Two auditory aftereffects and their dependency on carrier frequency

It is suggested that aftereffects caused by swept change of sound level (Reinhardt-Rutland & Anstis, Note 1) may contribute to auditory motion aftereffects (Grantham & Wightman, 1979). The latter appear to show selectivity for frequency; they are substantial if the frequency is .5 kHz but not if it is 2 kHz. An experiment was carried out to show to what extent there is such selectivity for aftereffects from swept sound-level change; this showed that they are substantial over a much wider range of frequencies than auditory motion aftereffects. It is concluded that the frequency selectivity of auditory motion aftereffects might be explained by frequency selectivity for inter-aural phase differences.     

Flow thresholds of nonodorous air through the human naris as a function of temperature and humidity

The process of olfactory sensation is probably a Gestalt consisting of motor, physical, and chemical components formed during the transport of the odor-bearing airstream past the olfactory epithelium. In studying a sensory process, it is often necessary to examine the components independently. Apart from its contribution to the olfactory Gestalt, in dynamic olfactometry airflow may distract from, compete with, or mask chemical sensation. Four nonsmoking male subjects were employed to obtain flow thresholds of nonodorous air at eight temperature/ humidity combinations. The stimulus-generating apparatus was housed in a temperature-regulated oven. All materials in contact with the airstream were thoroughly cleaned and were constructed of nonreactive materials to avoid olfactory cues. An evaluation of the quality of the output demonstrated purity. A Béésy technique was used to deliver stimuli via a nasal catheter to the subject. Thresholds were found to be nearly identical for the lowest humidity levels regardless of the temperature. In general, the closer the temperature/humidity was to physiological normal, the higher the threshold. Since the thresholds were so strongly functions of temperature and humidity, it is likely that transduction was by trigeminal thermoreceptive afferents. The utilization of subthreshold flows in olfactory research may reduce the trigeminal component in olfaction, thus permitting better assessment of the contribution of the olfactory nerve to olfactory sensation.     

Saltation through the blind spot

At least three localization illusions can be produced by varying the time relations between two stimuli. Two of these, phi motion and Békésy’s illusion, have been induced in areas lacking receptors. To learn if this also occurred with the third illusion, sensory saltation, people reported their observations when Geldard’s visual rabbit was induced by stimulating points around the optic disk. The rabbit crossed the blind spot as well as other portions of the eyes, and the illusory point was often localized within the region of the blind spot. All three illusions can be localized in an area devoid of receptors.     

Functional Differences Between Upright and Rotated Images

In Experiment I subjects imaged an alphanumeric character either upright or upside-down, and triggered a test display character. Their task was to decide as quickly as possible whether the test character was NORMAL or MIRRORED. On 72% of the trials the test was at the orientation imaged. Reaction time (RT) was then about 200 ms longer in the upside-down image condition. This difference reduced with practice. On the remaining trials the orientation of the test character differed from that of the prepared image. For upright images RT increased monotonically with the angular difference in orientation between test and image. For upside-down images RT did not increase monotonically with angular difference as there was a wide dip around the upright. Further experiments suggested that upside-down images can be rotated, but at considerably slower rates than upright ones, and that the apparent rates of rotation for upside-down images are dependent upon the width of the sector tested. These results indicate that visual short-term memory (STM) and long-term memory (LTM) are distinct; that the process of mental rotation does not operate directly upon LTM; and that functionally, upright and rotated images may differ in important ways.     

Strategies of rule discovery in an inference task

It has long been known that subjects in certain inference tasks will seek evidence which can confirm their present hypotheses, even in situations where disconfirmatory evidence could be more informative. We sought to alter this tendency in a series of experiments which employed a rule discovery task, the 2-4-6 problem first described by Wason. The first experiment instructionally modified subjects confirmatory tendencies. While a disconfirmatory strategy was easily induced, it did not lead to greater efficiency in discovering the rule. The second experiment introduced subjects to the possibility of disconfirmation only after they had developed a strongly held hypothesis through the use of confirmatory evidence. This manipulation also failed to alter the efficiency of rule discovery. In the third experiment, subjects were taught to use multiple hypotheses at each step, in the manner of Platt's “Strong Inference”. This operation actually worsened performance. Finally, in the fourth experiment, the structure of the problem was altered slightly by asking subjects to seek two interrelated rules. A dramatic increase in performance resulted, perhaps because information which in previous tasks was seen as merely erroneous could now be related to an alternative rule. The four studies have broad implications for the psychological study of inference processes in general, and for the study of scientific inference in particular.     

On knowing the meaning of words we are unable to report confirmation of a guessing explanation

This experiment investigated Allport's (1977) claim that normal subjects can be induced to make semantic errors of the type characterised by “deep dyslexia”. The procedure followed that used by Allport except that a subject based control for the chance level of semantic errors was included. The results replicated the original finding by producing a semantic error rate of 12·7%. It was shown, however, that this rate was not significantly higher than the calculated chance rate of 11·5%. It was concluded, therefore, that the semantic error rates reported by Allport can be accounted for in terms of a guessing artefact and thus they bear no relevance to the problem of deep dyslexia.     

Interaction of genetics and separation in canine hyperkinesis and in differential responses to amphetamine

A model of childhood hyperkinesis, using the Telomian-beagle hybrid dog, is described, demonstrating the interactions of genetics and separation in the development of this syndrome and in the favorable responses of some of these dogs to amphetamine. This work represents the collaboration of three laboratories, utilizing chiefly methods of inhibitory training. Inducing separation distress enhanced the resistance to inhibitory training and the favorable responses to amphetamine.     

An animal model of the hyperactive-child syndrome suitable for the study of the effects of food additives

This report describes the use of an animal model for testing the relationship between the effects of ingesting food additives and hyperactivity. Telomian × beagle hybrid dogs were chosen as subjects because this breed has been observed to exhibit behavior seen as analogous to the hyperactivity of children. Two studies were conducted by adding or deleting butylated hydroxyanisole and Food, Drug, and Cosmetic red dye number 40 to the diet of each dog. A test of sitting was performed to measure the level of activity. While a relationship was not observed between the ingestion of the additive and the level of activity, several issues pertaining to the use of the animal model became apparent. These issues and the use of animals for future research in this area are discussed.     

Intracranial cannulation of small animals

Special difficulties are encountered when attempting to provide intracranial cannulation of small animals that have floating or fragile skull bones. The technique described was developed for mice but seems applicable to other species. The cannula system is inexpensive and easy to use. A wound clip anchor seems superior to either skull screws or bonded acrylic, producing less damage to the brain and no necrosis of bone or tissue on the wound margin. Patency data up to 25 days is presented, and the system is as efficacious as other techniques.     

A mutual inductance shocker

A simple dc shock-generating device is described. The principle of operation relies upon the mutual inductance effect between the primary and secondary coils of a transformer.