Toward an understanding of adult intellectual development: investigating within-individual convergence of interest and knowledge profiles.

To further our understanding of the role interests play in the development of adult intellect, this study examines the relationship between intraindividual differences in interest and knowledge profiles. On the basis of a sample of 330,154 individuals, results show a moderate, positive average intraindividual correlation between interest and knowledge that increases as individuals age and is stronger for men than for women. Consistent with recent theories regarding the development of adult intelligence, expertise, and talent, these results demonstrate that noncognitive intraindividual differences can add to one's understanding of the acquisition of knowledge and skills. The current findings regarding the intraindividual convergence of interests and knowledge substantiate K. Murphy's (1998) call for renewed research on interests and point to the usefulness of an intraindividual perspective in applied psychology.

Comparison ratings of pureed versus molded fruits: preliminary results.

Food molds change the appearance of pureed items to resemble typically prepared food. The present study examined the perceptions of 12 adults with normal swallowing and two adults with impaired swallowing for typical pureed versus molded pureed fruits (peach and pear). Results are presented for ratings of overall liking, taste, texture, appearance, and ease of chewing and swallowing. The present findings indicated that the pureed food molds did not positively influence attribute ratings. For both groups of adults, the typical method of pureed food presentation was rated higher or very similar to the molded pureed fruit. Results are discussed in terms of scaling methods, criteria applied for ratings, and implication of altering the viscosity of pureed foods.

Caffeine and light effects on nighttime melatonin and temperature levels in sleep-deprived humans.

The effects of caffeine ingestion and exposure to bright light, both separately and in combination, on salivary melatonin and tympanic temperature were assessed in humans. Four treatments during a 45.5 h sleep deprivation period were compared: Dim Light-Placebo, Dim Light-Caffeine, Bright Light-Placebo and Bright-Light Caffeine. The Dim Light-Caffeine condition (200 mg twice each night) relative to the Dim Light-Placebo condition suppressed nighttime melatonin levels and attenuated the normal decrease in temperature. Combining caffeine ingestion with bright light exposure (> or = 2000 lux) suppressed melatonin and attenuated the normal nighttime drop in temperature to a larger degree than either condition alone; i.e. effects were additive. Circadian effects were also observed in that the amplitude and phase of the temperature rhythm were altered during treatment. These findings establish that the human melatonin system is responsive to caffeine. Other evidence suggests that caffeine may influence melatonin and temperature levels through antagonism of the neuromodulator adenosine.

Exploring fantasies of TAT reliability.

It has been argued that low TAT stability estimates are an artifact of retest instructions to be original and creative. This view was supported in a recent study by Winter and Stewart (1977) who found that test-retest reliability was higher when subjects were told on the second occasion to write the same stories than when they were told to write different stories. This study attempted to replicate Winter and Stewart's results and also to determine whether the similarity of stories did vary as hypothesized. The replication was only partially successful. More importantly, it was concluded that while instructions to write similar stories did improve reliability, the increase reflected only subjects' memory capabilities and not greater stability in motive expression. While true TAT stability may still be commonly underestimated, altering retest instructions to improve reliability does not appear to be the solution.