Developmental seizures induced by common early-life insults: short- and long-term effects on seizure susceptibility

The immature brain is highly susceptible to seizures induced by a variety of insults, including hypoxia, fever, and trauma. Unlike early life epilepsy associated with congenital dysplasias or genetic abnormalities, insults induce a hyperexcitable state in a previously normal brain. Here we evaluate the epileptogenic effects of seizure-inducing stimuli on the developing brain, and the age and regional specificity of these effects.     

Assessing individual differences: effects of responding to prior questionnaires on the substantive and psychometric properties of self-esteem and depression assessments

It has become a common practice among psychological researchers to administer batteries of individual difference assessments to research participants, although little is known about whether the substantive and psychometric integrity of the questionnaires are maintained when they are administered after the subject has completed other instruments. The studies presented here consider these issues in relation to the assessment of self-esteem and depression. In the first study, college students responded to a self-esteem inventory (a) by itself (control group), (b) after one prior questionnaire, (c) after three prior questionnaires, or (d) after five prior questionnaires. Results indicated that filling out one or more questionnaires before an assessment of self-esteem resulted in reports of lower self-esteem relative to the control condition. Additional analyses revealed that filling out three or five prior questionnaires created lower reliabilities of subscale scores and lower estimates of concurrent validity between self-esteem and depression. When the effect of prior questionnaires on the General Self-Esteem subscale was examined, the aforementioned results were replicated, and the prior questionnaire treatment created heterogeneous variances across the experimental groups. The second study was designed as a replication of the first study, using an assessment of depression as the target questionnaire. These results revealed that reports of depressive symptomatology increased as the number of prior questionnaires increased. Again, the prior questionnaire treatment created heterogeneity of variance between the groups, but did not adversely affect its internal consistency.     

Equivalence classes generated by sequence training

In Experiment 1, 3, adult females were taught with verbal instructions and contingencies to select, in sequence, three arbitrary visual stimuli from an array of five stimuli. After four different sequences were taught, match-to-sample tests assessed emergent conditional relations among all stimuli that had been selected in the same order in the sequences. Subjects' performances indicated development of four stimulus classes, three based on ordinal position and one based on nonselection. Next, match-to-sample training established conditional relations between each of four novel figures and one member of each of the ordinal stimulus classes. Tests confirmed that the classes were equivalence classes, each expanded by one new member. In subsequent sequence tests, the new stimuli were selected in a sequence that was consistent with ordinal class membership. Experiment 2 replicated Experiment 1 with 2 different adult females, but the verbal instructions were omitted. Results were similar to Experiment 1, except that extensive review and retesting were required before expansion of the ordinal classes with the novel figures was observed.     

Auditory psychomotor coordination and visual search performance

In Experiments 1 and 2, the time to locate and identify a visual target (visual search performance in a two-alternative forced-choice paradigm) was measured as a function of the location of the target relative to the subject's initial line of gaze. In Experiment 1, tests were conducted within a 260 degree region on the horizontal plane at a fixed elevation (eye level). In Experiment 2, the position of the target was varied in both the horizontal (260 degrees) and the vertical (+/- 46 degrees from the initial line of gaze) planes. In both experiments, and for all locations tested, the time required to conduct a visual search was reduced substantially (175-1,200 msec) when a 10-Hz click train was presented from the same location as that occupied by the visual target. Significant differences in latencies were still evident when the visual target was located within 10 degrees of the initial line of gaze (central visual field). In Experiment 3, we examined head and eye movements that occur as subjects attempt to locate a sound source. Concurrent movements of the head and eyes are commonly encountered during auditorily directed search behavior. In over half of the trials, eyelid closures were apparent as the subjects attempted to orient themselves toward the sound source. The results from these experiments support the hypothesis that the auditory spatial channel has a significant role in regulating visual gaze.     

Differential use of distance and location information for spatial localization

Five experiments are reported in which subjects judged the movement or spatial location of a visible object that underwent a combination of real and induced (illusory) motion. When subjects attempted to reproduce the distance that the object moved by moving their unseen hands, they were more affected by the illusion than when they pointed to the object's perceived final location. Furthermore, pointing to the final location was more affected by the illusion when the hand movement began from the same position as that at which the object initially appeared, as compared with responses that began from other positions. The results suggest that people may separately encode two distinct types of spatial information: (1) information about the distance moved by an object and (2) information about the absolute spatial location of the object. Information about distance is more susceptible to the influence of an induced motion illusion, and people appear to rely differentially on the different types of spatial information, depending on features of the pointing response. The results have important implications for the mechanisms that underlie spatially oriented behavior in general.     

Race and brain weight: a note on J.P. Rushton's conclusions

Rushton's (1988) reinterpretation of recent research on brain weight one-sidedly emphasizes the findings of heavier brain weight in whites than in blacks and neglects to comment on a larger difference found between men and women. Rushton explicitly used brain size as indicator of intelligence. His implicit conclusion that women are less intelligent than men is not supported by empirical research.     

Evaluation of subclinical depression in children using self-, peer-, and teacher-report measures

This study reports on several classification issues utilizing the Children's Depression Inventory (CDI), the Child Behavior Checklist-Teacher Form (CBCL-T), and the Peer Nomination Inventory of Depression (PNID). The first sample contained 752 public school children in grades 5, 6, and 9. A second sample of 142 fifth-graders was included to have an additional PNID comparison group. Results revealed moderate correlations between the CDI and the CBCL-T and PNID. Use of multiple criteria for selecting children as depressed was discussed, and selection rates using multiple measures with either strict or lenient cutoff scores were given. Normative data on the PNID were evaluated, and it was suggested that norms for the PNID may not be generalizable to other samples. Finally, race and gender analyses showed that CDI scores for females were significantly higher than for males, whereas CDI scores for Hispanics were significantly higher than for non-Hispanic whites. However, Omega-squared analyses for these two variables showed this to be of little practical significance.     

The revelation effect: when disguising test items induces recognition

Documented here is a bias whereby items are more likely to be judged as having been presented beforehand if they are disguised in some way and so have to be discovered or "revealed." The bias was found for test words that were unfolded letter by letter (Experiments 1 and 3), presented with their letters either transposed (Experiments 2 and 3), or individually rotated (Experiments 4 and 5), or rotated as a whole (Experiment 5), and for test numbers that were presented in the form of roman numerals (Experiment 6) or equations (Experiment 7). The bias occurred both for items that were presented beforehand and for those that were not. No bias was found when words were judged, not for prior occurrence, but for typicality as category instances (Experiment 8), lexicality (Experiment 9), frequency of general usage (Experiment 10), or number of times encountered during the preceding week (Experiment 11).     

Use of case vignettes in suicide risk assessment

Thirty-three brief case histories of suicidal patients were given to 19 experienced crisis workers for 7-point ratings of short- and long-term suicide risk. The ratings revealed considerable variability, raising questions about the reliability of such global assessments of suicidality. The most consistently rated cases were selected to operationally define "mild," "moderate," and "high" risk. Thus, each level was "anchored" by several vignettes. It was hoped that these anchor points would lead to more uniform future ratings among crisis workers. The correlation between short- and long-term risk ranged from near zero for some vignettes to as high as .82 (median = .46), demonstrating the need to rate both separately. Long-term risk was more difficult to rate, as demonstrated by a larger number of cases judged to be unrateable because of "insufficient information" (94 vs. 53 rater-case combinations). When the anchor vignettes were provided as a guide to the same sample of crisis workers, their ratings of suicide risk, as expected, showed significantly improved consistency.