Pigeons encode absolute distance but relational direction from landmarks and walls

In recent studies, researchers have examined animals' use of absolute or relational distances in finding a hidden goal. When trained with an array of landmarks, most animals use the default strategy of searching at an absolute distance from 1 or more landmarks. In contrast, when trained in enclosures, animals often use the relationship among walls. In the present study, pigeons were trained to find the center of an array of landmarks or a set of short walls that did not block external cues. Expansion tests showed that both groups of pigeons primarily used an absolute distance strategy. However, on rotational tests, pigeons continued to search in the center of the array, suggesting that direction was learned in relation to array.     

Between ignorance and truth: Partition dependence and learning in judgment under uncertainty

In 3 studies, participants viewed sequences of multiattribute objects (e.g., colored shapes) appearing with varying frequencies and judged the likelihood of the attributes of those objects. Judged probabilities reflected a compromise between (a) the frequency with which each attribute appeared and (b) the ignorance prior probability cued by the number of distinct values that the focal attribute could take on. Thus, judged probabilities were partition dependent, varying with the number of events into which the state space was subjectively divided. This bias was diminished among participants more confident in what they learned, was strong and insensitive to level of confidence when ignorance priors were especially salient, and required ignorance priors to be salient only when probabilities were elicited (not during encoding).     

Manic thinking: independent effects of thought speed and thought content on mood

This experiment found that the speed of thought affects mood. Thought speed was manipulated via participants' paced reading of statements designed to induce either an elated or a depressed mood. Participants not only experienced more positive mood in response to elation than in response to depression statements, but also experienced an independent increase in positive mood when they had been thinking fast rather than slow--for both elation and depression statements. This effect of thought speed extended beyond mood to other experiences often associated with mania (i.e., feelings of power, feelings of creativity, a heightened sense of energy, and inflated self-esteem or grandiosity).     

Taking the task seriously: reflections on measures of color acquisition

The experiments described in the lead articles by Kowalski and Zimiles and by O'Hanlon and Roberson examine factors that lead to color term acquisition. These experiments touch on the debate regarding the relative contributions of language and concepts in word learning. In this reflection, we examine how conclusions concerning the debate depend deeply on the particular task presented to children, and we propose an alternative approach to studying color term acquisition.     

Scope of attention, control of attention, and intelligence in children and adults

Recent experimentation has shown that cognitive aptitude measures are predicted by tests of the scope of an individual's attention or capacity in simple working memory tasks and also by the ability to control attention. However, these experiments do not indicate how separate or related the scope and control of attention are. An experiment with 52 children (10 to 11 years old) and 52 college students included measures of the scope and control of attention, as well as verbal and nonverbal aptitude measures. The children showed little evidence of using sophisticated attentional control, but the scope of attention predicted intelligence in that group. In adults, both the scope and control of attention varied among individuals and accounted for considerable individual variance in intelligence. About one third that variance was shared between scope an d control, and the rest was unique to one or the other.Scope and control of attention appear to be related but distinct contributors to intelligence.     

Modeling college women's perceptions of elite leadership positions with Social Cognitive Career Theory

The utility of Social Cognitive Career Theory (SCCT; Lent, Brown, & Hackett, 1994) for predicting college women's interests and goals for positions of elite leadership was examined with 156 undergraduate women at a public university. They completed measures of elite leadership self-efficacy expectations, outcome expectations, interests, and goals. Results supported SCCT as a theoretical framework for understanding internal factors that may contribute to women's elite leadership interests and goals. Self-efficacy and outcome expectations for elite leadership positions related positively to interests and goals for such positions, and self-efficacy and outcome expectations each contributed unique variance to the prediction of elite leadership interests. Outcome expectations partially mediated the relation between elite leadership self-efficacy and interests, interests partially mediated the relation between elite leadership outcome expectations and goals, and the combination of elite leadership interests and outcome expectations completely mediated the relation between self-efficacy for elite leadership positions and elite leadership goals.     

Novel labels support 10-month-olds’ attention to novel objects

What is the source of the mutual exclusivity bias whereby infants map novel labels onto novel objects? In an intermodal preferential looking task, we found that novel labels support 10-month-olds’ attention to a novel object over a familiar object. In contrast, familiar labels and a neutral phrase gradually reduced attention to a novel object. Markman (1989, 1990) argued that infants must recall the name of a familiar object to exclude it as the referent of a novel label. We argue that 10-month-olds’ attention is guided by the novelty of objects and labels rather than knowledge of the names for familiar objects. Mutual exclusivity, as a language-specific bias, might emerge from a more general constraint on attention and learning.     

Response acquisition and fixed-ratio escalation based on interresponse times in rats

The effectiveness of a fixed‐ratio (FR) escalation procedure, developed by Pinkston and Branch (2004) and based on interresponse times (IRTs), was assessed during lever‐press acquisition. Forty‐nine experimentally naïve adult male Long Evans rats were deprived of food for 24 hr prior to an extended acquisition session. Before the start of the session, three food pellets were placed in the magazine. Otherwise, no magazine training, shaping, nor autoshaping procedure was employed. The first 20 presses each resulted in the delivery of a 45‐mg food pellet. Then, the FR increased (2, 4, 8, 11, 16, 20, 25, 30) when each IRT in the ratio was less than 2 s during three consecutive ratios. Sessions lasted 13 hr or until 500 pellets were earned. On average, rats reached a terminal ratio of 11 (mean) or 16 (median) during the first session. Seven rats reached the maximum value of FR 30 and only one rat did not acquire the response. In most rats, a break‐and‐run pattern of responding characteristic of FR schedules began to develop in this acquisition session. Subsequently, the ratio‐escalation procedure continued during daily 2‐hr sessions. In these sessions, the starting ratio requirement was set at the terminal ratio reached in the previous session. Using this procedure, over half (26) of the rats reached the FR 30 requirement by the fourth session. These data demonstrate that a ratio‐escalation procedure based on IRTs provides a time‐efficient way of establishing ratio responding.     

Observing behavior and atypically restricted stimulus control

Restricted stimulus control refers to discrimination learning with atypical limitations in the range of controlling stimuli or stimulus features. In the study reported here, 4 normally capable individuals and 10 individuals with intellectual disabilities (ID) performed two-sample delayed matching to sample. Sample-stimulus observing was recorded with an eye-tracking apparatus. High accuracy scores indicated stimulus control by both sample stimuli for the 4 nondisabled participants and 4 participants with ID, and eye tracking data showed reliable observing of all stimuli. Intermediate accuracy scores indicated restricted stimulus control for the remaining 6 participants. Their eye-tracking data showed that errors were related to failures to observe sample stimuli and relatively brief observing durations. Five of these participants were then given interventions designed to improve observing behavior. For 4 participants, the interventions resulted initially in elimination of observing failures, increased observing durations, and increased accuracy. For 2 of these participants, contingencies sufficient to maintain adequate observing were not always sufficient to maintain high accuracy; subsequent procedure modifications restored it, however. For the 5th participant, initial improvements in observing were not accompanied by improved accuracy, an apparent instance of observing without attending; accuracy improved only after an additional intervention that imposed contingencies on observing behavior. Thus, interventions that control observing behavior seem necessary but may not always be sufficient for the remediation of restricted stimulus control.