Parallel distributed processing and neuropsychology: A neural network model of Wisconsin card sorting and verbal fluency

Neural networks can be used as a tool in the explanation of neuropsychological data. Using the Hebbian Learning Rule and other such principles as competition and modifiable interlevel feedback, researchers have successfully modeled a widely used neuropsychological test, the Wisconsin Card Sorting Test. One of these models is reviewed here and extended to a qualitative analysis of how verbal fluency might be modeled, which demonstrates the importance of accounting for the attentional components of both tests. Difficulties remain in programming sequential cognitive processes within a parallel distributed processing (PDP) framework and integrating exceedingly complex neuropsychological tests such as Proverbs. PDP neural network methodology offers neuropsychologists co-validation procedures within narrowly defined areas of reliability and validity.     

The real and the ideal; gender differences in heterosexual behaviour among Norwegian adolescents

This article focuses on gender differences in early heterosexual behaviour among Norwegian adolescents. The material comprised a random sample of 3000 Norwegian adolescents aged 17–19 years. The response rate was 63%. Data were collected by means of anonymous self-administered questionnaires. Sixty-nine per cent of the girls and 59% of the boys had had sexual intercourse. The majority of the adolescents, and a larger percentage of girls than of boys, had their first intercourse within a relationship of mutual commitment. The boys' first coital partners were 0.2 years younger than the boys themselves and the girls' partners were 2.8 years older than were the girls. Boys had had more coital partners than girls but girls had had intercourse more often than boys. Coital frequency was affected more by how long the adolescents had known the partner than by gender as such. In conclusion, boys and girls aged between 17 and 19 years form part of couples at two different stages of development. For this reason, boys and girls accumulate different sexual experiences in the early stage of their sexual careers.     

Motion coherence and conjunction search: Implications for guided search theory

Feature integration theory has recently been revised with two proposals that visual conjunction search can be parallel under some circumstances—either because items with nontarget features are inhibited, or because items with target features are excited. We examined whether excitatory or inhibitory guidance controlled conjunction search for an X oscillating in one direction among Os oscillating in that direction and Xs oscillating in another. Search was affected by whether items oscillated in phase with each other, and it was exceptionally difficult when items with target motion moved out of phase with each otherand items with nontarget motion moved out of phase. The results suggest that conjunction search can be guided both by excitation of target features and by inhibition of nontarget features.     

PROMOTING SAFETY BELT USE WITH TRAFFIC SIGNS AND PROMPTERS

Two studies were conducted examining the stimulus-control effects of conventional traffic signs as prompts for motor vehicle driver safety belt use. Following pilot research which suggested that a traffic sign reading “Fasten Safety Belt” posted at a parking lot exit was effective in producing small increases in safety belt use, Study I demonstrated the superiority of having human prompters display such signs compared to simply posting the signs. Study II replicated the findings of Study I and found that posted signs became more effective in prompting safety belt use if simple posting was preceded by a period involving human prompters who displayed the signs. The results bear upon the development of more effective use of traffic signs in promoting safety belt use and in viewing such use as an instance of rule-governed behavior.     

PROMOTING AUTOMOBILE SAFETY BELT USE BY YOUNG CHILDREN

A program using behavioral practice, assertiveness training, and social and contrived reinforcers was developed to establish and maintain automobile safety belt use by young children. Sixteen children (ages 4.8 to 7 years) who never used their safety belts during a 5-day preexperimental observation period were randomly assigned to two groups of eight each. A multiple baseline design across groups was used to evaluate the effectiveness of the training program. During the 8-day baseline period for Group 1, no children used their safety belts when unobtrusively observed while being driven from school. During the 26-day intervention period, the children were buckled up on 96% of the observations. Follow-up probes conducted 2–3 months after program discontinuance found safety belt use to range from 86% to 100%. For Group 2, the 14-day baseline safety belt use averaged 6% and increased to a mean of 81% during the 20-day training and maintenance program. Follow-up probes 2–3 months later found safety belt use to occur during 75% to 96% of the observations. Parent questionnaires indicated the generalizability and social validity of the program.     

INCREASING APPOINTMENT KEEPING BY REDUCING THE CALL-APPOINTMENT INTERVAL

We examined the effect of reducing the interval between a patient's call for an appointment and the appointment itself. In Experiment 1, patients calling a family planning unit of a public health department were assigned appointments within either 1 or 3 weeks of their call. Data on patient “shows” and “no-shows” were recorded weekly for 6 weeks. Show rates for those in the 1-week appointment group were significantly higher than those in the 3-week group. In Experiment 2, patients were assigned to appointment dates either the next operating clinic day (next-day group) or 2 weeks from the call date (2-week group). Show rates for those in the next-day group were significantly better than show rates for patients in the 2-week group. Clinic productivity, time spent with patients, and consumer satisfaction were also assessed. Implications for appointment scheduling are discussed.     

Belief in afterlife as a moderator of fear of death?

Investigating the notion that belief in afrerlife (BA) serves the function of helping the individual to deal with fear of death, a study was designed to explore the effect of public commitment to religion, repression-sensitization, and anticipatory concern with death and dying on BA, and examine the relationship between BA and state anxiety. Fifty students of theology and fifty students of various other subjects responded to a German version of Byrne's R-S scale, and then were randomly assigned to two conditions: they either worked through Thanatos-Questionnaire, and thereby were confronted with death and dying for about 15 to 20 minutes, or filled out a questionnaire unrelated to the topic. Thereupon, a BA scale was administered, and at last, subjects responded to a scale measuring state anxiety. The findings of Osarchuk and Tatz (1973) that religiously committed persons are strengthening BA after being confronted with death and dying could not be replicated. However, among subjects with no public commitment, those concerned with death and dying scored significantly lower on BA than those not concerned. This effect was especially observed among students classified as sensitizers. Because changes of BA did not correspond with changes of within cell correlations between BA and state anxiety, an alternative explanation of the findings in terms of dissonance theory is put forward.     

Factors limiting the generality of the risky-shift phenomenon

While a considerable amount of research has centered on explaining the risky shift (enhancement of risk acceptance through group discussion; see, for example, Dion, Baron, and Miller, 1970), few studies have investigated the generality of the phenomenon. Three of several ways in which the laboratory context is usually lacking of reality are: (a) The decision consequences are imaginary, as in the ‘Choice-Dilemma’ situations used in most of the risky-shift research; (b) the decision consequences - even if they are real (e.g. money) - are slight; and (c) the decisions are made for oneself (whereas in real life many decisions involve agents acting on behalf of others). The present study was designed to investigate the effects of the above three factors - type of incentive, magnitude of stake and decision target - using a betting task as the decision situation.     

Two types of short-term visual storage

Seven-letter words were flashed repetitively at various durations above and below the recognition threshold for single flashes. One form of a short-term storage effect was studied by measuring the interstimulus interval between flashes at which S reported that the stimulus became phenomenally discontinuous in time. Storage times reached a maximum of about 300 msec in this task. A second form of storage effect was measured by decreasing the interstimulus interval until S could correctly recognize a repeated stimulus whose duration was below the single-flash recognition threshold; this effect extended to 900 msec in some cases. Each of these effects was reliably obtained for both rare and frequent words. Both forms of storage were increased by providing a dark rather than a lighted adapting field between presentations of the test stimulus. Implications for Information processing of brief displays are discussed.