Serial learning in the pigeon.

Three pigeons learned to peck four colors in a particular sequence, regardless of how these colors were positioned on four response keys and without feedback following each response. This demonstrates that serial learning is possible in subprimate animals.     

Temporal control of behavior and the power law

The performance of rats and pigeons under fixed-interval schedules was studied in two experiments. The duration of postreinforcement pause was a declining proportion of fixed-interval duration. For pigeons this was true both when the duration of the reinforcer was fixed and when it was increased in direct proportion to increases in fixed-interval duration; the longer reinforcer durations did, however, lengthen the postreinforcement pause at higher schedule values. A quantitative analysis of data from Experiments 1 and 2 and from other studies showed that fractional exponent power functions described the relationship between postreinforcement pause and fixed-interval value; similar functions have previously been observed in studies of temporal differentiation. It was concluded that power functions reflect a direct causal, rather than artifactual, relationship between performance and the temporal requirements of reinforcement schedules.     

Oculomotor programming disturbances in the dementia syndrome

Three types of oculomotor programming disturbances are described in patients with the dementia syndrome. This report describes two of these abnormalities, poorly regulated gaze patterns and a programming type of gaze perseveration. All patients showed poorly regulated gaze patterns in contrast to the normal controls, whereas on the whole only the moderately affected patients showed the programming type of gaze perseveration. The third type of oculomotor programming disturbance is efferent perseveration of gaze (a hypokinetic, "staring" type of gaze pattern) and can be seen with severe dementia. The possible significance of these findings is discussed.     

Pupillary attributions of college students to happy and angry faces.

As evidence for an hypothesis that pupil size plays an important role in nonverbal communication, Hess (1975) has reported that adults draw in appropriately sized pupils on his happy and angry faces task. However, he did not report a statistical test of his data. In this study, we replicated Hess' research and found congruent with his hypothesis that college students (n = 223) draw in significantly larger pupils on the happy face.     

Concurrent validity of a children's version of the Stroop Color-Word Test: the Fruit Distraction Test

To assess the concurrent validity of the Fruit Distraction Test, the Stroop Color-Word Test and the Fruit Distraction Test were administered to two groups of boys aged 12 yr. (N = 63) and 8 yr. (N = 52). Partial correlations, with IQ controlled, based on time and error scores derived from both tests, provided no convincing evidence that the Fruit Distraction Test is a valid downward extension of the Stroop.     

Electromyographic tension levels in stutterers and normal speakers

Electromyographic (EMG) recordings of masseter muscle tension during conversational speech by six adult stutterers were compared to EMG levels of 6 normal speakers. Stutterers' and normal speakers' tension levels were significantly different; however, there was no correlation found between level of tension and severity of stuttering.     

Fact and fantasy: the roles of accuracy and variability in confusing imaginations with perceptual experiences

In Experiment 1, pictures were presented to subjects two, five, or eight times, and subjects were asked to imagine each pciture two, five, or eight times. Subsequently, subjects estimated the number of times each picture had been presented. Their estimates of the frequency of these external events were influenced by imagination trials; this effect was greater for good imagers than for poor imagers. Experiment 2 involved a similar design in which subjects were asked either to imagine the same referent for a word or to imagine a different referent for a word on successive imagination trials. Consistency (same referent) did not increase the influence of imaginations on immediate judgments of external frequency. Thus, the results of Experiment 1 were attributed to the greater accuracy (as opposed to greater consistency) of good imagers' internal generations of the stimuli. Furthermore, variation (imagining different referents), like greater accuracy, increased the effects of imagination trials on immediate but not on delayed judgments of frequency. Possible mechanisms underlying these effects are discussed. In general, the two studies show that qualitative characteristics of completely covert generations influence their impact on estimates of the frequency of external events.