Assessing early arithmetic abilities: Effects of verbal and nonverbal response types on the calculation performance of middle-and low-income children

In two studies, we compared young children's performance on three variations of a nonverbally presented calculation task. The experimental tasks used the same nonverbal mode of presentation but were varied according to response type: (1) putting out disks (nonverbal production); (2) choosing the correct number of disks from a multiple-choice array (nonverbal recognition); and (3) giving a number word (verbal production). The verbal production task required children to map numerosities onto the conventional number system while the nonverbal production and nonverbal recognition tasks did not. Study 1 showed that the performance of 3-, 4- and 5-year-old middle-income children (N = 72) did not vary with the type of response required. Children's answers to nonverbally presented addition and subtraction problems were available in both verbal and nonverbal forms. In contrast. Study 2 showed that low-income children (3- and 4-year-olds; N = 48) performed significantly better on both nonverbal response type tasks than on the verbal response type task. Analysis of individual data indicated that a number of the low-income children were successful on the completely nonverbal calculation tasks, even though they had difficulty with verbal counting (i.e., set enumeration and cardinality). The findings suggest that the ability to calculate does not depend on mastery of conventional symbols of arithmetic.     

Concept learning by pigeons: Matching-to-sample with trial-unique video picture stimuli

Pigeons were trained to match-to-sample with several new methodologies: a large number of stimuli, computer-drawn color picture stimuli, responses monitored by a computer touch screen, stimuli presented horizontally from the floor, and grain reinforcement delivered onto the picture stimuli. Following acquisition, matching-to-sample concept learning was assessed by transfer to novel stimuli on the first exposure to pairs of novel stimuli. One group (trial-unique), trained with 152 different pictures presented once daily, showed excellent transfer (80% correct). Transfer and baseline performances were equivalent, indicating that the matching-to-sample concept had been learned. A second group (2-stimulus), trained with only two different pictures, showed no evidence of transfer. These results are discussed in terms of the effect of numbers of exemplars on previous failures to find concept learning in pigeons, and the implications of the positive finding from this experiment on abstract concept learning and evolutionary cognitive development.     

Perseveration of associative strength in rabbit nictitating membrane response conditioning following ISI shifts

The present experiment determined whether associative strength based upon 15 CS-US pairings at various interstimulus intervals (ISIs) could survive shifts of the ISI to influence the subsequent acquisition of the nictitating membrane (NM) CR. The choice of 15 preshift pairings was based upon previous work, which had shown that this training level produced substantial associative strength without NM CR acquisition. Consequently, this experiment, by shifting the ISI before the beginning of CR acquisition, served as an extension to traditional ISI-shift studies that have imposed the manipulation after CR acquisition. The findings of the experiment indicated that 15 preshift pairings in Stage 1 at ISIs from 250 to 4,000 msec were as effective as 15 pairings at a 500-msec ISI in determining the number of trials to the first NM CR in Stage 2 in which the training ISI was 500 msec. Moreover, 15 pairings in Stage 1 at ISIs from 250 to 2,000 msec were equivalent to 15 pairings at 500 msec in controlling the number of trials to 10 successive NM CRs in Stage 2. These outcomes demonstrate that, within a large ISI range, the associative strength based upon relatively few pairings is preserved despite various shifts of the ISI. Therefore, these results suggest that the reductions in CR performance, which have been consistently observed in traditional studies following ISI shifts, are not due to the loss of associative strength.     

Genetic influences in different aspects of language development: the etiology of language skills in 4.5-year-old twins

The genetic and environmental etiologies of diverse aspects of language ability and disability, including articulation, phonology, grammar, vocabulary, and verbal memory, were investigated in a U.K. sample of 787 pairs of 4.5-year-old same-sex and opposite-sex twins. Moderate genetic influence was found for all aspects of language in the normal range. A similar pattern was found at the low end of the distribution with the exception of two receptive measures. Environmental influence was mainly due to nonshared factors, unique to the individual, with little influence from shared environment for most measures. Genetic and environmental influences on language ability and disability are quantitatively and qualitatively similar for males and females.     

Certainty of Punishment and Criminal Thinking: Do the Rational and Non-rational Parameters of a Student’s Decision to Cheat on an Exam Interact?

The purpose of this study was to determine whether criminal thinking interacts with the rational requirements of human decision-making in a group of college students. A convenience sample of 315 undergraduates (114 males, 201 females) completed self-report measures of criminal thinking and estimated their likelihood of cheating on an exam given different levels of certainty of apprehension. A repeated-measures analysis of covariance revealed that students were significantly more likely to seize on the opportunity to cheat when the certainty of getting caught was 10% than when it was 50% and that students with higher levels of criminal thinking were more likely to take the opportunity to cheat than students with lower levels of criminal thinking. In addition, students exhibiting moderate proactive criminal thinking and moderate to high reactive criminal thinking were significantly less likely to be deterred from cheating when the odds of getting caught were low.     

Adjunctive drinking during variable and random-interval food reinforcement schedules

Rats were trained to leverpress for food and subsequently exposed to either arithmetic series or random variable-interval reinforcement schedules. Adjunctive drinking developed in all subjects exposed to arithmetic variable-interval reinforcement, but did not develop in six of the eight animals trained on the random schedule. The results suggest that adjunctive drinking is the result of an interaction between the tendency of rats to drink after eating and the ability of locally low probabilities of reinforcement within schedules to induce conditioned behavioral states.