Different patterns of cognitive slowing produced by Alzheimer's disease and normal aging

Aging has previously been shown to produce a generalized proportional slowing of all cognitive operations. In contrast, the present results suggested that Alzheimer's disease produces a disproportionate reduction in the speed with which patients carry out one or more mental operations. The tasks that demented patients found particularly difficult involved either a self-directed search of their lexicon or the use of familiarity information.     

Remarriage as a coping response for widowhood

Consideration and use of remarriage as a response to cope with the death of a husband was examined in 39 women who had been widowed and had subsequently remarried, 192 widows who had considered remarriage but had not yet remarried, and 420 widows who had not considered remarriage. Controlling for age, we found that women who had remarried reported fewer current concerns than did the other two groups. Furthermore, we found that women who retrospectively recalled the most concerns immediately after the death of the spouse were the ones who eventually remarried. The remarried group believed that they were experiencing significantly fewer concerns now than they had after the spouse's death; the women who had not considered remarriage believed that they were experiencing the same number of concerns now as before; and those women who had considered remarriage believed that they were experiencing significantly more concerns. Implications for remarriage as a coping mechanism for widowhood and the relation of age to remarriage decisions are discussed.     

Norm-of-reaction: definition and misinterpretation of animal research

The development of a phenotype is due to an interaction of the genotype with the environment. Two terms have been used to describe the outcome of this interaction, the norm-of-reaction and the reaction range. The first represents the theoretically limitless distribution of the phenotypes that may be expressed by a given genotype. The reaction range implies an upper and lower limit for phenotype expression possible from a given genotype. A critical distinction between the reaction range and the norm-of-reaction is that the norm-of-reaction is a statement of the conceivable interactions found but does not imply any predictability other than that within the conditions previously tested experimentally, that is, the tails of a normal distribution are infinitely variable, whereas the concept of reaction range implies a limitation inherent in the genotype, that is, a finite range. Empirical support for the reaction-range concept is questionable. Animal studies cited in support of the reaction range have been inappropriately and incorrectly interpreted.