Noticing and responding in a discrimination based on a distinguishing element

In learning a successive go/no-go discrimination between a positive display consisting of the elements A and B, and negative display consisting of A-alone, pigeons first trained to peck A shift to pecking the distinguishing B element. In order to learn whether or not the shift to B is facilitated by B's function as a signal of the reinforcer, apart from the direct reinforcement of B responses, six arrangements of the elements with respect to the food reinforcer were used. Discrete trials were terminated by a single peck or after 4 sec. The A and B elements were dots of different color. The most critical comparison was between two groups, both of which received no reinforcement for a response directed to B. In one case, B signaled the reinforcer: An A response was reinforced when B was present but not when A appeared alone. In the other, B signaled the absence of a reinforcer: An A response was nonreinforced when B was present, while the response to A-alone was reinforced. During training and in extinction many more reponses were made to B when it signaled the reinforcer than when it signaled its absence. It is concluded that in a discrimination between AB positive and A negative the shift from pecking A to pecking B is facilitated by B's role as a signal for the reinforcer even on trials in which the peck is not made to B. Results from certain other groups showed that, unless pecks shifted to B within the positive display, pecks to A continued on the negative, A-alone trials as well as on the positive AB trials.     

Pregnancy hypertension and the risk for neuropsychological difficulties across early development: A brief report

Despite documented effects on fetal brain development, little is currently known about the relationship between maternal pregnancy hypertension and child neuropsychological outcomes. This brief report examined the association between maternal hypertension during pregnancy and children’s social cognition and executive functioning when children were 18 months, 3 years, and 4.5 years. A community sample of 501 families (23 hypertensive mothers; 478 nonhypertensive) was recruited when children were newborns. Social cognition (including theory of mind [ToM]) and executive functioning (EF) were measured using a battery of age-appropriate standardized and/or observational tasks. Information on pregnancy and prenatal factors were measured via maternal report when children were newborns. After controlling for prenatal and demographic covariates, the presence of hypertension difficulties during pregnancy was associated with all measures of social cognition, ToM, and EF. A secondary analysis comparing the hypertension group (n = 23) to a nonhypertensive matched control group (n = 23) supported the effect of pregnancy hypertension on children’s social-cognitive and EF development. Future studies using obstetrical records are encouraged based on these preliminary findings.