Dynamic equilibrium on a cyclic-interval schedule with a ramp

Five human subjects pressed a panel for money on a cyclic-interval schedule that arranged recurring periods of linearly increasing reinforcement rates (ramps). Response rate versus time functions for all subjects showed recurring periods of linearly increasing response rates. The responding of four of the five subjects was in phase with the reinforcement input. The remaining subject showed a two-minute phase shift. These results suggest that organisms may act like simple amplifiers on cyclic-interval schedules, that is, the form of the input signal is not changed by the organism, but is returned with amplification. By analogy with the variable-interval case, the controlling variable on cyclic-interval schedules with rate ramps may be the constant reinforcement acceleration that is arranged by the schedule.     

Visual‐motor and executive functions in children born preterm: The Bender Visual Motor Gestalt Test revisited

Böhm, B., Lundequist, A. & Smedler, A.‐C. (2010). Visual‐motor and executive functions in children born preterm: The Bender Visual Motor Gestalt Test revisited. Scandinavian Journal of Psychology, 51, 376–384. Visual‐motor development and executive functions were investigated with the Bender Test at age 5½ years in 175 children born preterm and 125 full‐term controls, within the longitudinal Stockholm Neonatal Project. Assessment also included WPPSI‐R and NEPSY neuropsychological battery for ages 4–7 ( Korkman, 1990 ). Bender protocols were scored according to Brannigan & Decker (2003) , Koppitz (1963) and a complementary neuropsychological scoring system (ABC), aimed at executive functions and developed for this study. Bender results by all three scoring systems were strongly related to overall cognitive level (Performance IQ), in both groups. The preterm group displayed inferior visual‐motor skills compared to controls also when controlling for IQ. The largest group differences were found on the ABC scoring, which shared unique variance with NEPSY tests of executive function. Multiple regression analyses showed that hyperactive behavior and inattention increased the risk for visual‐motor deficits in children born preterm, whereas no added risk was seen among hyperactive term children. Gender differences favoring girls were strongest within the preterm group, presumably reflecting the specific vulnerability of preterm boys. The results indicate that preterm children develop a different neurobehavioral organization from children born at term, and that the Bender test with a neuropsychological scoring is a useful tool in developmental screening around school start.