Algis Ivinskis

A Study of validity of open-field measures

Abstract Seven open-field measures (defecation, ambulation, urination, washing, rearing, latency and inner circle activity) were obtained using a number of different scoring methods for albino and hooded rats. The validity of these measures was examined using (a) day by day decrease of open-field behaviour, (b) effects of retesting over a period of time, (c) variation of stimulus intensity (light and noise). It was found that methods a and b did not provide satisfactory validity estimates. Method c indicated that defecation and latency can be accepted as valid indices of emotionality in rats.

The reliability of behavioural measures obtained in the open-field

Abstract Seven open-field measures (defecation, urination, ambulation, washing, rearing, latency, and inner circle activity) were obtained using a number of different scoring methods for albino and hooded rats. The albino Ss were tested on 3 different occasions. The first test session was conducted when Ss were 90 days old, the second test session was held 63 days later and a third test session was conducted 154 days after the second. The hooded rats were subjected to 1 test session when Ss were 90 days old. The reliability of these measures was examined using test-retest and odd-even day correlations. The obtained results suggested that defecation, ambulation and rearing can be considered as providing reliable measures of behaviour in the open-field.

A note on the open‐field test of emotionality

Abstract The open-field test of emotionality and related methodological problems were investigated. Ss were exposed to two physical stimuli presented simultaneously in the open-field enclosure for two minutes each day. Two series of 4 days each (with a time interval of 90 days between series) were conducted. Four behavioural measures were obtained under these conditions, defecation, urination, ambulation and washing. The interrelationships and the reliability of these measures were examined.

Detection of Moving Stimuli in the Binocular and Nasal Visual Fields by Infants Three and Four Months Old

A technique of monocular eye patching was used to measure the response of infants three and four months old to nasally and temporally placed stimuli at various eccentricities in the visual field. The results indicated a field of binocular overlap of approximately 60 deg in infants three months old and 80 deg in infants four months old. These figures compare with visual field widths obtained under binocular viewing conditions of at least 140 deg in infants three months old and of at least 150 deg in infants four months old.

Prenatal psychological stress effects on offspring behaviour in rats

Prenatal stress experienced by the mother usually results in behavioural changes in the offspring. The first part of this study is concerned with the mothers, who were either psychologically stressed or were subjected to a control procedure, during pregnancy. At weaning one-half of each group of mothers was used to establish the glucocorticosterone levels (11-OHCS), which were found to be lower for females of the stress group than the females of the control group. The other half of the mothers of the two groups was used to establish short term stress levels of the glucocorticosterone response. Similar elevations in the stress response for both groups of mothers were obtained. The second part of the study examined the behaviour of the offspring using the open-field. One set of offspring was tested at 45 days of age while another set was tested at 90 days of age. Both ambulation and defecation measures were taken. In addition glucocorticosterone levels were also obtained before and after the open-field testing. The ambulation measure revealed habituation both for animals tested at 45 and 90 days of age. With respect to the defecation measure no significant difference between the groups was obtained at 45 days of age. However, those animals tested at 90 days have a significantly lower defecation score for rats of the stress group as compared to those of the control graup. The major finding of this study is in the glucocorticosterone response. Animals tested at 45 days of age responded with a significant elevation of glucocorticosterone for rats of the stress group as compred with those of the control group. This finding is reversed for those animals tested at 90 days of age. The decrease of glucocorticoids in stressed animals, tested at 90 days of age, can be explained in terms of the traditional view in prenatal psychological stress research, i.e., high levels of 11-OHCS during the prenatal period resulted in a decreased 11-OHCS responsiveness. This is inconsistent with the results obtained at 45 days of age. An alternative explanation is examined which suggests that stressed mothers habituated quickly to the stressor and that during pregnancy pups were subjected to less rather than more of the circulating steroids.

Apparent social effects on open-field behaviour of the rat: A clarification

Abstract Rats housed under group and isolation conditions were exposed in the open-field alone, in naive pairs, paired with a familiar object, paired with an older animal. For both housing conditions a decrease in emotionality was observed only under exposure with the older animal. Exploratory behaviour was not affected. On retest after 35 days no differences were found between exposure conditions but observed differences between housing conditions did hold between test and retest. It was concluded that the major variable in decreased emotionality during paired-exposure, relates to the experience of the co-exposed S and requires only minimal previous contact.

An investigation into the development of melodic interval discrimination

Trotters “melometer” was used to investigate some proposals concerning melody discrimination. An analysis of covariance which controlled for scores on the “Wing Test of Musical Intelligence” showed that discrimination differed in artists, professional musicians and students. The significant difference between the groups indicated three levels of discrimination, one of which was attributed to musical training and the other to some underlying ability common to the Fine Arts. This finding was contrasted with some of Trotters proposals, the method was evaluated and some possible limitations of the experiment given.

Melodic Interval Discrimination and the Influence of Training.

Abstract The influence of training on melodic interval discrimination was examined using 48 Ss. Experimental and control groups were matched on the basis of age, general intelligence and musical intelligence. A test of melodic interval discrimination was administered to all Ss followed by a period of training for the experimental Ss. A second test of melodic interval discrimination was then administered to all Ss. It was found that training improved performance on the second test irrespective of prior formal music experience and that the greatest gains in performance were obtained by Ss with low musical intelligence. Melodic interval discrimination was found to be related to both pitch discrimination and musical intelligence.

Perception of invariants, or “Change”, across transformations of shape and substance?

Abstract Infants between 3 and 4 months of age habituated either to repeated presentations of a shape undergoing, successively, one of two rigid motions, or, to repeated presentations of rigid motion while two shapes were varied successively. A comparable habituation response was obtained for both visual fixation duration and a cardiac measure, change in inter-beat interval. Generally, the results indicated that infants of this age can detect change of shape in a moving object and similarly they can detect change in a particular motion transformation when shape is held constant. Although there was some discrepancy between the results obtained between the visual and cardiac responses during the dishabituation trials the data suggested that infants were responding to change between stimulus events. The notion that infants were able to respond to properties of a stimulus, gained as invariant information from the motion transformation they under-went, was not supported.