Preschoolers’ nonsymbolic arithmetic with large sets: Is addition more accurate than subtraction?

Adult and developing humans share with other animals analog magnitude representations of number that support nonsymbolic arithmetic with large sets. This experiment tested the hypothesis that such representations may be more accurate for addition than for subtraction in children as young as 3½ years of age. In these tasks, the experimenter hid two equal sets of cookies, visibly added to or subtracted from the sets, and then asked 3½-year-olds which set had more cookies. Initial set size was either large (7 or 9) or very large (18 or 30), and the final sets differed by either a high proportion (ratio of 1:2) or a low proportion (difference of 1 cookie). Children’s addition performance exceeded chance, as well as their subtraction performance, across set sizes and proportions, whereas subtraction performance did not exceed chance. Arithmetic performance was also independent of counting ability. Addition performance was remarkably accurate when ratios between outcomes were close to 1, in contrast to previous findings. Interpretations for the asymmetry between addition and subtraction are discussed with respect to the nature of representations for nonsymbolic arithmetic with large sets.     

A method for the delivery of reinforcement during exercise

The purpose of this study was to develop an automated system for positively or negatively reinforcing subjects while they exercised on an electronically braked bicycle ergometer. The circuitry used to interface the subject’s pedal speed responses with the delivery of auditory reinforcement is presented, as well as a study designed to test the utility of the system. Twenty 18- to 25-year-old male subjects exercised on an electronically braked ergometer at a constant workload of 50 W for three 5-min blocks. During the first 5 min, subjects pedaled at their preferred rate, and during the next two 5-min blocks, they pedaled faster or slower than their baseline pedal speed to turn on a comedy tape for positive reinforcement, or turn off 90 dB of white noise for negative reinforcement. Circuits that interfaced the subject’s pedal response with the delivery of reinforcement are discussed in detail. Both positive and negative reinforcement increased the targeted pedaling rates, with no differences as a function of targeting increased or decreased pedal speed. This system could be used with various reinforcers, such as video and other audio equipment to increase exercise behavior.     

Difference without dominance: Children's talk in mixed- and same-sex dyads

This study explores whether third graders verbalize gender differences in dominance in mixed- and same-sex interaction. We tape-recorded the conversations of 43 pairs of Caucasian working-class children playing checkers in same- or mixed-sex conditions. Children appear to develop gender-differentiated speech styles. Boys brag and insult their opponents in both mixed- and same-sex conditions more often than do girls. Girls talk off-topic, interrupt, and laugh more in same-sex dyads than do boys or either, boys or girls in mixed-sex dyads. Gender differences in same-sex interaction were reflected in mixed-sex interaction. Although boys account for a larger proportion of direct requests and self-promoting speech in mixed-sex encounters, we failed to uncover substantial asymmetry in mixed-sex interaction, indicating that boys do not conversationally dominate girls in third grade. However, children were less mutually engaged in mixed-sex than in same-sex interactions, and girls especially showed less positive affect in mixed-sex dyads.     

An empirical update (1969-1989) of D. L. Krantz's thesis that the experimental analysis of behavior is isolated

Citation data from 1970 to 1989 were examined in order to determine whether the "isolation" of the experimental analysis of behavior (EAB) that was originally documented by Krantz (1971, 1972) has persisted beyond the early 1970s. Our findings from analyses of the Journal of the Experimental Analysis of Behavior (JEAB) and of related journals support the following conclusions: (1) In the 20-year period since 1969, JEAB has continued to cite its own articles ("self-cite") at a higher rate than related journals; (2) JEAB's self-citation rate decreased by a larger amount since 1969 than did that of related journals; and (3) JEAB was cited with diminishing frequency by some related journals during the 20-year period. These findings and other disciplinary comparisons provide information relevant to the issue of the health of behavior analysis and related specialties.     

Implications of placebo theory for clinical research and practice in pain management

We review three possible theoretical mechanisms for the placebo effect: conditioning, expectancy and endogenous opiates and consider the implications of the first two for clinical research and practice in the area of pain management. Methodological issues in the use of placebos as controls are discussed and include subtractive versus additive expectancy effects, no treatment controls, active placebo controls, the balanced placebo design, between- versus within-group designs, triple blind methodology and the double expectancy design. Therapeutically, the possibility of shaping negative placebo responses through placebo sag, overservicing and the use of placebos on their own are explored. Suggestions for using conditioned placebos strategically in conjunction with nonplacebos are made and ways of maximizing the placebo component of nonplacebo treatments are examined. Finally, the importance of investigating the placebo effect in its own right is advocated in order to better understand the long-neglected psychological aspects of the therapeutic transaction.     

Consequences of response-contingent change in unconditioned stimulus intensity upon the rabbit (Oryctolagus cuniculus) nictitating membrane response.

In a between-groups design, an instrumental contingency was superimposed on classical conditioning of the rabbit nictitating membrane response. Subjects were exposed to a tonal conditioned stimulus (CS) and, if no conditioned response (CR) occurred, a 5.0-ma. paraorbital electric shock unconditioned stimulus (US). USs of 5.0, 3.3, 1.7, and 0.0 ma., respectively, were contingent on occurrence of a CR in the CS-US interval for subjects in the 4 groups of the experiment. The group exposed to contingent US omission differed from the other 3 groups in percentage CR, onset latency, amplitude, and 2 indices of CR form, and those 3 groups generally did not differ significantly among themselves on these dependent variables. Results were interpreted to be contrary to "law of effect" formulations of classical conditioning.