A case of cortical deafness: Clinical and electrophysiological data

A patient suffering from a primary myocardiopathy is suddenly no longer able to recognize speech and environmental sounds, in spite of good peripheral hearing; he remains able to speak, read, and write. The C.T. scan shows lesions involving both supratemporal planes. The cortical sensory deficit documented by the absence of late acoustic evoked potentials leads to a diagnosis of cortical deafness rather than of auditory agnosia.     

Sensory stores and high-speed scanning

A model of scanning based on separate sensory and short-term stores was suggested and tested. The experiment used a probe recognition method, with set size varied from 1 to 8 and a fast presentation rate. A masking procedure was used to vary the number of items available in a possible sensory store. Although conditions were such as to maximize the chances of detecting an effect, none was found: the possible size of the sensory store had no effect on reaction time whatsoever. Other aspects of the data lent little support to a serial exhaustive scanning model, but a previously proposed parallel processing model fared better. Finally, not only was the function for positive probes steeper than that for negative probes but also there was a crossover effect as well. This crossover is not without precedent and may indicate the need for consideration of both accuracy and latency in high-speed scanning studies.     

Influence of accommodation on the viewing of an optical illusion

This study demonstrates the role of microfluctuations of accommodation in the viewing of the concentric ring illusion. Four experiments were carried out. Experiment I consisted of changing the distance between the illusion and the eyes but retaining visual angle, luminance and pupil size constant. In Experiment II, the accommodation of the eyes is paralysed by a cycloplegic. In Experiment III, the illusion is shown to a monocular aphakic and in Experiment IV, the exposure time is varied between 1/100 and 5 sec. Furthermore, a series of observations compared the concentric ring illusion seen with both eyes simultaneously. The evidence provided by the results of these experiments plus others discussed provide evidence that the concentric ring illusion is caused by the microfluctuations of accommodation.     

Sensory scaling and the psychophysical law

Sensory scaling is analysed as a sensori-motor task for which two relations must be determined, the first, S = f(I), being the relation between I, the stimulus intensity, and S, a measure of the neural effect of the stimulus, and the second being the relation between the subject's response, R, and S. It is shown that for any scaling procedure the relation between R and S can be arbitrarily specified, and according to the choice made S = f(I) will be found to be either a power function or a logarithmic function; these two “psycho- physical laws” do not reflect empirical differences between scaling procedures but conventional differences in the assumptions made when interpreting these procedures. A model is then elaborated in which S = f(I) is fixed and the relation between R and S depends on the demands of the psychophysical task and the effects of previous learning. With this more complex model the empirical implications of the power function and log function differ; it is shown that if the latter is accepted explanations can be given for two major problems in scaling theory, the disparity between the functions given by category scaling and the direct methods, and the difference between prothetic and metathetic continua.     

Health and legal issues in undercover narcotics investigations: Misrepresented evidence

This paper outlines some types of psychological disturbances found to occur in narcotics agents who use undercover investigative methods. Research results and other clinical findings dismiss popular notions of multiple personalities as a mental injury caused by prolonged role played pseudoidentities. Coping strategies for dealing with certain paranoid reactions are seen as potential sources of contamination in the gathering of evidence of criminal activity. Issues related to questions of health versus operative talents in selecting for personal suitability for undercover work are presented.     

Contribution of nesting experience to progesterone-induced incubation in ring doves (Streptopelia risoria)

Injections of progesterone induce incubation behavior in gonadally intact ring doves only if the doves have had previous experience with at least the nest-building phase of a breeding cycle. The present study was designed to determine whether exposure to progesterone during the nest-building phase is sufficient to account for the ability of progesterone to induce incubation at a later time or whether some other factor provided by experience with this phase of the cycle is needed. Six groups of 10 pairs of doves each were provided with different combinations of experience and progesterone priming. Progesterone priming combined with social isolation or with courtship experience had no significant effect on subsequent progesterone-induced incubation. However, doves that participated in the nesting phase of the cycle during progesterone priming later incubated in response to progesterone treatment. Nesting activity, which may or may not include building the nest, seemed to be the relevant experience.     

The motivational implications of adolescents' school‐oriented possible identities in a social change context

In line with the identity‐based motivation theory (Oyserman, 2015), which postulates that the motivational implications of possible identities depend on social context, the present research argues that the interplay between accessible possible identities and motivation is also influenced by adolescents' perceptions of social change. According to social identity theory (Tajfel & Turner, 1986), perceptions of social change were conceptualized as intergroup comparison outcomes, which are assumed to influence the motivational implications of possible identities under the condition that the social change process is perceived as insecure. The results of the present study, which surveyed 631 South African adolescents, supported our assumption. For instance, Black township participants' motivational implications of their possible identities were informed by their identification with Black South Africans. However, the results with regard to white suburb and Black suburb participants were rather ambiguous. The theoretical and practical implications of these findings are discussed in detail.