Race Differences on a Reading Comprehension Test With and Without Passages

Previous research has found that test takers can score above chance level on reading comprehension tests even when the passages are omitted. The present research investigated whether the effect would vary as a function of race. In Study 1, 386 participants completed a reading test with the passages omitted. General mental ability and race were significantly correlated with test performance. In Study 2, 827 job applicants completed the test as part of an entry-level selection battery. Eliminating items for which large race differences existed in Study 1 had no real effect on the size of the Black-White mean difference.     

The MMPI in evaluation of functional versus organic low back pain

This paper reviews the research literature on MMPI assessment of functional versus organic low back pain (LBP). Research is described in three categories: (a) the relationship between psychopathology as measured by the MMPI and low back pain, (b) MMPI speciality scales, and (c) surgical outcomes. Research, to date, has suffered from methodological problems which has limited generalizations to clinical population. It is suggested, however, that the MMPI can be effectively used with LBP patients, but should not be the only data used in such assessments. Cautions are noted regarding use of the speciality scales.     

Response suppression by visual stimuli paired with postsession d-amphetamine injections in the pigeon

Responding of pigeons, maintained under a fixed-interval 3-minute schedule of food presentation, was decreased on days that the color of the lights illuminating the food magazine was changed and d-amphetamine (1.0 mg/kg, i.m.) was injected after the session. Responding was not decreased by keylight color changes paired with postsession d-amphetamine or by postsession injections of saline. Administration of pentobarbital (3.0 to 5.6 mg/kg), but not d-amphetamine (.3 to 3.0 mg/kg), before the session increased rates of responding suppressed by drug-paired magazine lights. Responding maintained under a fixed-ratio 30-response schedule was not decreased when differently colored magazine lights were paired with a low (.3 mg/kg) postsession dose of d-amphetamine; with high (3.0 mg/kg) postsession doses, however, responding was completely suppressed after two pairings. The effects of pairing magazine stimuli with an intermediate (1.0 mg/kg) postsession dose of d-amphetamine depended upon the magnitude of prior postsession doses. After being paired with a low dose, stimuli paired with 1.0 mg/kg did not suppress responding. After being paired with a high dose, stimuli paired with 1.0 mg/kg completely suppressed responding. The suppression of food-maintained responding by stimuli paired with postsession drug administration depends upon both behavioral and pharmacological variables.     

‘Random’ saccadic eye movements during verbal-linguistic and visual-imaginal tasks

Previous research has suggested that questions eliciting visual imagery are associated with lower rates of saccadic eye movements as compared to questions eliciting verbal processes. Two experiments reported here examined the roles of external visual stimulation and speech output in this effect. In both experiments, questions designed to elicit verbal-linguistic or visual-imaginal processing, and which required either syntactically complex or simple responses, were administered while eye movements were recorded by electrooculography. In experiment 1, 42 subjects responded while viewing either the interviewer's face or a gray oval on a video monitor. Imaginal questions elicited a lower rate of eye movements than did verbal questions regardless of the display on the monitor. In experiment 2, 17 subjects responded in conditions of light and darkness. Imaginal questions elicited lower rates of eye movements in both light and dark. Neither cognitive mode nor speech output requirements interacted with stimulus conditions in either experiment. The failure of visual conditions to influence the verbal-imaginal difference in eye movement rate is viewed as inconsistent with a visual interference interpretation of the relationship of eye movements to cognitive activity. Alternate interpretations are discussed.     

Conjunctive schedules of reinforcement II: response requirements and stimulus effects

Responding of three pigeons was maintained under conjunctive fixed-ratio, fixed-interval schedules where a key peck produced food after both schedule requirements were completed. The individual schedule requirements were then successively removed and reinstated with responding maintained under the following conditions: conjunctive fixed-ratio, fixed-time; fixed-time; and fixed-interval schedules. Patterns of responding changed in accord with the successive removal of the schedule requirements. Compared to the conjunctive fixed-ratio, fixed-interval schedule, pause duration increased and response rate decreased under conjunctive fixed-ratio, fixed-time schedules and under fixed-time schedules alone. Overall mean rates of responding were highest and pause duration lowest under fixed-interval schedules. When changes in the keylight colors were correlated with completion of the fixed-ratio, the end of the fixed-interval, or both of these conditions, the pattern of responding was modified and indicated a greater degree of control by the individual schedules. Although two birds showed large increases in interreinforcement time when they were initially exposed to the conjunctive schedule, when responding stabilized this measure was largely invariant for all birds across most schedule conditions.     

Conjunctive schedules of reinforcement: I. Rate-dependent effects of pentobarbital and d-amphetamine

Key pecking of pigeons was maintained under conjunctive schedules of food presentation in which both a fixed-interval and a fixed-ratio schedule had to be completed before a peck produced food. For two pigeons, pecks on a single key completed both schedule requirements (fixed-interval 3-min, fixed-ratio 50 for one bird, fixed-interval 5-min, fixed-ratio 50 for the second). For two other pigeons, each requirement was scheduled on a separate key. On the two-key schedule, a peck after 5 min on the key scheduling the fixed-interval requirement produced food if at least 10 pecks had occurred on the ratio key (conjunctive fixed-interval 5-min, fixed-ratio 10). When each requirement was scheduled on a separate key, response rates on the fixed-ratio key were generally higher in the early portion of the interval and declined as the interval progressed; responding on the fixed-interval key, once initiated, typically remained at a constant rate throughout the interval. Responding under the single-key schedule was characterized by a high rate early in the interval; this then changed to a lower rate that continued until a peck produced food. For all pigeons, increases in response rates with pentobarbital and d-amphetamine were inversely related to the control rate of responding. When equivalent rates on each key of the two-key schedule were compared, both drugs increased rates on the fixed-ratio key less. Although the effects of both drugs were rate dependent, each drug differentially modified the pattern of responding under the single-key schedule.     

The organization of non-nutritive sucking in the premature infant

Changes in non-nutritive sucking contingent upon the repeated presentation of unpatterned and patterned light stimulation were examined in a sample of 18 premature infants. Stimulus contingent sucking change in chronologically younger infants tended to be somewhat shorter in duration than that of the chronologically older infants and showed stimulus contingent sucking acceleration as well as suppression. Evidence was also found for less orienting among infants showing abnormalities in their sucking behavior. No evidence for habituation was found in any subgroup. Possible factors contributing to the strength and nature of stimulus contingent non-nutritive sucking changes in infants are discussed.