Constraining theories of embodied cognition

Influences of perceptual and motor activity on evaluation have led to theories of embodied cognition suggesting that putatively complex judgments can be carried out using only perceptual and motor representations. We present an experiment that revisited a movement-compatibility effect in which people are faster to respond to positive words by pulling a lever than by pushing a lever and are faster to respond to negative words by pushing than by pulling. We demonstrate that the compatibility effect depends on people's representation of their selves in space rather than on their physical location. These data suggest that accounting for embodied phenomena requires understanding the complex interplay between perceptual and motor representations and people's representations of their selves in space.     

On confidence intervals for within-subjects designs

Confidence intervals (CIs) for means are frequently advocated as alternatives to null hypothesis significance testing (NHST), for which a common theme in the debate is that conclusions from CIs and NHST should be mutually consistent. The authors examined a class of CIs for which the conclusions are said to be inconsistent with NHST in within-subjects designs and a class for which the conclusions are said to be consistent. The difference between them is a difference in models. In particular, the main issue is that the class for which the conclusions are said to be consistent derives from fixed-effects models with subjects fixed, not mixed models with subjects random. Offered is mixed model methodology that has been popularized in the statistical literature and statistical software procedures. Generalizations to different classes of within-subjects designs are explored, and comments on the future direction of the debate on NHST are offered.     

This construction needs learned

Four experiments are presented in which adults learned to comprehend a new syntactic construction in their native language. Experiments 1 and 2 demonstrate that adults quickly learn to comprehend the new construction and generalize it to new verbs. Experiment 3 shows that experience with the novel construction affects the processing of a construction already known to the participants and with which the novel construction is temporarily ambiguous. Experiment 4 demonstrates that the influence of a novel construction on the comprehension of familiar constructions is affected by the processing that occurred while the novel construction was learned. These results are discussed in the context of the constraint satisfaction approach to sentence processing and episodic-processing accounts of memory.     

Attentional set interacts with perceptual load in visual search

In the present study, we examined the hypothesis that perceptual load is the primary factor that determines the efficiency of attentional selection. Participants performed a visual search task under conditions of high- and low-load. In line with the perceptual load hypothesis, presenting conditions of highand low-load in separate blocks of trials resulted in processing of to-be-ignored stimuli only in the lowload condition (Experiment 1). However when high- and low-load conditions were randomly mixed in blocks of trials, the participants showed processing of to-be-ignored stimuli in both conditions, suggesting that high perceptual load is not necessarily sufficient to obtain perceptual selectivity (Experiment 2). An analysis of intertrial transition effects showed that on high-load trials, processing of to-be-ignored stimuli occurred only when the previous trial was a low-load trial. The results suggest that low perceptual load can engender broad attentional processing. On the other hand, when a high-load trial was preceded by another high-load trial, little processing of task-irrelevant stimuli was observed. The present results are discussed in terms of the interaction between expectancies and bottom-up factors in the efficiency of attentional selection.     

Human use regulatory affairs advisor (HURAA): Learning about research ethics with intelligent learning modules

The Human Use Regulatory Affairs Advisor (HURAA) is a Web-based facility that provides help and training on the ethical use of human subjects in research, based on documents and regulations in United States federal agencies. HURAA has a number of standard features of conventional Web facilities and computer-based training, such as hypertext, multimedia, help modules, glossaries, archives, links to other sites, and page-turning didactic instruction. HURAA also has these intelligent features: (1) an animated conversational agent that serves as a navigational guide for the Web facility, (2) lessons with case-based and explanation-based reasoning, (3) document retrieval through natural language queries, and (4) a context-sensitive Frequently Asked Questions segment, calledPoint & Query. This article describes the functional learning components of HURAA, specifies its computational architecture, and summarizes empirical tests of the facility on learners.     

Investigating retrospective influences on induction in rats' responding for 1% sucrose when food-pellet reinforcement is upcoming

When rats lever press for 1% sucrose reinforcement in the first half of a 50-min session, response rates are higher when food-pellet reinforcement will be available in the second half than when 1% sucrose will be available. Results of past research have suggested that, under some conditions, this induction effect is prospective in nature (i.e., controlled by the conditions of reinforcement in the present session). However, that research did not rule out the possibility that, under other conditions, retrospective factors (i.e., the conditions of reinforcement in the previous session[s]) could contribute. In the present study, rats responded in two types of session, one in which 1% sucrose reinforcement was available in both halves of the session and one in which 1% sucrose and food-pellet reinforcement were available in the first and second halves, respectively. Which type of session was in effect unsignaled and session type alternated every session (Experiment 1), every second session (Experiment 2), or after at least 20 consecutive sessions of one type (Experiment 3). Across experiments, the results indicated that it takes several sessions of one type for observable retrospective effects to occur, but those effects are short lived. These results allow the authors to identify the mechanisms that must underlie induction. The authors also discuss induction as an animal model of anticipation.     

Is induction produced by upcoming food-pellet reinforcement the outcome of an increase in overall activity or in operant responding?

Researchers have demonstrated that rats reliably increase their rates of pressing a lever for 1% liquid-sucrose reinforcement if they will soon have the opportunity to press a lever for food-pellet reinforcement. In the present experiments, the authors investigated if this increase in response rates occurred because the upcoming food pellets produced an increase in all behaviors (i.e., general arousal) or an increase in only the specific operant response (i.e., lever pressing). The results of Experiments 1 and 2 showed that the appearance of induction in rats' lever pressing for 1% sucrose reinforcement when food-pellet reinforcement was upcoming did not coincide with increases in the frequency of running in a wheel or making a nonreinforced nose-poke response. On the other hand, in Experiment 3, the authors found the appearance of induction coincided with increase nonreinforced lever presses on an adjacent lever. These results shed doubt on the idea that induction is a result of a general increase in all activity, and suggest instead that the increase in responding that occurs during induction is limited to the operant response.     

Variable solutions to the same problem: aberrant practice effects in object naming by three aphasic patients

Although deficits in confrontation naming are a common consequence of damage to the language areas of the left cerebral hemisphere, some patients with aphasia show relatively good naming ability. We measured effects of repeated practice on naming latencies for a set of pictured objects by three aphasic patients with near-normal naming ability and by neurologically intact young and older adults. While the non-injured participants showed a systematic reduction in overall mean latencies and reduced trial-to-trial latency variability, the aphasic patients did not. Examination of the latency distributions suggests that successful naming by aphasic patients may come about by different underlying operations.     

Testing the limits of cognitive plasticity in older adults: application to attentional control

Laboratory based training studies suggest that older adults can benefit from training in tasks that tap control aspects of attention. This was further explored in the present study in which older and younger adults completed an adaptive and individualized dual-task training program. The testing-the-limits approach was used [Lindenberger, U., & Baltes, P. B. (1995). Testing-the-limits and experimental simulation: Two methods to explicate the role of learning in development. Human Development, 38, 349-360.] in order to gain insight into how attentional control can be improved in older adults. Results indicated substantial improvement in overlapping task performance in both younger and older participants suggesting the availability of cognitive plasticity in both age groups. Improvement was equivalent among age groups in response speed and performance variability but larger in response accuracy for older adults. The results suggest that time-sharing skills can be substantially improved in older adults.     

Aging, memory and visual search

Potential age-related differences in the memory processes that underlie visual search are examined in the present study. Using a dynamic, gaze-contingent search paradigm developed to assess memory for previously examined distractors, older adults demonstrated no memory deficit. Surprisingly, older adults made fewer refixations compared to their younger counterparts, indicating better memory for previously inspected objects. This improved memory was not the result of a speed-accuracy trade-off or larger Inhibition-of-Return effects for older than for younger adults. Additional analyses suggested that older adults may derive their benefit from finer spatial encoding of search items. These findings suggest that some of the memory processes that support visual search are relatively age invariant.