Cognition and metacognition at extreme altitudes on Mount Everest

The FACTRETRIEVAL2 test battery, which assesses both retrieval of general information from memory and metacognition about that retrieval, was administered to people before and after a recent expedition to Mount Everest and at extreme altitudes above 6,400 m (higher than any mountain in North America or Europe). The major findings were as follows: First, the same extreme altitudes already known to impair learning did not affect either accuracy or latency of retrieval, and this robustness of retrieval occurred for both recall and forced-choice recognition. Second, extreme altitude did affect metacognition: The climbers showed a decline in their feeling of knowing both while at extreme altitude and after returning to Kathmandu (i.e., both an effect and an aftereffect of extreme altitude). Third, extreme altitude had different effects than alcohol intoxication (previously assessed by Nelson. McSpadden, Fromme, & Marlatt, 1986). Alcohol intoxication affected retrieval without affecting metacognition, whereas extreme altitude affected metacognition without affecting retrieval; this different pattern for extreme altitude versus alcohol intoxication implies that (a) hypoxia does not always yield the same outcome as alcohol intoxication and (b) neither retrieval nor metacognition is strictly more sensitive than the other for detecting changes in independent variables.     

Predicate-argument structure as a link between linguistic and nonlinguistic representations

We present a study wherein a severe Broca's aphasic patient was trained to learn symbols representing both pure transitive and dative predicates--predicates differing in argument structure--in a visually based artificial language (c-ViC). We found a decrease in performance when two symbols, rather than one, were used to depict these "verbs." However, this decrease in performance was more pronounced for symbols representing pure transitive verbs--those that allow only one argument structure--than for symbols representing dative verbs--those that allow two different argument structures. Also, dative "verbs" yielded better performance when they were inserted in more complex, three-argument "sentences" than when they were inserted in two-argument "sentences." The opposite pattern was found for pure transitives. These results are discussed in terms of our claim that argument structure serves as a point of connection between linguistic information and non-linguistic visual information and in terms of the possibility that argument structure entries are shaped by the form in which visual information is parsed.     

How to study the kinetic depth effect experimentally

Sperling, Landy, Dosher, and Perkins (1989) proposed an objective 3D shape identification task with 2D artifactual cues removed and with full feedback (FB) to the subjects to measure KDE and to circumvent algorithmically equivalent KDE-alternative computations and artifactual non-KDE processing. (1) The 2D velocity flow-field was necessary and sufficient for true KDE. (2) Only the first-order (Fourier-based) perceptual motion system could solve our task because the second-order (rectifying) system could not simultaneously process more than two locations. (3) To ensure first-order motion processing, KDE tasks must require simultaneous processing at more than two locations. (4) Practice with FB is essential to measure ultimate capacity (aptitude) and, thereby, to enable comparisons with ideal observers. Experiments without FB measure ecological achievement--the ability of subjects to extrapolate their past experience to the current stimuli.     

Ethanol-mediated taste aversions and state-dependency in preweanling (16-day-old) rats

Requirements for conditioning of an ethanol-mediated taste aversion in 16-day-old rat pups were examined. Experiment 1 demonstrated that preweanling rats are capable of acquiring, in two trials, an aversion to a 15% sucrose solution when followed by intragastric intubation of a 1.2 g/kg dose of 17% v/v ethanol, but not when followed by a 0.4 g/kg dose. Comparison was with control animals given sucrose followed by an equivalent volume isocaloric Half and Half. When the 0.4 g/kg dose of ethanol preceded sucrose presentation by 30 min (Experiment 2), the aversion was learned, suggesting that the effective delay between the sucrose and the critical consequences of the ethanol had been too long with the former procedure. Expression of the sucrose aversion required, however, the reinstatement of the context of intoxication--state-dependent retention. Finally, the results of Experiment 3B indicated that, in addition to the association between the sucrose and the aversive consequences of alcohol intoxication, the orosensory cues resulting from alcohol's direct elimination, via such processes as respiration and salivation, became associated with the appetitive properties of the sucrose. This was evidenced by a conditioned increase in preference for ethanol odor. Possible age-related differences in the ability to associate stimuli with alcohol's unconditioned consequences, and in state dependency are discussed.     

Selfish genes vs. selfish people: Sociobiology as origin myth

The sociobiological version of human evolution is criticized as excessively reductionistic and focused on reproductive competition. An alternative version of evolutionary psychology is proposed based on the premise that the most important feature of human evolutionary history is selection for small group living. The structural requirements of group survival can account for fundamentally social motives characteristic of the human species such as cooperation, conformity, and group loyalty.Adapted from a symposium presentation at the annual meeting of the Society for Experimental Social Psychology, October 13, 1990, Buffalo, New York.     

Rule abstraction, item memory, and chunking in rat serial-pattern tracking

Two studies used a stimulus tracking paradigm to test whether rats are sensitive to the rule-based formal properties of structured serial patterns. Hooded rats tracked 16-element patterns of flashing lights by pressing levers under an array of 6 indicator lights. In Experiment 1, rats tracked a pattern similar to one previously used with human subjects and yielded remarkably similar results. More errors and response omissions occurred at boundaries of structural "chunks" than within chunks, and errors often reflected anticipation of the next chunk or extrapolation of the preceding chunk. In Experiment 2, temporal "phrasing" cues encouraged different groups to encode a pattern as a series of either "runs" or "trills." Differential placement of pauses induced rats to encode different rule-based representations of the pattern. Results indicate that under appropriate conditions rats may encode a representation of formal structure when they learn organized response patterns.     

Women and AIDS

While the origin of the AIDS virus remains controversial, it is indisputable that AIDS is spreading worldwide. By June 1987, the World Health Organization estimated that 50 million Africans were infected with HIV and that the disease was epidemic in many parts of the continent. However, African governments chose to deny the threat of the disease. The AIDS crisis has diverted resources from other vital areas of disease prevention, health promotion, and research. Whereas AIDS is spread in developed nations by sexual promiscuity, by drug addicts sharing unclean hypodermic needles, and by homosexual behavior, in Africa cultural factors contribute to the transmission of AIDS. Female genital mutilation leads to extensive laceration of the female genitals upon initiation of sexual intercourse and/or to substitution of anal sex during the weeks and months before vaginal penetration can be achieved. In addition, the reuse of the same knives during the mutilation can spread HIV infection. Other factors that contribute to the spread of HIV in Africa include the patriarchal practice of polygamy, the subordinate position of women that makes them unable to insist on protection during intercourse, and a failure to screen blood used in transfusions. With all of these risk factors at play, women at the grassroots level must be equipped with the health education that is the only available tool to fight AIDS. Women's organizations can provide information and education to people at risk of acquiring HIV, counsel infected persons, ensure the safety of the blood supply, and work to overcome harmful traditional practices.     

Performance objectives in the stance phase of human pathological walking

Permanent disruption of aspects of a highly learned skill such as walking force adaptations to occur to the movement. Firstly the body must determine what factors will guide the formation of the new walking pattern, and secondly that new movement pattern must be learned. Frequently the questionable assumption is made that the performance objectives of the new skill are the same as the original. This work used non-linear optimal control and multiple segment simulation to evaluate the ability of several possible objective functions to predict pathological walking patterns. These predictions were then also compared to the results from normal walking. Preliminary results indicate the performance objectives of pathological gaits may be quite different from those of normals. Some support was also provided for the existence of simultaneous multiple performance objectives in complex movements.     

Risk perceptions and participation in colorectal cancer screening

Compared individuals at high versus average risk for colorectal cancer (CRC) with respect to factors they cited as affecting their risk of developing CRC. We also examined the relationship of these risk-factor perceptions to perceived susceptibility and participation in a CRC screening test. All individuals in the high-risk group were informed that, as a sibling of someone with CRC, they were more likely to get this cancer themselves. We found minimal differences among siblings with respect to perceived susceptibility. Further, although high-risk siblings were more likely to participate in screening, only 20.2% cited heredity as a risk-increasing factor, and, among these siblings, there was no relationship between screening participation and the citation of any specific risk factors, including heredity. These findings demonstrate the need for more research examining how high-risk individuals process risk-relevant information and the effect of this information on health behavior.