Two visual mechanisms underlying the behavior of fish

Summary Studies of motion-detection by fish reveal two separate processes, which are hypothetically linked to different kinds of behavior. Furthermore, studies of interocular transfer with mirror-image shape discriminations also indicate two distinct mechanisms for the representation of visual directions. From these two kinds of experiment, it seems that visual processes subserving orientation of the fish to a moving object should be clearly distinguished from processes by which the fish evaluates the identity or activity of the object.

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Zusammenfassung Untersuchungen der Bewegungswahrnehmung von Fischen zeigen zwei verschiedene Prozesse auf, die mit zwei verschiedenen Verhaltensweisen in Beziehung gesetzt werden. Eine Analyse des interokularen Transfers mit Unterscheidung spiegelbildlicher Formen läßt außerdem erkennen, daß zwei verschiedene Mechanismen für die Repräsentation visueller Richtungen verantwortlich sind. Aus diesen Experimenten wird geschlossen, daß jene visuellen Prozesse, welche der Orientierung des Fisches in bezug auf ein sich bewegendes Objekt dienen, scharf unterschieden werden sollten von denen, durch welche der Fisch die Identität oder Aktivität des Objektes beurteilt.

     

Student Attendance at University Co-curricular Activities

Over 18,000 students at Michigan State University reported their attendance at 46 campus events. Student characteristics were analyzed in terms of student attendance patterns. The 46 events were grouped into 4 independent categories that were attended by students with different characteristics. Students who attended cultural events were mostly single upperclassmen majoring in liberal arts; musical events were attended mostly by music majors; those attending athletic events tended to be single male undergraduates from the more applied disciplines; and social events were attended mostly by undergraduate girls.     

Intake and Walk-in Procedures in a College Counseling Setting

Modifications of the intake procedure usually employed in counseling settings were adopted in order to provide students the opportunity for immediate contact with a counselor. Elimination of the waiting list, reduction in number of missed appointments, and reduction of length of counseling came about. Staff satisfaction with the new approach has been high and there would be opposition to reverting to the scheduled initial interview. Possible changes in the type of problem or clients' readiness for problem-solving were observed.     

Two types of phenomenal instructions for size and distance judgments of objects presented on a two-dimensional plane

Demand characteristics were studied in a simple situation in which observers made size and distance estimates of stimuli presented on a two-dimensional linear perspective drawing. Half the Ss were asked questions stressing phenomenal report: The other half were asked the same questions preceded by instructions stressing the objective nature of the stimulus configuration but requesting, nonetheless, phenomenal report. Instructions resulted in a significantly greater perspective size illusion but did not affect the distance estimates. No meaningful correlations between size and distance estimates were found.     

A simple histological technique for localizing electrode tracks and lesions within the brain.

Histological procedures are necessary in brain stimulation or lesion work to determine the neural area which has been stimulated or damaged. Preparation of brain tissue often involves embedding and staining techniques that require specialized training, and the expense of a technician and a large assortment of special apparatus and supplies. In addition, the results of such techniques are unavailable for at least several days. A photographic method, which requires little special skill and a minimal amount of apparatus, is described here. Results can be available within minutes after the subject is sacrificed. This method has been shown to be adequate for the gross determination of lesion boundaries and electrode or cannula tip loci in brains of rats, cats, and squirrel monkeys.