Abstract stimuli associated with threat through conditioning cannot be detected preattentively

Studies of anxiety suggest that threat stimuli can be identified preattentively, but this conclusion is questionable because of possible low-level perceptual confounds. Two experiments used visual search tasks in which abstract shapes were conditioned to carry neutral or negative valence. Experiment 1 found generally faster responses to threat-associated abstract stimuli but no evidence that they were detected preattentively, irrespective of trait anxiety level. A similar pattern was found in Experiment 2, in which individuals high in snake or spider fear showed no evidence of preattentive detection of abstract stimuli associated with their feared object. In contrast, implicit behavioral measures showed significant effects of conditioning, demonstrating that targets associated with threat were negatively evaluated in these experiments.     

Integration of cardiac responses to serial stimuli after Pavlovian conditioning in rats

The expression of cardiac responses to sequences of two sounds was studied in restrained rats following discriminative trace or delay conditioning. Stimuli paired with a tail shock 10 sec later (CS1) elicited conditioned bradycardia. Unpaired or neutral stimuli (CS0) elicited mostly tachycardia. Rats did not learn to suppress responding to nonreinforced sequences with an interval of 6 sec between sounds. Responses to the second stimulus were significantly augmented following a CS1 stimulus, but not following a CS0 stimulus. Real-time summation of simple responses provided a more complete and quantitative prediction of dual responses than did resetting or facilitation. These results extend the time range over which summation may be observed from less than 2 sec to at least 16 sec. They appear to be inconsistent with models involving competition between unitary representations of stimuli in short-term memory and suggest the existence of multiple stimulus traces with independent time courses.     

Emergent conditional discrimination in children: Matching to compound stimuli

This study reports two experiments that first taught preschool children identity-matching to compound sample and compound comparison stimuli. A compound stimulus consisted of a colour and a form superimposed on one another. Test sessions assessed whether children related the form and colour elements of a particular compound stimulus. The test for this was matching to sample in which an arbitrary conditional discrimination was required. A majority of the children selected the correct colour comparison in the presence of each form sample. The children also showed the reverse sample-comparison relations: they matched form comparisons to the corresponding colour samples, respectively. In the context of these arbitrary relations, new colours were paired with the form elements of the samples (Experiment 1), and new form elements were paired with the colour elements of the comparisons (Experiment 2). Subsequent tests assessed whether the new stimulus elements had control over responding when presented as single samples or comparisons. Test results showed that most subjects were able to relate the new stimulus elements to the corresponding colour and form elements, respectively. The study demonstrated that matching to compound stimuli in training and testing conditionsMaygenerate conditional relations between the individual stimulus elements.     

Adventitious control by the location of comparison stimuli in conditional discriminations.

In a conditional discrimination procedure, samples appeared in a center key, and comparisons appeared in two of four outer keys. The location of comparison keys varied from trial to trial. Separate learning curves for each of the six possible pairs of comparison keys were plotted in a signal-detection space, revealing different patterns of progress on each pair. Also, when learned conditional discriminations were disrupted, pairs of keys differed in their patterns of disruption. Varying the location of comparison stimuli among six different pairs of keys had not eliminated key position as a controlling aspect of the stimuli. The variations simply increased the number of stimulus compounds--key position and experimental stimuli--that the subject learned. Plotting conditional-discrimination learning curves in a signal-detection space reveals relations among hits, false alarms, accuracy, and comparison preference that help to define a subject's progress.     

Short-term memory for "surprising" versus "expected" unconditioned stimuli in Pavlovian conditioning.

Rabbits were trained via a Pavlovian eyelid-conditioning regime to respond differentially to a conditioned stimulus (CSR) depending on whether or not that stimulus was preceded several seconds earlier by a preparatory stimulus consisting of an electric shock otherwise employed as an unconditioned stimulus (UCS). Following training, differential responding to CSR varied systematically with the interval between the preparatory stimulus and CSR, consistent with assumptions concerning decay of information in short-term memory. The major finding, however, involved the test effects of announcing the preparatory stimulus by either a conditioned stimulus with which it had otherwise been paired (CS+) or a conditioned stimulus with which it had otherwise been systematically unpaired (CS-). The greater differential responding to the following CSR in the latter case is taken to support the notion that a "surprising" UCS is more likely to be retained (rehearsed) in short-term memory than is an "expected" UCS.     

Conjoint control of performance in conditional discriminations by successive and simultaneous stimuli.

In a conditional discrimination, reinforcement of pigeons' responses to pairs of simultaneously presented wavelength stimuli depended on the orientation of white lines superimposed on the wavelengths. Over different conditions in Experiment 1, three wavelength differences were combined with two differences between successively presented line orientations. Measures of stimulus discriminability increased with increases in the difference between both orientation and wavelength stimuli. Conditional-discrimination performance was thus conjointly determined by stimulus disparity in the successive and simultaneous discriminations. In Experiment 2, ratios of rates of reinforcement contingent upon the two categories of correct responses were varied over several conditions for difficult and easy discriminations. Ratios of responses to wavelength pairs were sensitive to variations in the reinforcement ratio to a greater extent for the more difficult orientation discrimination than for the easier orientation discrimination. Performance in the conditional discrimination was therefore determined by the interacting effects of stimulus disparity and the relative rates of reinforcement contingent upon the two correct choices. It was concluded that the effect of temporally distant reinforcement on behavior in a prevailing schedule component is attenuated to an extent that depends on similarity of stimuli that delineate the successive components.     

Differences in the effect of Pavlovian contingencies upon behavioral momentum using auditory versus visual stimuli.

We examined the role of Pavlovian and operant relations in behavioral momentum by arranging response-contingent alternative reinforcement in one component of a three-component multiple concurrent schedule with rats. This permitted the simultaneous arranging of different response-reinforcer (operant) and stimulus-reinforcer (Pavlovian) contingencies during three baseline conditions. Auditory or visual stimuli were used as discriminative stimuli within the multiple concurrent schedules. Resistance to change of a target response was assessed during a single session of extinction following each baseline condition. The rate of the target response during baseline varied inversely with the rate of response-contingent reinforcement derived from a concurrent source, regardless of whether the discriminative stimuli were auditory or visual. Resistance to change of the target response, however, did depend on the discriminative-stimulus modality. Resistance to change in the presence of visual stimuli was a positive function of the Pavlovian contingencies, whereas resistance to change was unrelated to either the operant or Pavlovian contingencies when the discriminative stimuli were auditory. Stimulus salience may be a factor in determining the differences in resistance to change across sensory modalities.     

Leonardo's constraint: two opaque objects cannot be seen in the same direction

Given Leonardo's constraint that 2 opaque objects cannot be seen in the same direction, how are the regions of objects occluded to 1 eye included in perception? To answer this question, the authors presented 3-dimensional stimuli, similar to the ones that concerned Leonardo, and measured the visual directions of their monocular and binocular regions. When the distance between near and far objects was large, the nonfixated object was seen as double and blurry. Leonardo's constraint was met by seeing the near object as double and transparent or the distant object as double and superimposed. When the distance between near and far objects was small, the constraint was met by a perceptual displacement and compression of parts of the nonfixated object.     

Sensory and conceptual representations in memory: Motor images that cannot be imaged

Summary The paper argues for a distinction between sensory-and conceptual-information storage in the human information-processing system. Conceptual information is characterized as meaningful and symbolic, while sensory information may exist in modality-bound form. Furthermore, it is assumed that sensory information does not contribute to conscious remembering and can be used only in data-driven process reptitions, which can be accompanied by a kind of vague or intuitive feeling. Accordingly, pure top-down and willingly controlled processing, such as free recall, should not have any access to sensory data. Empirical results from different research areas and from two experiments conducted by the authors are presented in this article to support these theoretical distinctions. The experiments were designed to separate a sensory-motor and a conceptual component in memory for two-digit numbers and two-letter items, when parts of the numbers or items were imaged or drawn on a tablet. The results of free recall and recognition are discussed in a theoretical framework which distinguishes sensory and conceptual information in memory.     

Reinforcement and the organization of behavior in golden hamsters: Pavlovian conditioning with food and shock unconditioned stimuli

The effects of Pavlovian conditioned stimuli (CSs) for food or shock on a variety of behaviors of golden hamsters were observed in three experiments. The aim was to see whether previously reported differences among the behaviors produced by food reinforcement and punishment procedures could be accounted for by differential effects of Pavlovian conditioning on the behaviors. There was some correspondence between the behaviors observed to the CSs and the previously reported effects of instrumental training. However, the Pavlovian conditioned responses (CRs) alone would not have predicted the effects of instrumental training. Moreover, CRs depended to some extent on the context in which training and testing occurred. These findings, together with others in the literature, suggest that the results of Pavlovian conditioning procedures may not unambiguously predict what system of behaviors will be most readily modified by instrumental training with a given reinforcer.     

"Good and bad, I defined these terms, quite clear no doubt somehow": Neuroimaging and competency to be executed after Panetti

There has been little consideration, in either the caselaw or the scholarly literature, of the potential impact of neuroimaging on cases assessing whether a seriously mentally disabled death row defendant is competent to be executed. The Supreme Court's 2007 decision in Panetti v. Quarterman significantly expanded its jurisprudence by ruling that such a defendant had a constitutional right to make a showing that his mental illness "obstruct[ed] a rational understanding of the State's reason for his execution." This article considers the impact of neuroimaging testimony on post-Panetti competency determination hearings, and looks at multiple questions of admissibility of evidence, adequacy of counsel, availability of expert assistance, juror attitudes, trial tactics, and application of the Daubert doctrine, and also considers the implications of the lesser-known Panetti holding (that enhances the role of expert witnesses in all competency-to-be-executed inquiries). It warns that the power of the testimony in question has the capacity to inappropriately affect fact-finders in ways that may lead "to outcomes that are both factually and legally inaccurate and constitutionally flawed."     

To be is not always to be The hypothesis of cognitive universality in the light of studies on elliptic language behaviour

Abstract.— This paper introduces evidence as to whether the cognitive base of natural languages is universal or not. When a speaker or writer has too little time or space to use complete, grammatically well-formed sentences, he will first leave out the parts of speech which are least essential for the decoding process of the receiver. If, in two different languages, different parts are left out, the cognitive base of the languages cannot be the same. It was predicted that native Finnish-speaking subjects will be more prone to leave out the verb from newspapers headings and from reports of sporting events, than will native Swedish-speaking subjects. In addition, it was expected that Finnish subjects will rate sentences lacking verbs as more, and sentences lacking nouns, as less "language correct" than will Swedish subjects. It was also predicted that in perception of a sporting event, Finnish reporters will focus on topological, and Swedish, on vectorial, information. The predictions were borne out exactly by the findings, which thus are strongly negative to the universality hypothesis.     

Inhibitory tagging in visual search can be found if search stimuli remain visible

Klein (1988) reported that inhibitory tagging (i.e., inhibition of return in visual search) made reaction times for the detection of small probes increase at locations where there had previously been rejected items in serial visual search. It is reasonable that the attended and rejected locations are inhibited. However, subsequent studies did not support Klein's idea. In these studies, inhibitory tagging was tested after removing the items from the search tasks. The paradigms in these studies were not appropriate for testing an object-based inhibitory effect because the objects (i.e., items) were removed from the display. In the present study, we found that evidence of inhibitory tagging could be observed only when the items of the search tasks were maintained until the responses for the small probes were made. This appeared to be an object-based effect.     

Hypothetical high-level cognitive functions cannot be localized in the brain: another argument for a revitalized behaviorism

A key epistemological difference between behaviorism and cognitivism concerns their respective attitudes toward the analysis of so-called cognitive processes into functional modules. Behaviorists generally say it is not possible. Cognitivists argue that this is an achievable goal. The question has been concretized by recent developments in brain imaging technology. A consideration of the matter suggests that technical and conceptual difficulties abound in the effort to localize "high-level cognitive functions" in narrowly circumscribed regions of the brain. Some of the most serious involve the ambiguous definition of the putative mental components that are to be localized and the generally unacknowledged nonlinear complexity of both psychological processes and the brain. In addition, the imaging techniques themselves are replete with technical difficulties that raise additional questions about this particular application, even though these wonderful machines can make extraordinary contributions to our knowledge of brain anatomy and physiology. The cumulative implication of these difficulties is that the cognitive approach to the study of scientific psychology has once again set out on a search for a chimera. New approaches to behaviorism may be required to set psychology back on the correct track.