Stage 2 processing and the divided-attention effect

In two experiments subjects performed a choice-reaction-time (CRT) task and a second task concurrently. The second task was a simple reaction-time task in Experiment 1 and sentence generation and recall tasks in Experiment 2. Both studies yielded two main findings: Performance of the second task was not affected by CRT memory load (one, two, or four items), and the requirement to perform the second task did not affect the rate of increase of CRT with memory load. The first finding indicates that the effect of memory load on CRT is attributable to memory scanning, or Stage 2 processing, and is not an artifact of the rehearsal demands of the CRT memory set. The second finding indicates that Stage 2 processing is not sensitive to division of attention between the CRT and a second task.     

Perceptual differences between reading handwritten and typed words

Perceptual differences between reading handwritten and typed words were investigated in a series of three experiments. In the first two experiments, a Sternberg memory search paradigm was employed, with either typed or handwritten probes. The reaction time to classify handwritten probes was slower than for typed probes, but memory search took place at the same rate for both kinds of probe. In the third experiment, the latencies for naming the written and typed words differed by the same amount of time as the overall difference between the same stimuli in the memory search task. These findings indicate that only perceptual processes are differentially affected by the differences between typed and written words. Furthermore, in these tasks the independence of encoding and memory search makes it unlikely that processes of perceptual indentification use expectations or analysis-by-synthesis based on the information in immediate memory     

A biphasic 60-Hz synchronizer circuit for the recording of visually evoked responses in high-noise environments

A simple synchronizer clock circuit is described that aids in the rejection of 60-Hz noise from evoked potential measurements.     

Measuring circadian cycles: A simple temperature recording preparation

While measurement of temperature as an index of circadian rhythmicity is not a difficult task with infrahuman subjects, long-term monitoring of deep body temperature with human subjects poses numerous measurement and safety problems. A preparation is described that is highly accurate, inexpensive, chronic, comfortable, and eliminates safety problems associated with more traditional methods of temperature measurement.     

A study of some conditions relating to the retarded adult's stereotyped responding in a binary-choice task

This study was a longitudinal one that examined the effects of certain conditions on alternation and perseveration in a binary-choice task. The conditions manipulated included: (1) lapse of time (stability of the pattern), (2) stimulus dissimilarity, (3) spatial location of the two alternatives, (4) time-out (time away from the task), (5) delay between responses, and (6) differential reinforcement of the two choices. Eight mentally retarded adults, identified as “pure” alternaters or perseveraters, served as subjects. Perseveration was “disrupted” only by differential reinforcement. Alternation was affected by all experimental manipulations with the exception of stimulus dissimilarity.     

Is the discrimination of motion-path length unique?

Discrimination of the extent of a motion path may present a special problem since the discrimination calls on memory for changing position and involves pursuit movements of the eye. To determine how these factors affect judgment, discrimination of extents represented by motion paths, successively appearing endpoints, and simultaneously present endpoints was compared under a variety of eye-movement conditions: fixation, pursuit, and saccadic. Discrimination was assessed by the method of adjustment and also by the method of magnitude estimation. Discrimination of motion path extent was found to be as accurate as discrimination of an interspace demarcated by simultaneously presented points or by successively presented points. This was true for brief single presentations of the extents as well as for repeated exposures to the extents. The findings were applied to the analysis of the perception of velocity and the perception of extent.     

Operant conditioning of the EEG in two patients with epilepsy: Methodologic and clinical considerations

Methodologic and clinical considerations are discussed in sensorimotor rhythm (SMR) biofeedback research on two dissimilar but severe epileptic males. The first case, an akinetic epileptic who prior to feedback training experienced 80–100 clinical seizures every 10 hours, showed considerable seizure reduction after 6 months of SMR and epileptiform training. A number of methodologic and instrumentation advances were pioneered with the akinetic patient: (1) development of and ultra-sharp band-pass filter; (2) use of epileptiform inhibit and feed-back circuitry; (3) use of monetary rewards as additional incentive; (4) use of correlational analysis for evaluation of acquisition in the major dependent variables and; (5) use of noncontingent feedback and rein-forcement as control techniques. The second case, a psychomotor epileptic, also showed therapeutic benefit from SMR training. Clinical information regarding the effect of anticonvulsant medications on the course and therapeutic outcome of SMR training are described. In conjunction with operant conditioning of 12 Hz activity, corresponding changes for other EEG parameters are examined.