Mechanisms of long-term dark adaptation

It has previously been suggested that long-term dark adaptation is controlled by bleaching signals that regulate the activity of an allosteric, positively cooperative protein (Stabell et al., 1986a, b). Recent biochemical evidence strongly supports this assumption, indicating that the primary regulator of the light-sensitive channels in the plasma membrane of the outer segments of the photoreceptors is a homo-oligomeric, allosteric, positively cooperative protein. In this report, we discuss the possibility that signals from bleached photopigments may control the dark-adaptation process through the allosteric protein of the plasma membrane. It is suggested that the concentrations of the bleached photopigment and of the allosteric effector are reciprocal quantities.     

Self-reported arousal Factorial complexity as a function of the subject's arousal level

Abstract.— The factorial stability of a previously constructed six-factor check-list for self-reported arousal was studied in three different situations which were conceived of as inducing different levels of arousal, viz. in the evening before going to bed, at a lecture, and at an examination. The analyses showed that the six factors obtained in the Lecture group were reduced to five in the Examination group and to four in the Evening group. This reduction was due to a combination of the items from pairs of the original factors into one factor. Significant differences between the three groups were obtained in all factors but one. The results were regarded as support for the usefulness of the six-factor instrument, the implication being that one or two of the factors in some situations might be redundant. The relevance of the results for a previously proposed model of arousal was discussed.     

Memory for the spatial layout of the everyday physical environment: Differential rates of acquisition of different types of information

The hypothesis that the relative locations of the landmarks in a town is not accurately remembered before the paths between them have been learned was refuted in the present study showing that the reverse may in fact be true. In two of the three experiments carried out, undergraduates were found to give accurate estimates of the relative directions to different landmarks in an average-sized Swedish town (Umeå with about 80 000 residents), even if the subjects had been living there no more than two to four months. However, for some reason which could not be disentangled relative distance estimates turned out to be less accurate. In the third experiment, undergraduates who had lived for two months in the town by contrast hardly remembered which places among designated ones they would pass by the most direct path, whereas those who had been one year longer in the town were much better although not perfect. Finally, no sex differences were observed and there were no important differences depending on whether memory was tested for the central area of the town or for the whole town including the outskirts.     

Active and passive avoidance performances following bilateral olfactory bulbectomy

Three experiments were performed to study the effects of bilateral olfactory bulbectomy upon active and passive avoidance conditioning. In the first experiment, olfactory bulbectomized rats were found not to be impaired on a one-way active avoidance task but showed a fear retention deficit. In Experiment 2, sham-operated rats demonstrated a degree of fear retention that was a positive linear function of the number of shock presentations; olfactory bulbectomized rats showed a total absence of fear retention. In the third experiment olfactory bulbectomized rats failed to demonstrate the inverse relationship between shock intensity and two-way avoidance performance normally evidenced. The pattern of data obtained suggests that while bulbectomized rats do not show any general avoidance impairment they do seem to be unaffected by the suppressive effects of shock upon ongoing behavior.     

Self-reported arousal during sleep deprivation and its relation to performance and physiological variables

Bohlin, G. & Kjellberg, A. Self-reported arousal during sleep deprivation and its relation to performance and physiological variables. Scand. J. Psychol., 1973, 14, 78–86.-Thayer's (1967) self-report inventory was translated and subjected to factor analysis. A four factor solution, slightly deviant from Thayer's, was adopted. The factors were labelled Sleep-Wakefulness, Stress, Euphoria, and Energy. Twenty Ss took part in a sleep deprivation (SD) experiment, which included physiological (EEG, skin conductance, body temperature), and reaction time (RT) recordings. All four factors showed decreasing trends over the night of SD, and with the exception of the Stres Factor, they were correlated with body temperature variations. The ratings in Sleep-Wakefulness and Energy were significantly lowered as a result of SD. The effect of SD upon these factors was also correlated with the effect upon the RT task and the physiological variables. From these results a model for phenomenological arousal was proposed and discussed.     

Reply to William R. Ferrell's paper "Calibration of sensory and cognitive judgments: A single model for both"

William R. Ferrell's paper is a reply to our article "Calibration of sensory and cognitive judgments: Two different accounts", 1993, 34, 135–148 in this journal. Ferrell's critique centres around three issues: (1) The model of sensory discrimination proposed by Björkman et al. (1993) and discussed in Winman and Juslin (1993) is not new, (2) this model does not predict underconfidence, (3) there is no need for separate models of calibration of sensory and cognitive judgments. Below we respond to each of the three issues raised by Ferrell.     

Environmental influences on psychological restoration

Research on psychological restoration and restorative environments is a needed complement to work on stress and environmental stressors. Two laboratory experiments tested the utility of two restorative environments theories, one concerned with directed attention capacity renewal and the other with stress reduction and associated changes in emotion. Various strategies were employed to distinguish restorative effects from other effects, to limit the role of arousal reduction in attentional restoration, and to begin mapping the time course for the emergence of outcomes. Both experiments tested for differential emotional and performance effects as a function of photographic environmental simulation (natural or urban environment). Across the experiments the natural environment simulation engendered generally more positive emotional self-reports. That consistent performance effects were not found in either study suggests that attentional restoration as reflected in performance is a more time-intensive process.     

Marble burying and spontaneous motor activity in mice: interactions over days and the effect of diazepam

Spontaneous motor activity of mice was studied in the presence or absence of 24 coloured glass marbles with and without treatment with different doses of the anxiolytic compound, diazepam. The three parameters of motor activity, locomotion, rearing and total activity, were measured in automated test cages. All the groups exposed to the marbles exhibited considerable and comparable marble burying, but there was an important interaction between marble burying and locomotor activity over test days. The "marbles" group performed fewer locomotion counts than the "no marbles" group on Day 1 but more counts on Day 3. The "marbles" group performed more rearing and less total activity than the "no marbles" group generally and this relationship was not altered over test days. Diazepam caused a dose-dependent decrease of both marble burying and the three parameters of motor activity but did not cause further increases in motor activity in the groups exposed to the marbles. These results are discussed with regard to the effects of "coping" behaviours on measures of motor activity. In conclusion, the present motor activity-marble burying test appears to be a suitable animal model for testing potential anxiolytic compounds.     

Differential effects of stress-inducing instructions on anxiety, learning and performance

Marton, F. I., Fransson, A., Jonsson, B., Klenell, A.-Ch. & Roos, B. Differential effects of stress-inducing instructions on anxiety, learning and performance. Scand. J. Psychol., 1973, 14, 213–219.-In an attempt to investigate the effects of induced stress on anxiety, learning and performance, the separate effects on the learning and performance phases were obtained by varying the timing of the introduction and the removal of stressinducing instructions. Stess-inducing instructions had a positive effect on learning but were not significantly related to the level of anxiety in the learning phase. In the performance phase the results were reversed, i.e. the stress-inducing instructions had a significantly positive effect on the level of anxiety but none on performance. The apparent paradox stemming from the significant negative relationship between anxiety and achievement within conditions could be resolved by considering the common confusion concerning statistical vs. causal relationship.