Automatic and Controlled Processes in the Analytisis of Hierarchical Structure

Targets are identified faster if they appear at the same level (global vs. local) as the target on the previous trial. This effect has been attributed to a controlled attentional process wherein participants attend to the level containing the target on trial n − 1, thus facilitating performance if target level repeats on trial n. An alternative explanation (Lamb & Yund, 1966) is that automatic activation of level-specific neural mechanisms is responsible. The controlled-process hypothesis predicts better performance whenever target level is predictable, because participants can anticipate, and thus attend to, the appropriate level. The automatic-process hypothesis predicts better performance when target level repeats, regardless of target-level predictability. In the present studies, level repetitions facilitated performance regardless of target-level predictability. The data support the automatic-process explanation of level repetition and other attentional effects. The data illustrate how an automatic process can give rise to performance that seems to reflect more cognitive or strategic mechanisms.     

Importance of fathers' parenting to African-American toddler's social and cognitive development

The present study examined the degree to which parenting attitudes and behavior (i.e., self-reported warmth, restrictiveness, and behavioral sensitivity as assessed during a freeplay session) were related to toddlers' development. Results showed a restrictive attitude was negatively related to social and cognitive development, whereas paternal sensitivity was positively related to aspects of social development that are less dependent on language skills (e.g., motor and daily living skills). Fathers of girls exhibited greater sensitivity in their freeplay interactions than fathers of boys. More globally, the present research demonstrates important relations between the parenting attitudes and behavior of low- to working-income African-American fathers and young children's development, and similarities to White, middle-income fathers.     

Coding strategies,perceptual grouping,and the “variability effect” in free recall

Three experiments examined the effects of constant vs. varied input of letter strings on recall, and then examined the effects of such training in the learning of new lists of letter strings. Letter strings were constructed from pairs of trigrams spatially grouped, and were presented either consistently or with different spatial groupings on successive presentations. In Experiments I and II, varied input produced substantially greater recall than constant input. When transferred to a new list of letter strings, containing either the same general structure or a new scrambled structure, recall of the second list was determined primarily by conditions of first-list input, and unaffected by second-list structure. Although the "variability effect" did not appear in the training phase of Experiment III, Varied input led subjects to regroup or integrate the letter sequences more frequently and produced similar transfer effects as in Experiments I and II.     

On-line brain stimulation: Measurement of threshold of reinforcement

This program and interface for a small computer (PDP8/e) performs the following operations: generates and delivers constant current stimulation to the brain of an animal, monitors electrical resistance at the stimulating electrode, and calculates the threshold of reinforcement based upon the frequency of characteristic pauses in the animal’s responding.     

Stability of daily preference across multiple individuals

Preference stability provides clues about the extent to which a clinician might be able to deliver a particular stimulus contingent on behavior as a reinforcer. Previous research has been somewhat mixed in terms of evidence for preference stability. Results of the current study are consistent with studies that have reported correlations between preference assessments, suggesting that preferences are relatively stable across time.     

The Role of Non-Numerical Stimulus Features in Approximate Number System Training in Preschoolers from Low-Income Homes

Recent findings have suggested that adults’ and children’s approximate number system (ANS) acuity may be malleable through training, but research on ANS acuity has largely been conducted with adults and children who are from middle- to high-income homes. We conducted 2 experiments to test the malleability of ANS acuity in preschool-aged children from low-income homes and to test how non-numerical stimulus features affected performance. In Experiment 1, mixed-effects models indicated that children significantly improved their ratio achieved across training. Children’s change in probability of responding correctly across sessions was qualified by an interaction with surface area features of the arrays such that children improved their probability of answering correctly across sessions on trials in which numerosity conflicted with the total surface area of object sets significantly more than on trials in which total surface area positively correlated with numerosity. In Experiment 2, we found that children who completed ANS acuity training performed better on an ANS acuity task compared with children in a control group, but they only did so on ANS acuity trials in which numerosity conflicted with the total surface area of object sets. These findings suggest that training affects ANS acuity in children from low-income homes by fostering an ability to focus on numerosity in the face of conflicting non-numerical stimulus features.