Linguistic encoding in short-term memory as a function of stimulus type

In this study, we investigated bases for encoding linguistic stimuli in short-term memory. Past research has provided evidence for both phonological (sound-based) and cherological (sign-based) encoding, the former typically found with hearing subjects and the latter with deaf users of sign language. In the present experiment, encoding capabilities were delineated from encoding preferences, using 58 subjects comprising six groups differing in hearing ability and linguistic experience. Phonologically related, cherologically related, and control lists were presented orally, manually, or through both modalities simultaneously. Recall performance indicated that individuals encode flexibly, the code actually used being biased by incoming stimulus characteristics. Subjects with both sign and speech experience recalled simultaneous presentations better than ones presented orally or manually alone, which reveals the occurrence of enhanced encoding as a function of linguistic experience. Total linguistic experience appeared to determine recall accuracy following different types of encoding, rather than determining the encoding basis used.     

Telescoping is not time compression: A model

A model of telescoping is proposed that assumes no systematic errors in dating. Rather, the overestimation of recent occurrences of events is based on the combination of three factors: (1) Retention is greater for recent events; (2) errors in dating, though unbiased, increase linearly with the time since the dated event; and (3) intrusions often occur from events outside the period being asked about, but such intrusions do not come from events that have not yet occurred. In Experiment 1, we found that recall for colloquia fell markedly over a 2-year interval, the magnitude of errors in psychologists' dating of the colloquia increased at a rate of .4 days per day of delay, and the direction of the dating error was toward the middle of the interval. In Experiment 2, the model used the retention function and dating errors from the first study to predict the distribution of the actual dates of colloquia recalled as being within a 5-month period. In Experiment 3, the findings of the first study were replicated with colloquia given by, instead of for, the subjects.     

The Children's Firesetting Interview with psychiatrically referred and nonreferred children

This study evaluated the Children's Firesetting Interview (CFI). The measure was developed to operationalize multiple domains of functioning derived from a riskfactor model of firesetting. The model poses that child, parent, and family characteristics promote firesetting and continuation of a pattern of firesetting. Major factors include curiosity about fire, involvement in and exposure to firerelated activities, and knowledge about first safety The CFI, consisting of 46 questions reflecting six a prioridimensions, was administered to 519 children (ages 6–13) recruited from nonpatient, outpatient, and inpatient samples. Internal consistency and testretest reliability of the measure were satisfactory. Criterion validity was supported by the findings that firesetters showed greater curiosity about fire, involvement in firerelated activities, exposure to models/materials, and knowledge about things that burn than did nonfiresetters. These findings did not vary as a function of the child's patient status or level of antisocial behavior. Implications for the evaluation of firesetting risk are discussed.This study was supported by grant MH-39976 from the Antisocial and Violent Behavior Branch of the National Institute of Mental Health and by a Research Scientist Development Award (MH00353) from the National Institute of Mental Health. The authors acknowledge the constructive suggestions of two anonymous reviewers.     

Ratings of kinetic depth in multidot displays

Subjects saw kinetic depth displays whose shape (sphere or cylinder) was defined by luminous dots distributed randomly on the surface or in the volume of the object. Subjects rated perceived 3-D depth, rigidity, and coherence. Despite individual differences, all 3 ratings increased with the number of dots. Dots in the volume yielded ratings equal to or greater than surface dots. Each rating varied with 3 of 4 factors (shape, distribution, numerosity, and perspective), but the ratings either between trials or between conditions were often uncorrelated. Object shape affected rigidity but not depth ratings. Veridically perceived polar displays had slightly lower rigidity but higher depth ratings than parallel projection displays. (Reversed polar displays were always grossly nonrigid.) The interaction of ratings and stimulus parameters requires theories and experiments in which different KDE ratings are not treated interchangeably.     

Hefting for a maximum distance throw: a smart perceptual mechanism

Objects for throwing to a maximum distance were selected by hefting objects varying in size and weight. Preferred weights increased with size reproducing size-weight illusion scaling between weight and volume. In maximum distance throws, preferred objects were thrown the farthest. Throwing was related to hefting as a smart perceptual mechanism. Two strategies for conveying high kinetic energy to projectiles were investigated by studying the kinematics of hefting light, preferred, and heavy objects. Changes in tendon lengths occurring when objects of varying size were grasped corresponded to changes in stiffness at the wrist. Hefting with preferred objects produced an invariant phase between the wrist and elbow. This result corresponded to an optimal relation at peak kinetic energy for the hefting. A paradigm for the study of perceptual properties was compared to size-weight illusion methodology.     

Identifying depression in children: A comparison of alternative selection criteria

This study evaluated commonly used methods of identifying depressed children and examined the extent to which the conclusions about correlates of dysfunction vary among different selection criteria. Child psychiatric patients (N=237,ages 7–12) and their parents participated and completed measures to permit identification of depressed children on the basis of three separate criteria, including selfreport scores on the Children's Depression Inventory, parent-reported scores for the same measure, and a DSM-III diagnosis of major depression. The study examined whether depressed and nondepressed children, defined separately by the different criteria, differed in a variety of depression-related symptoms, cognitive processes, and social activity. The results indicated little overlap in the persons identified as depressed on the basis of child-or parent-completed CDI scores or DSM-III diagnosis. Depressed and nondepressed children tended to differ across all domains (depression-related symptoms, cognitive processes, and social activity) for each selection criterion. However, significant differences were evident in these domains only when the selection criterion and other domains were assessed with the same informant (e.g., self-report) and hence shared a common method (rater) component. The findings underscore the potential influence that method factors may have in influencing the conclusions that are drawn regarding the correlates of childhood depression.Completion of this research was supported by a Research Scientist Development Award (MH00353) and by a grant (MH35408) from the National Institute of Mental Health. The author is grateful to Debra Bass, Antoinette Rodgers, and Todd Siegel for assistance with this project.     

Regional cerebral blood flow for singers and nonsingers while speaking, singing, and humming a rote passage

Two groups of singers (n = 12,13) and a group of nonsingers (n = 12) each produced the national anthem by (1) speaking and (2) singing the words and by (3) humming the melody. Regional cerebral blood flow (rCBF) was measured at rest and during each phonation task from seven areas in each hemisphere by the 133Xe-inhalation method. Intrahemisphere, interhemisphere, and global rCBF were generally similar across phonation tasks and did not yield appreciable differences among the nonsingers and the singers.     

Reading long words embedded in sentences: informativeness of word halves affects eye movements

The possibility was explored that the informativeness of a specific region within a word can influence eye movements during reading. In Experiment 1, words containing identifying information either toward the beginning or toward the end were displayed asymmetrically around the point of fixation so that the reader was initially presented with either the informative or noninformative zone. Words were read with shorter summed initial fixation time when the reading was started from the informative zone. In Experiments 2 and 3, the target words were presented in sentences that were to be comprehended. More attention was given to the informative endings of words than to redundant endings. The latter were also skipped more often. The duration of the first fixation was not affected by information distribution within the word, whereas the second fixation duration was. The results of these experiments lend good support to the hypothesis of immediate lexical control over fixation behavior and to the notion of a convenient viewing position.     

Response to commentaries on “A neurobiological model for near-death experiences”

This work has received financial support from FONDECYT (Project 1111-88). The authors also acknowledge the helpful comments of Dr. Bruce Cassels.     

The dependence of lexical relatedness effects on syntactic connectedness

Context effects on lexical decision were analyzed by manipulating lexical relatedness and syntactic connectedness. Related and unrelated word pairs were embedded in syntactic (e.g., "the author of this book/floor") and in scrambled (e.g., "the author the and book/floor") phrases. The sequences were presented serially and subjects made lexical decisions to the terminal targets. In four experiments, relatedness effects were substantial in syntactic phrases but only marginal in scrambled sequences. This result was unaffected by presentation rate or by blocking manipulations. A fifth experiment showed that the relatedness effect in syntactic phrases involved both facilitation of responses to related words and inhibition of responses to unrelated words. These results argue against a role for intralexical priming in on-line reading. They highlight the role of syntactic connectedness and suggest that contextual facilitation depends on the ease of integration of new words with the current text-level representation.