Creating new memories that are quickly accessed and confidently held

In two experiments involving a total of 542 subjects, a series of slides depicting a burglary was shown. After the initial event, subjects were exposed to one or more narratives about the event that contained some misinformation or neutral information about four critical details. Finally, subjects were tested on their memories of what they saw, and their reaction times and confidence levels were measured. When subjects took a standard test in which the misinformation item was a possible response option, they responded very quickly and confidently when making this incorrect choice. Misled subjects responded as quickly and confidently to these "unreal" memories as they did to their genuine memories. It does not seem, then, that the misinformation effect arises from a large proportion of subjects who must resolve a conflict between two memories when they are tested, a conflict that would be expected to take time. When subjects took a modified test in which the misinformation item was not a possible response, misled subjects were as accurate as were controls, but they responded more slowly, regardless of whether they ultimately chose the right or wrong option. These findings indicate that misinformation does introduce some form of interference not detected by a simple test of accuracy.     

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.     

Impact of diagnosed depression and self-reported mood on mothers' control strategies: a longitudinal study

Control strategies of 70 well and depressed mothers were assessed twice: when their children were of toddler age (Time 1) and, for 39 of the mothers, when their children were 5 (Time 2). At Time 1 well mothers were more direct with their children, using more direct commands and reprimands, and fewer explanations than depressed mothers. At Time 2 well mothers used fewer direct commands than depressed mothers. Self-reported negative mood preceding the interaction in well mothers was associated with decreased directness at Time 1 but increased directness at Time 2. At Time 1 depressed mothers' negative mood was associated with a decrease in the use of explanations. All mothers used more unclear commands and fewer reprimands and positive incentives with their 5-year-olds than when the children were toddlers. Depressed mothers, but not well mothers, increased their use of direct commands when the children were older. The findings are interpreted in the context of complex interplay between mother's diagnosis of depression, self-reported mood preceding the interaction, and the developmental level of the child.     

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.     

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.