Biomedical subjects

O O Rydén

Publications and source records attributed to O O Rydén.

4 recordsLinked to original sources

PubMed1987

Relationship between differentiation and integration of self and nonself: an investigation in terms of modes of perceptual adaptation.

Differentiation and integration of self- and nonself-aspects of perception were investigated as features of the process of adapting to a spiral aftereffect (SAE) induced with massed trials. The cessation of the SAE at each trial was assumed to indicate that self-aspects of perception had been differentiated from nonself-aspects, changes in SAE duration over trials being considered to represent the integration of these aspects. Degree and stability of self-nonself-differentiation, reflected in the level and persistence of field-dependence measured on a serial version of the Rod and Frame Test, varied between individuals (N = 129). The results suggest that persistent field-independence requires both self- and nonself-aspects of perception to be adequately and continuously represented in an integrative process which is oriented towards stimulus-proximity, self-aspects of perception being successively replaced by nonself-aspects.

Adaptation, Psychological↗

PubMed1986

Field-dependence/independence: ability in relation to mobility-fixity.

Previous authors have pointed out that, while the classic Rod-and-Frame Test (RFT) yields a measure of ability to perform field-independently, it is unsuitable for identifying stylistic preference, such as mobility-fixity within the field-dependence/independence dimension. To relate mobility-fixity and ability aspects of field-dependence/independence, we compared data obtained from two versions of the test: one with a "free" instruction, on which the subjects were invited to adjust the rod to any position(s) they preferred on each of 10 trials and a process-oriented version (RFT-P), involving 20 trials with the standard instruction but with a constant rod-and-frame configuration, making possible analysis of the process of adaptation. Mobility versus fixity was defined in terms of more or less frequent changes of rod positions and choice of a high or a low proportion of nongeometrical positions in the RFT-Free. 38 female and 23 male university students completed first the RFT-Free and thereafter the RFT-Process. Women were more field-dependent than men throughout the RFT-Process trials; there were no differences between the sexes over trials or in choice of positions in the RFT-Free. Compared with field-dependent subjects, field-independent subjects more often changed rod positions in the RFT-Free and preferred nongeometrical positions somewhat more. Among field-independent subjects, those with consistently low deviations in RFT-Process more often preferred a variety of nongeometrical positions in RFT-Free than did those with gradually increasing deviations. We conclude that field-independence is associated with mobility and field-dependence with fixity, as defined by the RFT-Free variables, and that a prerequisite for high mobility is a relative stability of field-independence as reflected on the RFT-Process. Theoretical implications of this conclusion are discussed.

Adult↗

PubMed1982

Selective resistance to approach: a precursor to fear responses to an alarm call in great tit nestlings Parus major.

The reactions of 10-day-old great tit nestlings to 3 auditory stimuli were studied. The stimuli, presented on a series of feeding occasions, were (1) the species' "sweet" alarm call, (2) a song strophe of the great tit, and (3) a song strophe of the tree-creeper (Certhia familiaris). In contrast to earlier findings in studies of older nestlings, these younger nestlings did not respond to the alarm call with cessation of begging. However, a significant differential effect of the alarm call was demonstrated when the conditioning rates for the nestling' begging response to each of the 3 stimuli were determined. Thus, conditioning was significant slower to the alarm call than to the other stimuli. The results agree with the general conception that responses to species-specific calls develop gradually during early ontogenesis. Thus fear responses to the alarm call, such as cessation of begging and "freezing," which are elicited in newly fledged young, are preceded by weaker aversive tendencies that are not obvious from observations of the nestlings' behavior in nature. It is suggested that the nestlings' exposure to contrasting auditory stimulation-their own begging call and the parental feeding call-constitutes the experiential base for withdrawal responses to the "sweet" call.

Animals↗

PubMed1980

Heart rate response in great tit nestlings (Parus major) to an alarm call.

Nine great tit nestlings were exposed to two synthesized auditory stimuli: a replica of a high-pitched alarm call, a part of the species' vocal repertoire, and a control stimulus, identical to the alarm call with respect to amplitude, duration, frequency span, and frequency modulation but having a lower frequency range (8.6--8.1 kHz vs. 4.5--4.0 kHz). The alarm call released a defensive reaction characterized by (a) a prolonged heart rate (HR) acceleration, (b) increased electromyographic activity, and (c) behavioral immobility. The control stimulus elicited a transient HR acceleration and a muscular reaction indicative of a startle reflex. It is concluded that high pitch is a critical feature of the alarm call. It is proposed that the impact of the alarm call is a consequence of the nestlings' primary experience with sounds in the low to middle frequencies, in particular, with the parental feeding call and their own begging call. Embryological maturation of auditory responsiveness, starting with a sensitivity to low-frequency sounds, may contribute to the establishment of a basic tendency to approach low-frequency stimulation and show aversive reactions to high-frequency stimulation. In contrast to earlier interpretations, it is suggested that a strong accelerative HR response is not associated with a reduced stimulus sensitivity per se but rather with an altered distribution of attentiveness.

Acoustic Stimulation↗