Reflex modification in the rat: the inhibitory effects of intensity and frequency changes in steady tones

In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap.     

Stress as a state of anticipatory vigilance

The pituitary-adrenocortical system is activated in stressful situations, and the adrenocortical hormones have been implicated by Selye in the diseases of stress. Evidence indicates that the adrenocortical hormones peak during the period of anticipation of stressful events, not during actual confrontation with them. The circadian cortisol rhythm shows peaks before waking, not during active periods of the day, and cortisol does not appear to be required during physical activity. The role of these hormones appears to be to suppress ongoing physiological activity in order to increase vigilance and to get the organism ready to take action before the impact of dangers.     

The word frequency effect in lexical decision: Finding a frequency-based component

Subjects making lexical decisions are reliably faster in responding to high-frequency words than to low-frequency words. This is known as the word frequency effect. We wished to demonstrate that some portion of this effect was due to frequency differences between words rather than to other dimensions correlated with word frequency. Three groups of subjects (10 engineers, 10 nurses, and I0 law students) made lexical decisions about 720 items, half words and half nonwords, from six different categories (engineering, medical, low-frequency nontechnical, medium-frequency nontechnical, and two groups of high-frequency nontechnical). Results of two analyses of variance revealed a crossover interaction such that engineers were faster in responding to engineering words than to medical words, whereas nurses were faster in responding to medical words than to engineering words. The engineering and medical words were equally long and equally infrequent by standard word counts. We take this as support for a frequency-based component in the word frequency effect. The practical implications of this research for estimating the readability of technical text are discussed.     

Affect, personality, and facial expressive characteristics of older people

This study explored the relationship between emotion-based personality traits and expressive patterns in older subjects. Specifically, the study sought to demonstrate (a) that individuals have emotion expression biases, as revealed by structural and dynamic properties of the face, and (b) that there is a link between facial characteristics (as indexed by the judgments of trained and naive raters) and personality traits. An encoding/decoding paradigm was used; 30 adult, naive judges rated five emotion-pose photographs for each of 14 older subjects who had also completed a personality trait measure. Results indicated that individuals vary in their ability to accurately encode emotion states and that these patterns are linked to personality traits in an affect-specific way. The results are discussed within the framework of Darwinian theory and Plutchik's model of personality.     

A CROSS-CULTURAL STUDY OF PSYCHOLOGICAL DIFFERENTIATION

A cross-cultural study of psychological differentiation of Canadian and Pakistani high school students was undertaken to examine the nature of psychological differentiation in relation to differences in age/grade, gender, and academic programs. The study involved 707 Canadian students from grades 6, 8, 10, and 12; and 349 Pakistani students from grades 8, 9, 10, and 12. The Group Embedded Figures Test was employed as a measure of the field-dependence-independence cognitive style. Analyses of data included two-way and three-way analyses of variance to determine the effects of grade, gender, and academic program upon GEFT scores. Differences in psychological differentiation between high school students in the two cultures were discussed in terms of Berry's eco-cultural model.     

The width of the auditory filter in children

Because young children have poorer auditory temporal resolution than older children, they ought to have, according to the inverse relation between temporal and frequency resolution, narrower auditory filters than older children. Therefore, the auditory filters of two 6-year-olds, two 10-year-olds, and two adults were measured by having them detect a 400-ms sinusoid (500, 1000, or 3000 Hz) centered in a spectral notch in a band of noise. The signal power for 71% correct was determined as a function of notch width with the two-alternative, forced-choice procedure. The principal results showed a significant decrease in signal power with age and a significant interaction between age and notch width. The best-fitting parameters of a model of the auditory filter showed that the filter was significantly wider for the 6-year-olds than for the 10-year-olds or the adults.     

Cue depreciation: when word fragment completion is undermined by prior exposure to lesser fragments

The ability to think of a previously studied item has often been shown to be impaired when, in one way or another, the extraitem context is changed from study to test. In a series of five experiments, such impairment is induced in a somewhat different way. A fragment (e.g. r-i--rop) of a just-studied word (raindrop) is shown to be less readily completed if it is presented bit by bit (r------p, r----r-p, r-i--r-p, r-i--rop) rather than all at once (Experiments 1, 3, 4, and 5). No such effect is found if the word has not been studied beforehand (Experiments 2, 3, 4, and 5). This pattern of results occurs even when fragments of studied and nonstudied words occur in the same test and under conditions in which subjects cannot tell whether a given fragment is of a studied or nonstudied word (Experiments 4 and 5). In addition, for words that have been studied beforehand, the impairment is shown to increase systematically with the number of steps involved in the presentation of the word fragment (Experiment 3) and also to persist when the time allowed for completion of the final version of the fragment is increased from 4 s to a full minute (Experiment 5).     

The process of scapegoating in a neonatal nurses' group

This paper reviews the literature on scapegoating, elaborating on the underlying mechanisms before describing the process of scapegoating as it occurred in a neonatal nurse support group. Illustrative vignettes are used to discuss how scapegoating was used by group members to avoid painful feelings arising from their care of extremely ill infants. Group process is related to the stages of the group's development as feelings were addressed more directly and the need to use scapegoating as a defense decreased.     

Spatial attention in vision

Summary Human observers can selectively allocate processing resources to different areas of the visual field within a single fixation. This spatial attention system may affect either the quality of information extraction or the decisions and responses based on this information. This paper reviews evidence from behavioral, single-unit, and event-related potential paradigms; the evidence suggests a relatively early locus of spatial attention.This research was supported by the U. S. Army Research Office under contract DAAG 29-83-K-0049. Portions of this paper were presented to the Conference on Attention and Action, Bielefeld, West Germany, in July 1985