Arithmetic based on the Church numerals in illative combinatory logic

In the early thirties, Church developed predicate calculus within a system based on lambda calculus. Rosser and Kleene developed Arithmetic within this system, but using a Godelization technique showed the system to be inconsistent.Alternative systems to that of Church have been developed, but so far more complex definitions of the natural numbers have had to be used. The present paper based on a system of illative combinatory logic developed previously by the author, does allow the use of the Church numerals. Given a new definition of equality all the Peano-type axioms of Mendelson except one can be derived. A rather weak extra axiom allows the proof of the remaining Peano axiom. Note. The illative combinatory logic used in this paper is similar to the logic employed in computer languages such as ML.The author wishes to thank Dr. Roger Hindley for proofreading this paper and for making some useful suggestions. This paper was presented at the 1986 Annual Conference of the Australasian Association of Logic in Auckland, 9–12 July, 1986.     

Perception of translational heading from optical flow

Radial patterns of optical flow produced by observer translation could be used to perceive the direction of self-movement during locomotion, and a number of formal analyses of such patterns have recently appeared. However, there is comparatively little empirical research on the perception of heading from optical flow, and what data there are indicate surprisingly poor performance, with heading errors on the order of 5 degrees-10 degrees. We examined heading judgments during translation parallel, perpendicular, and at oblique angles to a random-dot plane, varying observer speed and dot density. Using a discrimination task, we found that heading accuracy improved by an order of magnitude, with 75%-correct thresholds of 0.66 degrees in the highest speed and density condition and 1.2 degrees generally. Performance remained high with displays of 63-10 dots, but it dropped significantly with only 2 dots; there was no consistent speed effect and no effect of angle of approach to the surface. The results are inconsistent with theories based on the local focus of outflow, local motion parallax, multiple fixations, differential motion parallax, and the local maximum of divergence. But they are consistent with Gibson's (1950) original global radial outflow hypothesis for perception of heading during translation.     

Nonverbal communication as a compensative strategy for severely nonfluent aphasics? A quantitative approach

Seven severely nonfluent aphasics and one relative or close friend were investigated in an interview situation. The conversation was videotaped and analyzed for the use of nonverbal communication between aphasic and partner. The results indicate that the group of aphasics used significantly more frequently and for a significantly longer period of time nonverbal channels of communication than their healthy partners. The aphasic patients also used significantly fewer speech-focused movements and significantly more codified gestures. Nonverbal elements were more frequently used as speech substitutes by the group of aphasics.     

Effect of the interintromission interval on lordotic response and attack latency in golden hamsters (Mesocricetus auratus)

After 12-15 ejaculatory series, each consisting of several short intromissions (2- to 3-s vaginal penetration) and an ejaculation, male golden hamsters adopt an altered copulatory pattern consisting of long intromissions (5- to 25-s penetration with intravaginal thrusting). Receptivity declines and the tendency for the female to attack the male increases at about the time of this shift in copulatory pattern. Because the mean interintromission interval (III) between short intromissions is about 8 s compared to 100 s between long intromissions, it is possible that females detect this difference and adjust their mating accordingly. When the III between short intromissions from a rested male was experimentally increased to 100 s by use of a halter and lead device, the duration of lordosis was significantly less than that displayed by females paired with control males (8-s III) and virtually the same as that displayed by females paired with males that produced only long intromissions. This suggests that the female uses the temporal patterning of intravaginal stimulation as one criterion for terminating mating with a particular male.     

Confidence in judgments based on incomplete information: An investigation using both hypothetical and real gambles

This study assessed how confidence in judgments is affected by the need to make inferences about missing information. Subjects indicated their likelihood of taking each of a series of gambles based on both probability and payoff information or only one of these sources of information. They also rated their confidence in each likelihood judgment. Subjects in the Explicit Inference condition were asked to explicitly estimate the values of missing information before making their responses while subjects in the Implicit Inference condition were not. The manner in which probability information was framed was also manipulated. Experiment 1 employed hypothetical gambles and Experiment 2 employed gambles with real money. Expressed likelihood of taking gambles was higher when probability was phrased in terms of '% chance of winning' rather than '% chance of losing', but this difference was somewhat less with real gambles than with hypothetical gambles. Confidence ratings in each experiment were actually higher on incomplete information trials than on complete information trials in the Explicit Inference condition. Results were related to the general issue of confidence in judgments.     

An Assessment of the Job Relevance of the National Board for Certified Counselors Examination

The authors discuss the results of a study designed to assess nationally certified counselors' perceptions of the relevance of elements of the National Board for Certified Counselors examination to their work as counselors. Support for the validity and appropriateness of the examination in regard to perceived relevance and lack of differentiation on the basis of respondent characteristics were found.     

New Directions in Career Guidance: A Special Report for the Profession

Bonaparte, G., Chapman, J., & Steinberg, J. (1987). Michigan: Two career guidance models. Vocational Education Journal, 62(6), 142–143. Greenwood, K. (1987). Counseling adults in career transition. Vocational Education Journal, 62(6), 44–46. Herr, E.L. (1987). Comprehensive career guidance and vocational education: Natural allies. Vocational Education Journal, 62(6), 30–33. Lambert, R. (1987). A guide to career information. Vocational Education Journal, 62(6), 34–36. Lester, J.N., & McCormac, M.E. (1987). The NOICC career guidance standards project. Vocational Education Journal, 62(6), 47–48. Otto, L.B. (1987). Parents: Key advisors. Vocational Education Journal, 62(6), 37–38.     

Absence of age-related proneness to short-term retroactive interference in the absence of rehearsal

Age differences in short-term retroactive interference, unconfounded with age differences in rehearsal in the retention interval of the Brown-Peterson Task, were not found in a cross-sectional study of adults 18-32 and 64-78 years of age. Degree of retroactive interference was manipulated conjointly with distractor interval length (0-15 s). Individual memory span was assessed and used as the list length in order to achieve stimulus equivalence of memory loads across individuals and age groups. An attention-demanding matching task that adjusted itself in difficulty to the individual's attentional capacity was used as the distractor activity. Covert rehearsal during the retention interval was inferred using several measures, including a comparison of distractor task performance in the presence and in the absence of a memory load, and rehearsers were excluded from the primary analyses. We conclude that there is no interference proneness with increasing age in the present study.