMORY SYSTEMS UNDERLYING EXPLICIT AND IMPLICIT MEMORY IN THE HUMAN BRAIN

Abstract— Amnesic patients have impaired explicit memory that is evident in poor recall and recognition of words, yet can have intact implicit memory for words as measured by repetition priming, the enhanced efficiency for reprocessing those word's. The dissociation between explicit and implicit memory for words is a fundamental characteristic of normal cognition that could reflect two different functional architectures of the human brain two separate processing systems or two levels of operation of a single system with implicit memory less demanding of that system. We present a patient who has a lesion in the right occipital lobe and who showed intact explicit and impaired implicit memory for words. The deficit was specific to visual priming. The double dissociation between explicit and implicit visual memory for words indicates that separate processing systems mediate these two forms of memory, and that a memory system in right occipital cortex mediates implicit visual memory for words.     

Illusions of Safety in a Risky World: A Study of College Students' Condom Use

The role that costs, benefits, and perceptions of invulnerability play in condom use was examined in a sample of students ( N = 211) at 4-year and 2-year colleges. In multiple regression analyses, past condom use was related to relative invulnerability, low present risk, and inexperience. Less intended condom use was associated with high perceptions of relative invulnerability and low perceptions of present risk. It appears that many college students feel protected from HIV because they judge their current sexual environment to be safe due to monogamy, sexual history taking, and the ability to tell a partner's HIV status. Independent of that, feelings of relative invulnerability are associated with more condom use—perhaps an accurate judgment of past risky behavior.     

A relay driver and contact closure sensing interface for an LSI-11 DRV11 parallel I/O board

A simple input and output circuit is described that allows users to sense contact closures and to drive relays from a Digital Equipment Corporation LSI-11 DRV 11 parallel interface board or a signal-compatible equivalent.     

A simple LSI-11 system for real-time control,interevent time storage,and data analysis

A simple laboratory computer system based on a Digital Equipment Corporation LSI-11, floppy disk, DRV11 parallel input-output board, and the RT-11 operating system is described. Interface to experimental devices is provided through a lab-built relay driver and relay closure sensing interface. An extensive high-level software package provides an easy-to-use control language (e.g., stimuli can be controlled with a simple “TURN ON” or “TURN OFF” instruction) and easy-to-use FORTRAN subroutines for data exploration (e.g., “IFIND” searches a data file for a particular event). The control software automatically generates, codes, and stores a complete log of every input and output event and its time of occurrence in each of five simultaneously running experiments. This provides the capability to reanalyze data in light of hypotheses not available when the experiment was designed. The FORTRAN subroutine library for data exploration provides a conditional and iterative search facility to sift out events or sets of events from the data file for analysis. Standard FORTRAN statements perform arithmetic operations on the resulting data.     

A perceptual comparison: All-voiced versus typical reading passage read by children

The present investigation tested the modified vocalization hypothesis (Hutchinson and Brown, Journal of Fluency Disorders, 1978, 3, 149) in young stuttering subjects. In this study, stuttering children ages 7–13 yr were instructed to read two experimentally constructed passages. One passage contained both voiced and voiceless phonemes; the second passage was constructed using only voiced phonemes. Results indicated there was neither a quantitative nor a qualitative difference in the stuttering blocks during the reading of either experimental passage. These results would appear not to be supportive of the modified vocalization hypothesis in children; however, as has been indicative of similar studies, 8 of 22 subjects did demonstrate more dysfluencies during the reading of the passage that contained both voiced and voiceless phonemes.     

Effects of background anger,provocation, and methylphenidate on emotional arousal and aggressive responding in attention-deficit hyperactivity disordered boys with and without concurrent aggressiveness

We investigated the effects of background anger, provocation, and methylphenidate on emotional, physiological, and behavioral responding in children with attentiondeficit hyperactivity disorder (ADHD) with and without concurrent aggression. Our study revealed that ADHD boys showed more emotional and physiological distress when exposed to an interaction in which an administrator chastised each boy's favorite counselor, compared to a friendly interaction between the two adults. The background anger manipulation did not affect the aggressive behavior of the boys against an opponent in an aggressive game. High-aggressive (HA) ADHD boys were more likely to respond to provocation with aggression than low-aggressive (LA) ADHD boys, but only LA boys showed increased physiological reactivity with increasing provocation. Methylphenidate resulted in increased heart rates under all conditions and did not interact with any of the other findings.This project was conducted while the first author had the support of National Institute of Alcohol Abuse and Alcoholism grant AA 06267.The authors wish to thank the staff members of the 1987 Summer Day Treatment Program who assisted in conducting this project. The authors also express their appreciation to Karen Guthrie for coordinating the medication assessment and to Hart Blanton for computer programming.