Operant conditioning of large magnitude, 12-hour duration,heart rate elevations in the baboon

Two baboons were prepared with arterial and venous catheters and their heart rate and blood pressure were monitored continuously thereafter. Following a 2 to 3 week interval during which baseline cardiovascular levels were determined, the animals were exposed to daily 12 hr conditioning sessions (alternating with 12-hr “rest” or “Conditioning Off’ sessions) during which food reward and shockavoidance were programmed as contingent consequences of pre-specified increases in heart rate. Initially, the criterion heart rate was set at 10–15 bpm above the animal’s pre-experimental resting baseline level, with progressive increases programmed to occur at a rate approximating 7 bpm per week over a period of 8–10 weeks. Within this 2–3 month interval, heart rate doubled, reaching levels maintained above 160 bpm for more than 95 per cent of each daily 12-hour “Conditioning On” period. Propranolol selectively eliminated the conditioned heart rate increase but not the blood pressure elevation, indicating the contribution of sympathetic nervous activity to these operantly conditioned cardiovascular changes.     

Conditional discrimination performance by pigeons on a response-independent procedure

Pigeons were trained on a differential autoshaping procedure in which both components of two-stimulus sequences predicted delivery or nondelivery of food. All birds acquired the conditional discrimination. When the subjects were exposed to an extinction procedure, the stimuli maintained conditional control as long as the birds continued to peck the key. When a delay interval was imposed between the two components of a stimulus sequence using a titration procedure, the stimuli maintained conditional control up to delay values of 7 to 10 sec. These data are consistent with the view that the controlling stimuli in conditional discrimination situations are compounds of stimulus elements.     

Second-order optional avoidance as a function of fixed-ratio requirements

Two rhesus monkeys responded on a fixed-ratio schedule in Stimulus 1 (blue light) to avoid the onset of Stimulus 2 (green light). Failure to avoid Stimulus 2 required a second fixed-ratio performance to avoid Stimulus 3 (red light) in the presence of which unavoidable shock occurred. Relative frequencies of avoidance performance in the blue light and in the green light were inversely related to the ratio requirement under each stimulus condition. Both differential response-cost and avoidance-failure probability factors were related to the observed changes.     

Errors in short-term memory for good and poor readers

This study examined the role of phonetic factors in the performance of good and poor beginning readers on a verbal short-term memory task. Good and poor readers in the second and third grades repeated four-item lists of consonant-vowel syllables in which each consonant shared zero, one, or two features with other consonants in the string. As in previous studies, the poor readers performed less accurately than the good readers. However, the nature of their errors was the same: Both groups tended to transpose initial consonants as a function of their phonetic similarity and adjacency. These findings suggest that poor readers are able to employ a phonetic coding strategy in short-term memory, as do good readers, but less skillfully.     

Complex response patterns during temporally spaced responding

A series of experiments is reported in which two monkeys emitted complex response patterns, not specified by the experimental program, during the DRL component of a multiple schedule. Administration of sodium pentobarbital and dl-amphetamine, drugs which disrupted the DRL performance, were also observed to suppress these collateral responses. Sequences of these collateral responses appear to mediate, at least in part, the timing process required for reinforced performance on the DRL schedule.     

The role of causal attributions in competitive situations

Previous data have shown that successful women are judged to have masculine characteristics [J. A. Doyle (1989), The Male Experience(2nd ed.), Dubuque, IA: Wm. C. Brown; D. L. Gill (1986), Psychological Dynamics of Sport,Champaign, IL: Human Kinetics; D. J. Murphy (1988), “Sport and Gender,” in W. M. Leonard II (Ed.), A Sociological Perspective of Sport(3rd ed.), New York: Macmillan; P. Willis (1994), “Women in Sport in Ideology,” in S. Birrell and C. L. Cole (Eds.), Women, Sport, and Culture,Champaign, IL: Human Kinetics]. Two experiments were conducted to test two different explanations for this effect, the appraisal and attribution hypotheses. In Experiment 1, male participants who lost to a female confederate on a masculine-relevant task rated her as having more masculine and fewer feminine characteristics than when the task was described as feminine-relevant. However, heart rate and blood pressure data failed to support the appraisal hypothesis that these reactions were due to the stress of losing to the female, or defensiveness. The alternative hypothesis that these ratings were due to standard attributional processes was more consistent with the data. Consequently, this hypothesis was tested in Experiment 2 using an attributional paradigm. Consistent with Experiment 1, the attribution hypothesis fared better than did the appraisal hypothesis.     

COGNITIVE PROFILES OF READING-DISABLED CHILDREN:

Abstract— A comprehensive cognitive appraisal of elementary school children with learning disabilities showed that within the language sphere, deficits associated with reading disability are selective. Phonological deficits consistently accompany reading problems whether they occur in relatively pure form or in the presence of coexisting attention deficit or arithmetic disability. Although reading-disabled children were also deficient in production of morphologically related forms, this difficulty stemmed in large part from the same weakness in the phonological component that underlies reading disability. In contrast, tests of syntactic knowledge did not distinguish reading-disabled children from those with other cognitive disabilities, nor from normal children after covarying for intelligence.     

A new device for the application of electrical shock

A new apparatus has been developed for the simple, safe, and effective delivery of electric shock. It delivers a single-pulse high-voltage shock of very short duration. Both voltage and current are easily measured and the applied energy can be calculated. Constant energy applications depend less upon skin contact resistance than is the case with 600-V 60-Hz shockers.