Bottlenosed dolphins (Tursiops truncatus) comprehend the referent of both static and dynamic human gazing and pointing in an object-choice task

The authors tested 2 bottlenosed dolphins (Tursiops truncatus) for their understanding of human-directed gazing or pointing in a 2-alternative object-choice task. A dolphin watched a human informant either gazing at or pointing toward 1 of 2 laterally placed objects and was required to perform a previously indicated action to that object. Both static and dynamic gaze, as well as static and dynamic direct points and cross-body points, yielded errorless or nearly errorless performance. Gaze with the informant's torso obscured (only the head was shown) produced no performance decrement, but gaze with eyes only resulted in chance performance. The results revealed spontaneous understanding of human gaze accomplished through head orientation, with or without the human informant's eyes obscured, and demonstrated that gaze-directed cues were as effective as point-directed cues in the object-choice task.     

Two different biological configurations for long-term memory

Long-term memory (LTM) in Hermissenda can be distinguished from consolidated long-term memory (CLTM) by determining how long recall is retained. LTM is retained for approximately 1 day, while CLTM is retained for at least 3 days. During the transition from LTM to CLTM, the extent of retention appears to depend partially on how much consolidation has been completed. Several models are discussed that may be related to the two different manifestations of recall.     

Revealing language deficits following stroke: the cost of doing two things at once

The costs of doing two things were assessed for a group of healthy older adults and older adults who were tested at least 6 months after a stroke. A baseline language sample was compared to language samples collected while the participants were performing concurrent motor tasks or selective ignoring tasks. Whereas the healthy older adults showed few costs due to the concurrent task demands, the language samples from the stroke survivors were disrupted by the demands of doing two things at once. The dual task measures reveal long-lasting effects of strokes that were not evident when stroke survivors were assessed using standard clinical tools.     

Restraint and internal responsiveness: effects of placebo manipulations of hunger state on eating

Restrained and unrestrained subjects were given a "vitamin" (placebo) prior to an ad-lib taste test. Subjects were either told nothing about the placebo or told that previous subjects had reported that the vitamin had made them feel either hungry or full. As predicted, restrained subjects, in two separate studies, behaved in accordance with placebo messages, eating more when given "hungry" messages than when given "full" messages. Unrestrained subjects showed an apparent reverse-placebo effect; they ate less ice cream when given "hungry" information than when given "full" information. Hunger ratings did not parallel eating behavior; possible explanations for this discrepancy are considered. We conclude that unresponsiveness to internal hunger state, and an overreliance on external cognitive cues, characterizes restrained but not unrestrained individuals.     

Detection of temporal order of noise-like luminance functions

We study the capacities of human observers to time order light sources that emit dynamic noise, identical for the different light sources, except for an adjustable delay. There is a range of temporal delays for which human observers are perfectly able to perform this task, using the direction of the motion percept that is evoked by the stimulus as a cue. An optimal delay between light sources at which the observers are most robust against any deterioration of the stimulus is defined. We claim that optimal delays (15–25 msec) correspond to the time delay of a putative Reichardt correlation mechanism in human motion vision. Contrary to the ability of human observers to sense temporal correlations in noise sequences, observers are totally unable to detect anticorrelation between noise sequences. This inability rules out motion opponency as a viable model for human front-end (“early”) motion vision.     

Tic-Tac-Toe performance as a function of maturational level of retarded adolescents and nonretarded children

Two groups of retarded adolescents, differing from each other primarily in IQ (and mental age), were compared with two groups of nonretarded children, differing from each other in chronological age (and mental age), on a modified tic-tac-toe game. The mental ages of the retarded and nonretarded groups were approximately the same. It was found that the slope of performance improvement with increasing maturational level was the same for both subject groups, but the performance of the retarded adolescents was approximately 1.5 years behind mental age expectations, as derived from the performance levels of the normal children. These findings support previous suggestions of a major retardate deficit in tasks requiring logical foresight.     

Lack of acknowledgment in the family Rorschachs of families with a child at risk for schizophrenia.

Lack of acknowledgment, a characteristic of the direct interactions of families of schizophrenics, was found also to characterize the Family Rorschach interactions of families whose disturbed, non-psychotic adolescents were assessed at high risk for schizophrenia on the basis of parental communication deviance. The same high-risk families had unbalanced interaction patterns as reflected in three measures of family structure.     

Effects of expectancy and order of report on auditory asymmetries

This study examined the relation between selective attention, perception, and memory factors in the generation of auditory asymmetries. Sixty subjects were randomly assigned to one of three dichotic listening groups. One group was presented with paired linguistic stimuli, a second group with dichotic nonverbal material, while a third group heard randomly inteterspersed verbal and nonverbal pairs. Order of ear report was controlled in all three groups. Significant right ear advantages on first and second reports were found in the verbal group, and a similar pattern of left ear advantages was found in the nonverbal group. This ear by material dissociation was only found on second ear reports in the group which heard the randomly interspersed pairs. No first report ear advantages were evident in the latter group. These results are discussed in terms of the independence of perceptual and memory mechanisms in the production of auditory asymmetries.