Levels, hierarchies, and the locus of control

The Bartlett--Craik view of human performance is restated; and particularly that it is organised at different levels. On that view, the lower levels are controlled by the upper but capable of functioning independently. Modern views of memory, language, and problem-solving are compared with this doctrine, and found to embody some of its virtues but not all. Fresh experiments are described, in which people take decisions about the running of a transportation system. The simplest control mechanism which will model their behaviour is a two-level adaptive controller.     

Orthographie distinctiveness of homonyms

Ratings of orthographic distinctiveness were obtained for 139 homonym pairs. Mean ratings on a 9-point scale ranged from 7.75 to 2.44. Reliability of the ratings was high (r = .91). In addition, orthographic distinctiveness was found to be independent of disparity in perceived meanings of the separate homonym forms.     

One-trial-a-day avoidance learning

A one-trial-a-day discrete-trial avoidance conditioning procedure run for 30 consecutive days was compared with a massed-trial procedure where Ss received 30 consecutive trials within 1 day. The Ss in both groups were equated for time each S spent in the nonshock compartment of the apparatus, number of times the transport box carrying Ss was lifted out of the nonshock compartment, and the number of times each S was handled. The main difference between groups was the intersession trial length of 24 h for the one-trial-a-day Ss. Learning was rapid for both groups. The groups did not differ reliably on six acquisition indices. The methodological advantages of the one-trial-a-day procedure and its theoretical importance were discussed.     

Perceptual masking: Peripheral vs central factors

Perceptual masking was studied under binocular and dichoptic conditions in order to separate peripheral and central interference effects. Under binocular conditions, when the test flash (TF) and the blanking flash (BF) fell on both retinas, both retroactive and proactive masking were demonstrated. Under dichoptic conditions, when the TF fell on one eye and the BF on the other eye, thus eliminating opportunity for intraretinal interference, there was partial retroactive perceptual masking and no proactive masking. These results suggest that binocular proactive masking is due to peripheral light adaptation, that binocular retroactive masking is due to both peripheral and central effects, and that dichoptic masking is due solely to central retrochiasmal interference. It is proposed that dichoptic retroactive perceptual masking affords a method of investigating central perception time, i.e., the time to consolidate a perceptual experience.     

Human visual motion sensitivity: Evidence against a ratio theory of sensory coding

Luminance thresholds for downward moving contours were measured under several conditions of adaptation. Included was one condition which desensitized visual mechanisms responsive to downward motion. Another condition exerted equal effects on both up- and down-sensitive mechanisms. Thresholds for moving contours were unaffected by exposure to contours which moved in the opposite direction. This indicates that the perception of motion does not depend upon the relative activity in oppositely tuned, directionally selective visual mechanisms.     

Relational and absolute cues in auditory discrimination by monkeys

Rhesus monkeys were trained to make auditory frequency, intensity, and duration discriminations. Initial training was carried out with a procedure which allowed the utilization of either relational cues or absolute cues. Later tests with similar auditory parameters allowed only the utilization of relational cues. Performance on these latter tests indicated that relational rather than absolute cues had been utilized when both types were available on the frequency and intensity discrimination tasks. However, absolute rather than relational cues were apparently utilized in making duration discriminations.     

Taste and water taste of twenty-six compounds for man

Taste profiles were obtained for 26 compounds after adaptation to distilled water and also for water after adaptation to each of the 26 compounds. Each of the four “basic tastes” was induced in water by adaptation to certain of the compounds. Compounds having similar tastes did not necessarily have similar water tastes. The results imply a peripheral locus of the water taste mechanism(s).     

A feature utilization analysis of the perception of pattern class structure

Patterns were computer-generated about two prototypes to form schematic clusters of three diameters about the cluster centroids. In a schematic concept-formation task, recovery of a priori schematic class membership by Os varied inversely as physical cluster diameter, with concept acquisition across trials evidenced in only the low-cluster-diameter condition. For each 0 who failed to classify according to the schema rule, linear discriminant function analysis was applied to his classes. In all cases, O-generated classes were successfully recovered by the physical pattern features used as predictors, the mapping of these classes by the LDF exceeding that by the schema rule in accuracy at all cluster-diameter levels.     

Testing the significance of interobserver agreement measures in the presence of autocorrelation: The jackknife procedure

Users of interobserver agreement statistics have heretofore ignored the problem of autocorrelation in behavior sequences when testing the statistical significance of agreement measures. Due to autocorrelation traditional reliability tests based on the 2 × 2 contingency-table model (e.g., kappa, phi) are incorrect. Correct tests can be developed by using the bivariate time series as a statistical model. Seen from this perspective, testing the significance of interobserver agreement becomes formally equivalent to testing the significance of the lag-zero cross-correlation between two time series. The robust procedure known as the jackknife is suggested for this purpose.