Saccade latency and warning signals: Stimulus onset,offset, and change as warning events

Two experiments investigated saccade latency to a peripheral target under various warning signal conditions. In Experiment I, the effects of warning stimulus onset, change, and two offset conditions were compared at warning intervals of 0, 100, 300, and 600 msec. Warning stimulus onset, change, and offset were all effective in reducing saccade latency as compared to a no-warning control condition, but warning stimulus offset resulted in shorter saccade latency than onset or change at all warning intervals. Experiment 2 compared onset and offset warning conditions at ?300-, ?250-, ?200-, ?150-, ?100-, ?50-, 0-, and 50-msec intervals. Responses following onset were slower than those following offset at the latter five intervals, while warning onset resulted in slower saccades than no-warning control conditions at ?150-, ?100-, and ?50-msec intervals. These results indicate that the onset of a visual warning signal can have an interfering effect on the programming or execution of a saccade.     

APL functions for interactive data analysis: Graphics and labels

APL functions designed to provide labeled plots and histograms are described. Support functions that augment a data file with necessary information to label output and to maintain a common plotting scale are also described. APL code and illustrative output are presented.     

Some psychological correlates of generalized and focal epilepsy in children

School-aged children with two types of epilepsy, generalized and focal, were compared with normal children of the same age, sex, and IQ on measures of cognitive style, attention, motor control, and behavioral pathology. Epileptic children were found to employ less efficient cognitive strategies and to have longer reaction times and poorer control of fine motor movements than have normal children. Children with generalized epilepsy were more impaired than were normal children when sustained motor performance was required. Mothers of children with generalized epilepsy reported more behavior problems than did control mothers on an objective checklist. These results suggest special educational methods for the treatment and education of epileptic children.The research reported in this paper was supported by Grant No. MA-45O5 from the Medical Research Council of Canada. Grateful thanks are extended to Dr. Katherine Metrakos, Director of the Convulsive Disorder Clinic, Montreal Children's Hospital, who screened epileptic subjects and gave us her enthusiastic support. The Diagnostic Test Center was most helpful in providing blood serum levels on the clinical sample. We wish to thank the Notre Dame de Grace and Westmount branches of the Y.M.C.A. for access to control subjects.     

Syntactic complexity and information transmission in first-graders: A cross-cultural study

Some differences between child and adult communication are due to general developmental immaturity and some to language-specific factors. The Piagetan concept of syncretism exemplifies an hypothecated universal of psycholinguistic development, and it results in child texts characterized by minimally structured temporal, causal, and logical connections. A different sort of problem is that, within a specific language, certain syntactic items may fail to mature in children at the expected rate, because of structural oddities of the constructions. English has several such constructions, generally peculiar in their conflict between surface- and deep-structure subject of the main verb. It is predictable that a syncretistic child attempting to deal with such items in a text will analyze them according to the surface-structure analogic method which defines verbal syncretism, and so will fail to make sense of them. Finally, cutting across these child language features are others peculiar to the language of specific groups of children, such as the putative communication impairment of the disadvantaged black child, whose language has been described by some researchers as less efficient and slower to mature than that of others. Clearly, if this is so, then black children's language should at any young age show more evidence of syncretistic communicative immaturity as well as slower development of adult syntactic patterns. The present paper, then, investigates on a cross-cultural basis the dual hypotheses of syncretism and faulty mastery of difficult syntax, by means of an experimental story-repeating format first used by Piaget. Hypotheses are examined for the cause of children's distinctive communication technique, and the whole question of the significance of black/white differences in communicative style and verbal maturity is discussed.     

Some implications for psychological research of early versus late term participation by college subjects

Several surveys of recent psychological literature have indicated that a large percentage of human subjects are introductory psychology students who are given the option of selecting when to participate in research which is either implicitly or explicitly required of them. The present study was conducted to investigate the possibility that those subjects who choose to participate early in the term differ in personality and in attitudes toward research from later term participants. Results indicated that early term males and females, as expected, were more academically oriented and more internally controlled than late term subjects; and early term males were more achievement oriented than their late term counterparts. Additionally, females were found to feel more positive toward research participation than males; while a large percentage of all subjects reported both suspiciousness of experimenter intent and a general and unexpected willingness to voluntarily participate as subjects. Possible effects of these findings on research results and conclusions were discussed, and suggestions for improvements aimed at reducing self-selection bias in college subject pools were made.     

Position constancy and binocular convergence

The position constancy during head movement of a luminous spot in a dark room depends in part on the convergence state of the eyes. This supports a modified form of the theory that an optical-motion/head-motion comparator contributes to constancy. By incorporating convergence information, the comparator can allow [or the effect of parallax on the optical-motion/body-motion ratio.     

The Junior College Student

Using data obtained by Project TALENT, a nationwide study of high school youth, the authors describe the junior college student. The junior college, non-college, and college students have been compared along six measures of information and eight of general aptitude and ability. Through the use of a six-group discriminant analysis, it was found that junior college students have a tendency to be more like non-college students in terms of ability. However, sex differences on the ability measures were greater than the differences among the three college-planning groups. Although the junior college student looks more like the non-college student in terms of ability, he appears to be more like the college student in terms of socio-economic factors.