Hiroshi Nittono

Event-related potential correlates of individual differences in working memory capacity.

The capacity of working memory has been suggested to differ among people and these differences affect performance in a wide variety of cognitive tasks. This study explored electrophysiological correlates of individual differences in working memory capacity by means of event-related potentials. Thirty-four healthy students performed two- and five-choice reaction time tasks. In the two-choice reaction time (2CRT) task, two digits (3 and 7) were presented visually with probabilities of .20 and .80. In the five-choice reaction time (5CRT) task, five digits (3, 4, 5, 6, and 7) were presented equiprobably in a random order. Participants were required to press a button corresponding to each digit with a different finger. Working memory capacity of each participant was assessed by the reading span test originated by M. Daneman and P.A. Carpenter (1980). Participants with high reading span produced larger P300s than did persons with low reading span in the 5CRT task, but the difference was not significant in the 2CRT task. It had been suggested that individual differences in working memory capacity would affect initial stages of information processing as early as 300 ms after stimulus onset.

Background instrumental music and serial recall.

Although speech and vocal music are consistently shown to impair serial recall for visually presented items, instrumental music does not always produce a significant disruption. This study investigated the features of instrumental music that would modulate the disruption in serial recall. 24 students were presented sequences of nine digits and required to recall the digits in order of presentation. Instrumental music was played either forward or backward during the task. Forward music caused significantly more disruption than did silence, whereas the reversed music did not. Some higher-order factor may be at work in the effect of background music on serial recall.

Physiological Responses in the Concealed Information Test: A Selective Review in the Light of Recognition and Concealment∗∗This article is based partly on an article previously published in Japanese (Matsuda, 2016).

Abstract The Concealed Information Test (CIT), also called the Guilty Knowledge Test, originally was developed as a memory detection test to examine whether an examinee recognizes crime-related information that only the perpetrator knows. However, recent CIT studies have shown that the examinees intention to conceal what he or she knows also partly affects the psychophysiological responses to the information. The present chapter reviews the latest CIT studies by using an electroencephalogram, event-related brain potentials, and autonomic measures, and explains the brain activities of a perpetrator who wants to feign ignorance.

S11-3. Three points to remember when you conduct research using event-related potentials

Event-related potentials (ERP) are a part of the electroencephalogram (EEG) that is time-locked to a certain event, such as stimulus presentation or movement onset. As recent advances in electronics bring inexpensive and easy-to-use EEG amplifiers to the market, more and more people are interested in also recording ERPs. However, easy-to-use does not mean easy-to-succeed. In this talk, I will make three practical recommendations for conducting ERP research. First, make sure that the timings of events are precisely registered with the EEG data. Recent commercial EEG devices may not be as precise as traditional ones. Ask the distributor about how the device synchronizes the two information sources, and if possible, check the system yourself in terms of delays and the temporal stability of event markers. Second, try to make the whole research process as open and transparent as possible. Because brain electrical activities are multidimensional, and an infinite variety of analysis techniques are available, it is preferable to decide how to analyze the data in advance. Third, prepare to share your data with other researchers, as the “Open Science” movement is gaining popularity in this field. Institutional ethics approval and participant informed consent should be obtained to proceed in this direction.

A concealment-specific frontal negative slow wave is generated from the right prefrontal cortex in the Concealed Information Test

Recent studies have shown that a memorized item in the Concealed Information Test elicits a frontal negative slow wave (500-1000u202fms) of the event-related potential, the cortical source of which involves the right prefrontal cortex. To examine whether this negative slow wave reflects a process that is specific to concealment rather than a more general cognitive control process, we compared the event-related potentials of 24 participants in four conditions involving the presence or absence of memory and the intention to conceal. Results showed that right prefrontal activation during the frontal negative slow wave (estimated by Standardized Low Resolution Brain Electromagnetic Tomography) was only observed when participants attempted to conceal the memorized item, but not when they were motivated to reveal it or had no intention to conceal. These findings suggest that the right prefrontal cortex is involved in a concealment-specific process in the Concealed Information Test.

The light-makeup advantage in facial processing: Evidence from event-related potentials

The effects of makeup on attractiveness have been evaluated using mainly subjective measures. In this study, event-related brain potentials (ERPs) were recorded from a total of 45 Japanese women (n = 23 and n = 22 for Experiment 1 and 2, respectively) to examine the neural processing of faces with no makeup, light makeup, and heavy makeup. To have the participants look at each face carefully, an identity judgement task was used: they were asked to judge whether the two faces presented in succession were of the same person or not. The ERP waveforms in response to the first faces were analyzed. In two experiments with different stimulus probabilities, the amplitudes of N170 and vertex positive potential (VPP) were smaller for faces with light makeup than for faces with heavy makeup or no makeup. The P1 amplitude did not differ between facial types. In a subsequent rating phase, faces with light makeup were rated as more attractive than faces with heavy makeup and no makeup. The results suggest that the processing fluency of faces with light makeup is one of the reasons why light makeup is preferred to heavy makeup and no makeup in daily life.

High-Resolution Audio with Inaudible High-Frequency Components Induces a Relaxed Attentional State without Conscious Awareness

High-resolution audio has a higher sampling frequency and a greater bit depth than conventional low-resolution audio such as compact disks. The higher sampling frequency enables inaudible sound components (above 20 kHz) that are cut off in low-resolution audio to be reproduced. Previous studies of high-resolution audio have mainly focused on the effect of such high-frequency components. It is known that alpha-band power in a human electroencephalogram (EEG) is larger when the inaudible high-frequency components are present than when they are absent. Traditionally, alpha-band EEG activity has been associated with arousal level. However, no previous studies have explored whether sound sources with high-frequency components affect the arousal level of listeners. The present study examined this possibility by having 22 participants listen to two types of a 400-s musical excerpt of French Suite No. 5 by J. S. Bach (on cembalo, 24-bit quantization, 192 kHz A/D sampling), with or without inaudible high-frequency components, while performing a visual vigilance task. High-alpha (10.5–13 Hz) and low-beta (13–20 Hz) EEG powers were larger for the excerpt with high-frequency components than for the excerpt without them. Reaction times and error rates did not change during the task and were not different between the excerpts. The amplitude of the P3 component elicited by target stimuli in the vigilance task increased in the second half of the listening period for the excerpt with high-frequency components, whereas no such P3 amplitude change was observed for the other excerpt without them. The participants did not distinguish between these excerpts in terms of sound quality. Only a subjective rating of inactive pleasantness after listening was higher for the excerpt with high-frequency components than for the other excerpt. The present study shows that high-resolution audio that retains high-frequency components has an advantage over similar and indistinguishable digital sound sources in which such components are artificially cut off, suggesting that high-resolution audio with inaudible high-frequency components induces a relaxed attentional state without conscious awareness.

PERSONALITY NEEDS AND SHORT-TERM MEMORY '

This study examined a possible relationship between personality needs and short-term memory. 102 Japanese college students were administered a Japanese version of the Edwards Personal Preference Schedule and performed 3 verbal short-term memory tests. No reliable correlations were found between memory performance and the scores on the 15 scales of Edwards schedule. In contrast, course examination scores in introductory psychology were statistically significantly correlated with some scale scores. These results suggested that motivational personality traits would not be related to short-term memory performance, although they were associated with academic achievement.