Time-place learning by pigeons, Columba livia

In each of two experiments, 2 pigeons received discrimination training in which food reinforcement for key pecking was conditional upon both spatial and temporal cues. In Experiment 1, food was available for periods of 30 s at each of three locations (pecking keys) during trials that lasted 90 s. In Experiment 2, food was available for periods of 15 min at each of four locations (pecking keys) during a 60-min trial. In both experiments, pigeons' key pecking was jointly controlled by the spatial and temporal cues. These data, and other recent experiments, suggest that animals learn relationships between temporal and spatial cues that predict stable patterns of food availability.     

New perspectives on child and adolescent depression

The Children's Depression Index (CDI) was administered to a group of 304 regular school students in Grades 3–12. It was found that 21% of the students reported mild to moderate levels and 7% reported severe levels of depression. Females reported more overall depression than did males. Specific CDI items selected more frequently by females than by males supports previous work suggesting that females tend to internalize difficulties whereas males are more likely to externalize problems. There were no age differences associated with overall depression; however, there were some developmental differences in specific items cited. Finally, “red flags” were identified that may be helpful in spotting children suffering from severe levels of depression.     

Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

A Critique of Miller and Rohling's Statistical Interpretive Method for Neuropsychological Test Data

A critical review of the 24-step procedure of Miller and Rohling's (in press) proposed standardization of clinician's use of neuropsychological assessment batteries is presented. Each step is examined for statistical sources of invalidity. It was concluded that parts of the procedure are quite vulnerable to between-battery variability that cannot be easily estimated or controlled, leading to significant errors in analysis and classification. A second fatal flaw is the failure to distinguish in the procedures between standard error measurement and standard error of the estimate in calculations in several steps. The purpose of the process remains viable, however, and is an important contribution toward the improvement of clinical diagnosis.     

An exploratory study of cognitive style in performance on matched and mismatched tasks

Researchers have suggested that task performance is often dependent upon the congruence of cognitive style and task. To explore this suggestion, 44 female and 4 male undergraduates were administered the Cognitive Style Analysis, the Closure Flexibility, the Composite Gestalt Completion Test, and the Vocabulary subtest from the WAIS. Specifically, four hypotheses were tested: (1) that participants with an analytic style will perform better than those with a wholistic style on the Closure Flexibility; (2) that participants with a wholistic style will perform better than those with an analytic style on the Composite Gestalt Completion Test; (3) that participants with an intermediate style will outperform persons with an analytic style on the Composite Gestalt Completion Test; and (4) that intermediate scorers would perform better than those with a wholistic style on Closure Flexibility. Only the second hypothesis was supported, so results provide only minimal support for the effect of match or mismatch of cognitive style and task performance.     

Intellectual differences among Mexican Americans, Papagos and Whites, independent of g

Patterns of intellectual abilities for Mexican American and Native American Papago children were contrasted with those of White children, independent of overall differences in ability. Large differences in highly verbal skills remained, with Whites consistently outscoring the other two groups. Native Americans showed higher performance than Whites on spatial-visualization tasks but Mexican Americans exceeded Whites on no tasks. These race-related patterns of ability are nearly opposite those found in Black–White comparisons.     

Discrimination training facilitates pigeons' performance on one-trial-per-day delayed matching of key location

Six pigeons were tested on a one-trial-per-day variant of delayed matching of key location. In one condition, a trial began with the illumination of a pair of quasi-randomly selected pecking keys in a large 10-key test box. Pigeons' pecks to one key (the sample) were reinforced with 8-second access to grain on a variable-interval 30-second schedule, whereas pecks to the other key (the distractor) had no scheduled consequences. In the second condition, the nonreinforced distractor was not presented. In both conditions, subjects were removed from the apparatus after 15 minutes and placed in a holding cage. Subjects were subsequently replaced in the box after a delay (retention interval) of 30 seconds and were reexposed to the illuminated sample and distractor keys for 1 minute. If a pigeon made more pecks to the sample during this interval, the distractor was extinguished and subsequent pecks to the sample were reinforced on the previous schedule for an additional 15 minutes. If, however, a pigeon made more pecks to the distractor, both keys were extinguished and the subject was returned to its home cage. For all subjects, matching-to-sample accuracy was higher in the first condition. In a second experiment, the retention interval was increased to 5, 15, and 30 minutes, and then to 1, 2, 4, 8, 12, and 24 hours. Most subjects remembered the correct key location for up to 4 hours, and in one case, up to 24 hours, demonstrating a spatial-memory proficiency far better than previously reported in this species on delayed matching tasks. The results are discussed in terms of the commonly held distinction between working and reference memory.     

Gender vs. power: Self-posed behavior revisited

In an extended replication of Mills' (1984) study, equal numbers of male and female students in arts and science schools were photographed by a female undergraduate. Arts students, both male and female, displayed stereotypically female nonverbal behavior, i.e., smiling and head canting, but male undergraduates also canted their heads more than female undergraduates. Results were explained in terms of the meaning of these gestures and the arts/science effect interpreted as indicative of the greater power/esteem of the sciences. The findings also address wider issues of the meanings of non-verbal behavior.