Developmental changes in infants' sensitivity to octave-band noises

Localization responses to octave-band noises with center frequencies at 200, 400, 1000, 2000, 4000, and 10,000 Hz were obtained from infants 6, 12, and 18 months of age. During an experimental trial, an octave-band noise was presented on one of two speakers located 45° to each side of the infant. A head turn to the noise (correct response) was rewarded by activating an animated toy on top of the speaker. The intensity of the noise was varied over trials (method of constant stimuli) to determine thresholds at each center frequency. Thresholds for the lower frequencies were approximately 5–8 db higher in the 6-month-old infants compared to the older infants. However, there were no consistent differences among groups at the higher frequencies. Infant thresholds were found to be 20–30 db higher than adult thresholds at the lower frequencies. At the higher frequencies thresholds for infants were approaching those of adults.     

Conditioned suppression of drinking: A measure of the CR elicited by a lithium-conditioned flavor

The CR elicited by an exposure to a lithium-conditioned flavor CS+ was measured in a paradigm which closely approximated traditional conditioned suppression of licking. Rats were first trained to discriminate between a lithiumpaired flavored solution (CS+) and an equally familiar, but safe, flavored solution (CSc). Then, while they consumed a differently flavored test solution, the rats were intraorally infused with either the CS+ or the CSc flavored solution. The immediate aftereffect of the CS+ exposure on consumption of the Test Solution (TS) measured the CR. The CS+ exposure suppressed the consumption of both a novel flavored TS and an unflavored water TS. The strength of the suppressive CR was influenced by the nature of the TS and by the dose of lhe lithium US.     

Stimulus control of spatial behavior on the eight-arm maze in rats

Rats were trained on an eight-arm, elevated radial maze in a large cylindrical chamber where extramaze stimuli could be manipulated. The first experiment indicated that rats could use extramaze stimuli to locate the arms if such stimuli were available, whereas they performed less effectively and tended to employ response chaining if these stimuli were not available. The second experiment demonstrated that maze performance was disrupted by transposition of the stimuli but was relatively unaffected by rotation of the same stimuli. The third experiment suggested that the disruptive effect of stimulus transposition might be due to a “resetting” process elicited by the alteration in the configuration of the stimuli after stimulus transposition. These results suggest that when extramaze stimuli are available, rats tend to use such stimuli in a configurational manner to locate the arms rather than as a list of items processed independently of their spatial relationships to each other.     

Caffeine ingestion,misattribution therapy,and speech anxiety

While theoretical analogs of misattribution therapy appeared promising (Nisbett & Schachter, 1966; Ross, Rodin, & Zimbardo, 1969), attempts with clinically relevant behaviors have not been so successful (Kellogg & Baron, 1975; Singerman, Borkovec, & Baron, 1976). Since the plausibility of the misattribution manipulation appears to be the central problem, the present study attempted to increase plausibility by manipulating familiarity with the setting and actual psychological arousal in a clinically relevant situation. Subjects only slightly fearful of giving speeches presented a speech in front of two observers. Familiarity was varied by having half of the subjects give a pretest speech, while arousal was manipulated by having half of the subjects ingest caffeine while the others ingested a placebo just prior to the test speech. The subjects' attributions were varied by giving them either arousal or irrelevant symptom instructions regarding the effects of the ingested drug. Direct suggestion rather than misattribution effects occurred: Those subjects receiving arousal symptoms reported more nervousness than subjects who had received irrelevant symptoms. The authors conclude that while the misattribution effect may have experimental validity, it is not effective with clinically relevant behavior.     

Exposure to inescapable shock produces both activity and associative deficits in the rat

Interference with shuttle-box escape learning following exposure to inescapable shock is often difficult to obtain in rats. The first experiment investigated the role of shock intensity during escape training in the apparent fragility of the effect. Experiment 1A demonstrated that the magnitude of the interference effect was systematically related to shock intensity during shuttle-box testing. At .6 mA, a robust effect was obtained, whereas at .8 mA and 1.0, little or no deficit in the escape performance of inescapably shocked rats was observed. Experiment 1B demonstrated that the deficit observed in Experiment 1A depended upon whether or not rats could control shock offset. Experiment 2 suggested that preshock may suppress activity and that higher shock levels may overcome this deficit. Experiment 3 tested this as the sole cause of the escape deficit by requiring an escape response which exceeded the level of activity readily elicited by a 1.0-mA shock in both restrained and preshocked rats. In such a task, preshocked rats performed more poorly than did restrained controls. These results are consistent with the possibility that inescapable shock may, in addition to reducing activity, produce an associative deficit. Experiment 4 more clearly demonstrated that inescapable shock produces deficits in performance which cannot be expleined by activity deficits and which appear to be associative in nature. It was shown that inescapable shock interfered with the acquisition of signaled punishment suppression but not CER suppression. The theoretical implications of these data for explanations of the manner in which prior exposure to inescapable shock interferes with escape learning were discussed.     

Intelligence and the processing of stimulus structure

It has been demonstrated in a number of experiments that the difficulty level of several performance type intelligence test tasks is determined directly by stimulus and task variables that vary the information to be processed. The variables are quantifiable. The implications of these findings for intelligence and the problems of an experimental approach to the measurement of intelligence are discussed.     

The cognitive basis of the comprehension and production of relational terminology

The comprehension of big, little, and same number and the productio of relational terminology was assessed in 168 preschool children. Stimuli were used which varied the relationships of length, number, and density. Language comprehension and production were related to the complexity of cognitive operations required by the task. Specifically, comprehension was easier in the situations in which length and number were positively correlated than when length provided no cue to number. Comprehension was most difficult when length and number were negatively correlated. There was asymmetry in language comprehension such that the positive term big, was comprehended earlier than little in some tasks; there was also asymmetry in production in that the child was more likely to use language related to the positive pole than to the negative pole. These data were interpreted as providing support for theories of the cognitive basis of language acquisition.