Streaming vs. fusion of sinusoidal components of complex tones

The present experiments looked at the effect of a number of variables on the tendency of an element of a complex tone to either fuse with the other elements of the tone or be “pulled out” into a “horizontal,” temporal stream. It was found that such factors as the intensity relationship of the elements of the complex tone, the frequency of the tone being pulled out, and various factors producing temporal asynchronies between elements of the complex, all affect the tendency for either fusion or streaming to occur.     

Semantic memory retrieval: Analysis by speed accuracy tradeoff functions

Semantic memory retrieval for verifying category--example associations was tested by a speed accuracy tradeoff method: present the category for 2 s, present a correct or incorrect example followed, after a variable lag (0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1, 2, or 3 s), by a signal to make a “yes-no” response in about 0.2 s. Although the strength of the category--example association is higher for high dominance examples of a category, retrieval dynamics did not vary with dominance level. Recognition for category--example associations appears to be a direct-access (parallel) retrieval process. Priming a category by repeated testing of the same category over three consecutive trials had no effect on either asymptotic strength or retrieval dynamics. Partitioning into short, medium, and long latency responses at each lag produced microtradeoff functions which did not lie on the same macrotradeoff function. Retrieval dynamics were invariant with long-term practice.     

Aphasia type and aging

We analyzed the relationship between age and clinical type of aphasia in 167 right-handed men who had suffered cerebrovascular accidents. Patients with unequivocal diagnoses as Broca's, Wernicke's, anomic, conduction, and global aphasics were considered. The median age of the Broca's group (51 years old) was significantly lower than that of the total group (55.8 years old), while the median age of the Wernicke's group was significantly higher (63 years old). Moreover the incidence of Wernicke's aphasia increased steadily with age, while incidence of the other types of aphasia peaked in the sixth decade and then diminished with increasing age.     

Shift of visual field preference for English words in native Hebrew speakers.

Lateralization for visual verbal material was tested with Hebrew and English stimuli presented to Israeli adolescents in their second, fourth, and sixth years of study of English as a second language. Seventy-two children, 12 male and 12 female subjects in each class, were tested by means of a target-word recognition task. Laterality scores derived from reaction-time measures resulted in: (1) a left visual field preference for the English stimuli in the youngest group which decreased with increasing age, becoming a right visual field preference in the oldest group, and (2) a significant and equal right visual field preference for Hebrew stimuli for all groups. The data suggest right hemisphere involvement in acquiring the reading skills of a new language.     

A prospective naturalistic study of the impact of an intensive medical treatment on the social behavior of child and adolescent cancer patients

The impact of intensive chemotherapy and prolonged hospitalization on the social behavior of child and adolescent cancer patients was assessed. Twenty-three patients, aged 18 months to 21 years, were observed while they received chemotherapy in a protected environment or in a regular hospital room. Single-subject analyses were used to examine changes on six behaviors in relation to changes in physiological status. Fourteen patients showed significant change in the frequency of at least one behavior. Play and sleep were the behaviors most likely to change. The changes began to occur as patients experienced the systemic toxic effects of the drugs, although a dissipation of drug toxicity generally was not accompanied by a corresponding behavior change. The findings are discussed in relation to age-developmental and interindividual heterogeneity in response to treatment.     

Analogue drinking assessment: Sensation seeking and gender

This study assessed the relationship between sensation seeking measured as a trait variable and drinking behaviors observed unobtrusively in the laboratory. It was hypothesized that high-sensation-seeking subjects would consume more alcohol than low sensation seekers and experience greater enhancement of positive moods and body sensations associated with intoxication. Thirty female and 31 male subjects divided into high- and low-sensation-seeking subgroups participated in an ad libitum drinking situation with the manifest task of taste rating three types of vodka (actually 95% alcohol) or tonic. Dependent variables included beverage consumption, positive/negative mood states, body sensations, breath estimates of blood alcohol levels, and self-rated level of intoxication. All subjects reported feeling the effects of alcohol. Contrary to predictions, high-sensation-seeking subjects neither consumed more alcohol than their low-sensation-seeking counterparts nor drank more alcohol than tonic, Paradoxically, low-sensation-seeking women displayed significantly greater alcohol intake and intoxication than all other groups. Possible explanations for findings were considered as well as the necessity for multimethod assessments of both predictor (i.e., sensation seeking) and criterion (i.e., alcohol consumption) variables across time and situations.This research was supported by Grant Award AA04042-03 from the National Institute on Alcohol Abuse and Alcoholism to the first and third authors. Special Appreciation is expressed to Anne T. Patsiokas, Susan W. Altman, Victoria Molony-Sinnott, and Pamela J. Thompson for their invaluable assistance in collecting and analyzing the data.     

Development of sensitivity to information for impending collision

Infants were tested in three experiments to study the development of sensitivity to information for impending collision and to investigate the hypothesis that postural changes of very young infants in response to an approaching object are of a tracking rather than of a defensive nature. Experiment 1 involved the presentation of three types of shadow projection displays, specifying (1) collision, (2) noncollision, and (3) a nonexpanding rising contour, to infants from 1 to 9 months of age. Avoidance of collision appears to be absent in 1- to 2-month-olds, begins to develop in 4- to 6-month-olds, and is present in 8- to 9-month-old infants. In Experiment 2, 1- to 2-month-old infants were presented with optical expansion patterns which specified collision and noncollision. The top contour of these displays stayed at eye level. No significant difference was observed between reaction to the collision and the noncollision displays, suggesting that the young infants were tracking the displays and not attempting to avoid collision. Experiment 3 was designed to determine whether an approaching real object might elicit an avoidance response in infants not sensitive to an optical display specifying collision. No evidence of avoidance behavior was observed in the 1- to 2-month-olds; however, avoidance, as indexed by blinking, does appear to be present at 4 months of age.