Caffeine,impulsivity, and memory scanning: A comparison of two explanations for the Yerkes-Dodson Effect

Two explanations for the Yerkes-Dodson Effect (1908) were tested. Easterbrook (1959) proposed that arousal reduces the range of cue utilization. Thus, arousal should interfere with the capacity for simultaneous (dual) memory scans. In contrast, Humphreys and Revelle (1984) proposed that arousal facilitates sustained information transfer but interferes with short-term memory. Arousal should thus reduce the time needed to prepare to respond but increase the time needed to scan memory. Either caffeine or placebo was given to 78 subjects who differed in impulsivity. They completed three versions of a memory-scanning task: two single-task versions (physical and category matches) and one dual-task version (either type of match). As predicted by Humphreys and Revelle, relative to placebo, caffeine lowered the intercept (p<.01), suggesting facilitation of sustained information transfer, but increased the slope (p<.05), suggesting impairment of access to short-term memory, of the regression of reaction time on log-transformed memory-set size. That caffeine had a main effect on slopes and on intercepts but did not interact with type of task suggests that arousal does not necessarily disrupt dual-task performance.     

Human patellar reflex and conditioned reflex compared electromyographically

Inspite of continued work on the stretch reflex and “voluntary” movement study of the conditioned stretch reflex declined early in this century. The present experiments surveyed seven classical conditioning regimens for the human rectus femoris EMG seen after a blow to the patellar tendon. It was possible to (1) rule out conditioning to a knee touch that occured together with the tap, (2) establish weak conditioned stimulus, Sc, control for a tape recorder click and subsequent fist clench that preceded the tap by variable elapsed times, and (3) establish strong Sc control for a tone that sounded an invariant 0.27 sec before the tap. There were large differences, however, in Sc power across subjects, as measured by amplitude, latency, and frequency of conditioned EMG activity that occured prior to tap or when the tap was omitted. Purely reflexive responses, especially later EMG segments, also varied in amplitude and frequency, to support a conclusion that numerous controlling stimuli added or competed from trial to trial. Further disclosure of Sc contributions, including those from movement-generated stimulation, is warranted, especially for behaviors whose rhythmic timings, as in locomotion, might favor Pavlovian conditioning.     

Changes in Moods and Activation Levels During the Menstrual Cycle in Experimentally Naive Subjects

Two experiments providing additional validity data on the Profile of Mood States and the Thayer Activation-Deactivation Adjective Check List were per-formed. In the third and main experiment, seven normally menstruating women filled out both questionnaires at the same time every day for 90 days. They were not aware that they were participating in a study of menstruation. Analysis of the time series records of individual women revealed relatively few significant fluctuations in moods and activation levels. Analysis of the group data showed that Fatigue, Confusion, Deactivation/Sleep, and Depression/Dejection were significantly lower in the premenstrual phase than in the periovulatory phase of the cycle, while General Activation was higher. Anger/Hostility and Confusion were both lower in the menstrual phase than in the periovulatory phase. On a retrospective menstrual distress questionnaire, these same subjects say that they experience increases in anxiety, irritability, depression, and tension in the premenstrual phase of the cycle. The differences between individual and group data and the apparent discrepancy between daily self-reports and retrospective questionnaires are discussed.     

Comparability of methods of observation for global ratings of heterosexual social skill and anxiety: A generalizability study

This research examined the degree to which skill and anxiety ratings vary as a function of audio, video, or live rating conditions. The question was addressed through a generalizability analysis which indicated that ratings of skill may generalize across audio, video, or live rating modes and across judges within a mode. However, results for anxiety show that while one can generalize across modes, there is a lack of comparability across judges within modes. This finding indicates the need for more judges in order to obtain acceptable levels of reliability for anxiety. Additional validity analyses suggest that the use of videotapes for ratings of skill maximizes the information obtained from role-play techniques for the assessment of heterosexual social performance.Appreciation is expressed to Jan Wallander, Betsy Firth, Dave Ward, Susan Keane, and Judy Dygdon, without whom this project could not have been completed.     

Differences in matching-to-sample performance with element and compound sample stimuli in pigeons

This series of experiments examined zero-delay matching-to-sample performance in pigeons with element and compound sample stimuli. In Experiment 1, compound sample stimuli were consistently followed by compound comparison stimuli and matching accuracy during testing was equivalent to element sample-element comparison trials on the color dimension. In Experiment 2, element comparisons suddenly introduced following compound samples produced a decrement on the line dimension only. Subsequent testing at various sample durations revealed higher matching accuracy following element samples than following compound samples on both the color and line-tilt dimensions. Experiment 3 replicated the results of Experiments 1 and 2 and also demonstrated that the superiority of element over compound matching performance remains constant over the sample durations tested. In Experiment 4 testing at sample durations up to 30 sec produced an overall decrement in matching performance, but again the element vs compound matching difference remained constant. The stimulus-generalization decrement hypothesis provided a better explanation of these results than either the information-overload hypothesis or the rule hypothesis.     

Analogical problem solving

The use of an analogy from a semantically distant domain to guide the problemsolving process was investigated. The representation of analogy in memory and processes involved in the use of analogies were discussed theoretically and explored in five experiments. In Experiment I oral protocols were used to examine the processes involved in solving a problem by analogy. In all experiments subjects who first read a story about a military problem and its solution tended to generate analogous solutions to a medical problem (Duncker's “radiation problem”), provided they were given a hint to use the story to help solve the problem. Transfer frequency was reduced when the problem presented in the military story was substantially disanalogous to the radiation problem, even though the solution illustrated in the story corresponded to an effective radiation solution (Experiment II). Subjects in Experiment III tended to generate analogous solutions to the radiation problem after providing their own solutions to the military problem. Subjects were able to retrieve the story from memory and use it to generate an analogous solution, even when the critical story had been memorized in the context of two distractor stories (Experiment IV). However, when no hint to consider the story was given, frequency of analogous solutions decreased markedly. This decrease in transfer occurred when the story analogy was presented in a recall task along with distractor stories (Experiment IV), when it was presented alone, and when it was presented in between two attempts to solve the problem (Experiment V). Component processes and strategic variations in analogical problem solving were discussed. Issues related to noticing analogies and accessing them in memory were also examined, as was the relationship of analogical reasoning to other cognitive tasks.     

The development of grapheme-phoneme correspondence in normal and dyslexic readers

The present experiment was concerned with the development of grapheme-phoneme conversion ability in normal and reading-age matched dyslexic readers. The use of grapheme-phoneme correspondences was observed in a recognition memory task for pronounceable nonwords. The nonwords were presented in either the visual or auditory modality and had to be recognized immediately from the converse modality, thus necessitating decoding of stimuli across modalities. The use of grapheme-phoneme correspondences increased with reading age in the normal readers but not in the dyslexics. It was postulated that dyslexics have a specific difficulty in grapheme-phoneme conversion. For them an increase in reading age is attributable mainly to an increase in size of sight vocabulary.     

The role of loudness in auditory imagery

Four experiments studied characteristics of auditory images initiated by named but unheard sounds. The sounds varied in their loudness ratings. As the difference between the loudness ratings of the two sound phrases increased, the times to mentally equate the loudness of the two images increased, whereas the times to identify the louder (or softer) of the images decreased. Moreover, congruity effects were found in the comparative judgment task: Times were faster to identify the louder of two loud-rated stimuli than to judge the softer of the same two stimuli, and times were faster to identify the softer of the two soft-rated than two loud-rated stimuli. The loudness ratings did not always influence performance, however, for neither an image generation nor a reading task showed response times that varied with loudness ratings. These results suggest that sensory/perceptual components are optionally represented in auditory images. These components are included when appropriate to a given task. A control experiment showed that the results cannot be considered epiphenomenal.