We propose a simple computational model that describes potential mechanisms underlying the organization and development of the lexical-semantic system in 18-month-old infants. We focus on two independent aspects: (i) on potential mechanisms underlying the development of taxonomic and associative priming, and (ii) on potential mechanisms underlying…

The aim of this study was to model a situation that induced choice between following two incompatible rules, each associated with a different rate of reinforcement. In Experiment 1, eight undergraduate students were exposed to a two-component multiple schedule (training). In each component, there was a concurrent variable interval (VI)-extinction…

Cognitive control theories describe the active maintenance of goal representations over temporal delays as central for adaptive behavior. Dynamic adaptations of goal representations are often measured as the congruency sequence effect (CSE), which describes a reduced congruency effect in trials following incongruent trials compared to congruent…

Eyeblink conditioning is used in many species to study motor learning and make inferences about cerebellar function. However, the discrepancies in performance between humans and other species combined with evidence that volition and awareness can modulate learning suggest that eyeblink conditioning is not merely a passive form of learning that…

A cognitive-energetic account of individual differences in working memory capacity (WMC) and sustained attention performance is proposed suggesting that variation in the voluntary control of the intensity of attention (intrinsic alertness) is critical for the relation between WMC and attention control. Four experiments examining individual…

What can we learn from a pause? This dissertation examines whether a pause between speaking turns in a conversation (a gap) can change how we view that conversation and its participants (a gap effect). In particular, it asks whether the length of a gap can influence interactional attributions--that is, attributions of the participants' engagement…

Purpose: The present study examined whether engaging working memory in a secondary task benefits speech fluency. Effects of dual-task conditions on speech fluency, rate, and errors were examined with respect to predictions derived from three related theoretical accounts of disfluencies. Method: Nineteen adults who stutter and twenty adults who do…

Stimulus-stimulus pairing (SSP) of vocalizations pairs the speech of others with the delivery of highly preferred items. The goal of this procedure is to produce a temporary increase in vocalizations, thus creating a larger variety of sounds that can subsequently be brought under appropriate stimulus control (Esch, Carr, & Grow, 2009). In this…

The force-frequency relationship has intrigued researchers since its discovery by Bowditch in 1871. Many attempts have been made to construct mathematical descriptions of this phenomenon, beginning with the simple formulation of Koch-Wesser and Blinks in 1963 to the most sophisticated ones of today. This property of cardiac muscle is amplified by…

In conditioned taste aversion (CTA), a taste, the conditioned stimulus (CS), is paired with an illness-inducing stimulus, the unconditioned stimulus (US), to produce CS-US associations at very long (hours) intervals, a result that appears to violate the law of contiguity. The specific length of the maximum effective trace interval that has been…

Pigeons trained on successive AB symbolic matching show emergent BA antisymmetry if they are also trained on successive AA oddity and BB identity (Urcuioli, 2008, Experiment 4). In other words, when tested on BA probe trials following training, they respond more to the comparisons on the reverse of the nonreinforced AB baseline trials than on the…

According to the hypothesis of a scalar property for time, the variability to time ratio should be constant. Three experiments tested the validity of this hypothesis in a restricted range of durations (standard values = 1, 1.3, 1.6, and 1.9 s). In each experiment, time intervals to be discriminated, reproduced, or categorized were presented with…

Stimulus over-selectivity occurs when one aspect of the environment controls behavior at the expense of other equally salient aspects. Participants were trained on a match-to-sample (MTS) discrimination task. Levels of over-selectivity in a group of children (4-18 years) with Autism Spectrum Disorders (ASD) were compared with a mental-aged matched…

We evaluated the effects of different intertrial intervals (ITIs; time between programmed learning opportunities) on the acquisition and generalization of 2 preschoolers' social skills. Independent and generalized skills were observed only when the daily ITI was gradually increased from short to progressively longer intervals. (Contains 1 figure…

Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In…