The unimportance of being random

This note fleshes in and generalizes an argument suggested by W. Salmon to the effect that the addition of a requirement of mathematical randomness to his requirement of physical homogeneity is unimportant for his ontic account of objective homogeneity. I consider an argument from measure theory as a plausible justification of Salmon's skepticism concerning the possibility that a physically homogeneous sequence might nonetheless be recursive and show that this argument does not succeed. However, I state a principle (the Generalized Salmon Thesis) that is intuitively plausible and reflects this skepticism. The principle entails that one should be just as certain that the limit of such an infinite sequence is irrational as one is certain that the sequence is not computable. But I claim that this consequence is acceptable.     

Priming semantic relations in patients with Huntington's disease

To investigate the hypothesis that Huntington's Disease involves a breakdown in the organization of the lexico-semantic representational system, mildly and moderately demented patients with Huntington's Disease and age-matched normal control subjects were given a brief battery of language tests and a semantic priming free association task. Results of the language tests provided suggestive, but confounded, evidence for a semantic deficit in Huntington's Disease. Less equivocal evidence was yielded by results of the priming task, which showed a decline in the effect of association strength of primed stimulus-target word pairs on target hit rates. This finding was interpreted as a disruption in the system of spreading activation in a lexico-semantic network. This breakdown was contrasted with the more severe language deficits found in dementias which are primarily cortical in origin.     

Comments on 'Call for a follow-up study of experiments on long-term deprivation of human infants' by Micha Razel

Razel's examination of the early work of McGraw and the Dennises puts a heavy requirement on studies of single subjects and on some possible interpretations for which, unfortunately, documentation is insufficient. Further, the Dennises placed more emphasis on the autotelic quality of motor mastery than Razel notes. Rather than looking for these persons whose behavior was studied long ago, direct study of motor mastery by systematic provision of enrichment conditions during early development is more likely to be instructive and a better use of scientific resources.     

Recall of autobiographical events

The clarity with which events that happened 6 years earlier can be recalled was estimated. The estimates are consistent with a gradual degradation rather than a precipitate decline of memory, and with the proposition that once an event cannot be recalled then it will remain inaccessible under similar conditions of cueing. Rare events are recalled well, suggesting that proactive interference has a strong influence on difficulty to recall. Vivid events are recalled well, also, but other dimensions such as importance of the event, its association with semantic knowledge, and the intensity of physical sensation are not related to recallability. Memory for the date of an event is poor, but for its time of day is good.     

AIDS and intimate relationships: Adolescents’ knowledge and attitudes

The knowledge level about HIV/AIDS among American adolescents aged 16 to 19 has been assessed on several occasions, showing that in recent years their knowledge base has improved. The knowledge bases of British adolescents and of adolescents younger than 16 have been largely ignored. In attempting to assess the likely impact on present or future behaviors of increasing adolescents’ knowledge base about AIDS it is important to also know something of adolescents’ attitudes to intimate relationships and to sex within those relationships. Previous studies have not linked these two aspects. In this study two hundred London schoolchildren aged 14 and 15 years completed a questionnaire tapping both their knowledge about HIV infection and its transmission and their attitudes to intimate relationships. Their answers revealed that they had absorbed the simple media messages about AIDS, that it kills and that use of a condom during sex offers protection. However they were less well informed on detailed aspects of prevention, although, worryingly, they believed that they knew all that they needed to about preventive measures. The majority had attitudes to intimate relationships that were compatible with the message of restricting their number of sexual partners; however, a significant minority did not. The latter were more likely to deny the risk associated with promiscuity. It is suggested that school-based AIDS education programs should help individuals to develop new attitudes to intimate relationships that are compatible with risk avoidance.     

Age and sex as factors influencing spontaneous exploration and object investigation by preadult rats (Rattus norvegicus).

This study examined developmental and sex differences in the exploratory and investigatory behaviors of Long-Evans rats (Rattus norvegicus). Littermate sextuplets were divided into sex-matched groups (at 30, 60, and 90 days of age) and were individually videotaped on 2 consecutive nights in an arena that contained stimulus objects. Multiple measures of locomotor exploration and object investigation increased significantly with age but were not influenced by sex. Older rats entered more quickly, were more active, spent more time in the arena, and spent more time investigating inanimate stimulus objects than did younger rats. Sex did not significantly affect most measures of open-field behavior; however, the data suggest that the sexes may begin to diverge by 90 days. These results suggest that preadult rats of both sexes are equipped early in development with similar strategies and repertoires for exploration and investigation.