Thomas V. Petros

Horne and Ostberg questionnaire : A score distribution in a large sample of young adults

Abstract In the present study, the ‘eveningness-morningness’ dimension, as measured by the Horne and Ostberg (H&O) questionnaire, was examined in a college student population totalling over 1600 undergraduates. The majority of students were found to be evening types (62.4%), and 29.3% were neither type. Very few students were morning types (8.3%), and most of these individuals were significantly older than the students who were classified in the other two types. This is a first large-scale study showing the distribution of the H&O scores in a sample of young adult college students. Also, this study is the first report of significance found between the H&O typology (i.e. an evening and morning type) and gender. Female participants showed significantly stronger tendency toward the morningness dimension (χ2 = 7.05, P

Psychometric properties of the reduced Horne and Ostberg questionnaire

Abstract The purpose of the present study was to begin the process of establishing psychometric soundness of the reduced Horne and Ostberg questionnaire (rH&O, Adan & Almirall (1991) . Horne and Ostberg morningness–eveningness questionnaire: a reduced scale. Personality and Individual Differences, 12 , 241–253.). In the first stage of the study a total of 1882 students from the University of North Dakota were administered the original H&O questionnaire ( Horne & Ostberg (1976) . A self- assessment questionnaire to determine morningness–eveningness in human circadian rhythms. International Journal of Chronobiology, 4 , 97–110. 19-items). Five items that constitute the rH&O were extracted from the original 19 items questionnaire and the relationship between the total scores of both questionnaires, and between the circadian types determined by H&O and rH&O was measured by computing appropriate correlation coefficients. In the second stage of the study the original H&O questionnaire and the rH&O (5-items) questionnaire were administered to another group of college students ( n =150). The results from both parts of the present study indicate that the rH&O has adequate inter-item correlations as well as high coefficient alpha. Furthermore, the rH&O questionnaire is sufficiently sensitive with respect to the results of the original H&O questionnaire and it reliably classifies research participants across the “morningness–eveningness” dimension. Working with the rH&O could save both the researchers and the participants time and effort, especially if large samples of populations are to be studied. Conclusions and limitations are discussed as well as the directions for future studies.

Individual differences in the effect of time of day on long-term memory access

Individual differences in the pattern of circadian arousal on the speed of accessing information from long-term memory were investigated

Dose-dependent effects of hydrocortisone on memory in human males

Eighty male undergraduates were administered either glucose or 5, 10, 20, or 40 mg of hydrocortisone in a double-blind procedure. After 60 min they were asked to listen to eight 12 word lists and then asked to recall the words. In addition to the expected effects of rate of presentation, serial position, and practice there was a significant interaction between dose of hydrocortisone and practice. Early recall was facilitated by all doses used whereas later recall was facilitated by treatment with 40 mg and impaired by treatment with 5 mg. These findings are discussed in the context of the effects of pituitary adrenocortical hormones and memory function.

The effect of Ginkgo biloba on memory in healthy male volunteers

The purpose of this study was to investigate possible effects of Ginkgo biloba, a widely used herbal extract, on memory. This study incorporated a double-blind, placebo-controlled design, which used 30 healthy male subjects in each of two groups. The treatment group received two 60-mg tablets of BioGinkgo (27/7) [corrected] daily for 5 days, while the placebo group received a placebo. On the fifth day, after a 2-h waiting period, all subjects were given the Sternberg Memory Scanning Test [Q. J. Exp. Psychol. 27 (1975) 1.], a reaction time control test, the vocabulary and digit span subtests of the WAIS-R [Wechsler D. Manual for the Wechsler adult intelligence scale - revised. New York: Psychological Corporation, 1981.], a reading span test [J. Verbal Learn. Verbal Behav. 19 (1980) 450.] and a prose recall test [Discourse Proc. 13 (1990) 387.]. Blood pressure, heart rate and side effects were also monitored throughout the study. Nonsignificant results were found on all interactions involving treatment group on all tests except the Sternberg Memory Scanning Test. The extract appeared to be safe but largely ineffective in enhancing memory.

The effects of caffeine, impulsivity, and sex on memory for word lists

The present study examined the effects of caffeine on memory for supraspan word lists. Twelve groups of male and female college students classified as high or low impulsive received either 0, 2, or 4 mg/kg of caffeine. Female subjects were tested only during the menstrual phase of their cycle and were not taking oral contraceptives. Subjects listened to 12 word lists presented at one of four rates. Caffeine facilitated recall in females after practice with the task, but impaired recall in males only at the medium dose. The observed effects of caffeine were not influenced by subjects verbal ability, typical amount of caffeine consumption, or level of impulsivity. The results suggest that the effects of caffeine on females may vary according to the level of estrogen in the subjects system.

Effects of transdermal nicotine on prose memory and attention in smokers and nonsmokers

Previous research investigating cognitive effects of nicotine has produced mixed findings partly due to the use of abstaining smokers and cigarettes as a delivery system. The present study examined effects of nicotine delivered via a transdermal patch on prose memory and sustained attention in male smokers (n=25) and nonsmokers (n=22), who were randomly assigned to either a placebo or a nicotine condition. All groups were matched on their verbal ability and gross personality characteristics (state/trait anxiety levels, extroversion-introversion, and impulsivity level). In the nicotine condition, smokers were treated with a 21-mg transdermal patch, while nonsmokers received a 7-mg nicotine patch. Six hours following patch application, their performance was assessed on a computerized prose memory task and the Rapid Visual Information Processing task (RVIP) in a counterbalanced order and double-blind fashion. The results demonstrated that smokers in the placebo group recalled a significantly greater number of propositions than their counterparts in the nicotine group. Nonsmokers in the nicotine condition also remembered significantly more of the prose material than smokers in the same condition and showed a trend towards better recall of propositions of medium importance in the nicotine condition in comparison to the nonsmokers in the placebo group. No between-group differences were found on the RVIP task. A significant effect of time was found for systolic blood pressure and heart rate. The results cannot be interpreted using the arousal theory of nicotine effects on attention and are explained on the basis of a dose-dependent nicotinic action possibly recruiting cholinergic cortical projections.

Developmental and reading ability differences in accessing information from semantic memory

A categorical judgment task was utilized to investigate the relationships between word recognition skills and reading achievement at several grade levels. In the first experiment skilled and unskilled readers from Grades 2, 4, and 6 made cognitive decisions about pairs of words using either graphemic, lexical, or semantic information. In Experiment 2 skilled, average, and unskilled readers from Grades 1, 3, and 5 made semantic decisions about word or picture pairs. The speed and accuracy of word encoding, lexical access, and semantic memory access processes varied as a function of reading ability. These results suggest that inefficient word recognition skills can contribute to reading deficiencies as can deficiencies in semantic memory organization.

Effects of smoking on memory for prose passages

The present study examined the effects of smoking on memory for prose passages. Habitual male smokers were matched on verbal ability, impulsivity level, and habitual smoking level and were instructed to smoke either a 0.1 mg (control), a 0.7 mg, or a 1.5 mg nicotine cigarette in a controlled fashion. Immediate recall after reading expository passages was obtained. The results indicated that the subjects who smoked the 0.7 mg nicotine cigarette recalled a greater proportion of the idea units than the control group, with no difference between the 1.5 mg group and the control. In addition, blood pressure and heart rate significantly increased in all groups immediately after smoking, with heart rate increases greater in the 0.7 mg and 1.5 mg groups than the control. Interpretive hypotheses for the results include arousal theory, with optimal arousal levels being obtained in the 0.7 mg nicotine group for the prose recall task, and nicotine specific effects, including nicotines influence on the cholinergic system.

Individual differences in the influence of time of day on executive functions.

Previous research has documented the impact of time of day on vigilance and memory and the moderating influence of circadian typology (morningness-eveningness) on the relationship between time of testing and cognitive processes. This study examined the impact of circadian typology and time of testing on executive functions. Morning-type and evening-type people were randomly assigned to a morning or afternoon testing time, and their performance on neuropsychological tests, including the Conners Continuous Performance Test (CPT), the Digit Span test, the Controlled Oral Word Association Test (COWAT), and the Wisconsin Card Sorting Test (WCST) was compared. No interactions between circadian typology and time of day were observed on the CPT or Digit Span test. A time of day effect was found on the letter generation portion of the COWAT. More words were generated in the afternoon than in the morning. In contrast, performance on the WCST was best when morning-type participants were tested at their optimal time of day. These findings suggest that circadian typology should be considered when scheduling neuropsychological assessments, rehabilitation training, and critical job tasks.