Knowledge that Transforms

When people are presented with backward-masked images of fear-relevant stimuli and only some of these images are paired consistently with electric shocks, they can predict the occurrence of shocks even though they do not consciously know which images they have seen. We postulated that they may use the perception of visceral cues from the conditional fear response to facilitate the prediction of shocks. In this study, ability to detect heartbeats was used to index sensitivity to visceral cues. The results showed that subjects who could detect their heartbeats performed better than chance in predicting whether or not they would receive a shock during the conditioning task. The findings support the notion that hunches, or "gut feelings," are based in part on the perception of visceral cues.

Several models of person perception predict that expectancy violations have both affective and cognitive consequences for the perceiver. Although extant evidence generally supports these claims, the temporal resolution of traditional self-report measures has limited researchers' ability to convincingly link underlying physiological processes with observed outcomes. In this study, we examined these issues by measuring brain (event-related brain potentials) and peripheral (facial electromyogram) electrophysiological activity while participants read positive and negative expectancy-consistent, expectancy-violating, expectancy-irrelevant, and semantically incongruent behavioral sentences about fictitious characters. The electromyogram results indicated that negative (but not positive) expectancy-violating behaviors elicited enhanced negative affect as early as 100 to 300 ms poststimulus. The event-related potentials showed enhanced positivities with latency exceeding 300 ms in response to expectancy violations and negative behaviors. Semantically incongruent sentence endings influenced a separate negative component (N400), suggesting fundamental differences between semantic- and behavior-consistency processing. This difference also was evident in participants' recall. Implications for theoretical models of expectancy violation are discussed.

Affine geometry is a generalization of Euclidean geometry in which distance can be scaled along parallel directions, though relative distances in different directions may be incommensurable. This article presents a new procedure for testing the intrinsic affine structure of a psychological space by having subjects perform bisection judgments over multiple directions. If those judgments are internally consistent with one another, they must satisfy a theorem first proved by Pierre Varignon around 300 years ago. In the experiment reported here, this procedure was employed to measure the perceived structure of a visual ground surface. The results revealed that observers' judgments were systematically distorted relative to the physical environment, but that the judged bisections in different directions had an internally consistent affine structure. Implications of these findings for other possible response tasks are considered.

Most events are processed by a number of neural pathways. These pathways often differ considerably in processing speed. Thus, coherent perception requires some form of synchronization mechanism. Moreover, this mechanism must be flexible, because neural processing speed changes over the life of an organism. Here we provide behavioral evidence that humans can adapt to a new intersensory temporal relationship (which was artificially produced by delaying visual feedback). The conflict between these results and previous work that failed to find such improvements can be explained by considering the present results as a form of sensorimotor adaptation.

In three studies, we explored how the ending of a life influences the perceived desirability of that life. We consistently observed that participants neglected duration in judging the global quality of life. Across all the studies, the end of life was weighted heavily, producing ratings that contradict a simple hedonic calculus in which years of pleasure and pain are summed. Respondents rated a wonderful life that ended abruptly as better than one with additional mildly pleasant years (the "James Dean Effect"). Similarly, a terrible life with additional moderately bad years was rated as more desirable than one ending abruptly without those unpleasant years (the "Alexander Solzhenitsyn Effect"). Finally, embedding moderately intense years in the middle of life did not produce effects as strong as adding those years to the end of life, suggesting that a life's ending is weighted especially heavily in judging quality of life.

Previous work has shown that newborn infants categorically discriminate the fundamental syntactic category distinction between lexical and grammatical words. In this article, we show that by the age of 6 months, infants prefer to listen to lexical over grammatical words. In Experiment 1, infants were habituated to a list of either lexical or grammatical words, and then tested on new lists of words from the same and the contrasting categories. The infants showed recovery to lexical words after habituation to grammatical words but not vice versa. This asymmetry indicates a possible preference for lexical words. In Experiments 2 and 3, preference was assessed directly by presenting infants with alternating trials of lexical and grammatical words, in the central-fixation preference procedure. The infants looked significantly longer during lexical-word than grammatical-word trials. These results show that by 6 months, infants attend preferentially to lexical words. The implications of this emerging attentional preference for subsequent language acquisition are discussed.

Determining how, cognition and emotion interact is pivotal to an understanding of human behavior and its disorders. Available data suggest that changes in emotional reactivity and behavior associated with drinking are intertwined with alcohol's effects on cognitive processing. In the study reported here, we demonstrated that alcohol dampens anticipatory fear and response inhibition in human participants not by directly suppressing subcortical emotion centers, as posited by traditional tension-reduction theories, but instead by impairing cognitive-processing capacity. During intoxication, reductions in fear response (assessed via startle potentiation) occurred only under dual-stimulus conditions, and coincided with reduced attentional processing of threat cues as evidenced by brain response (assessed via P3 event-related potentials). The results are consistent with higher cortical mediation of alcohol 's effects on fear, and illustrate more broadly how disruption of a cognitive process can lead to alterations in emotional reactivity and adaptive behavior.

Understanding spoken language is an exceptional computational achievement of the human cognitive apparatus. Theories of how humans recognize spoken words fall into two categories: Some theories assume a fully bottom-up flow of information, in which successively more abstract representations are computed. Other theories, in contrast, assert that activation of a more abstract representation (e.g., a word) can affect the activation of smaller units (e.g., phonemes or syllables). The two experimental conditions reported here demonstrate the top-down influence of word representations on the activation of smaller perceptual units. The results show that perceptual processes are not strictly bottom-up: Computations at logically lower levels of processing are affected by computations at logically more abstract levels. These results constrain and inform theories of the architecture of human perceptual processing of speech.

Two identical visual targets moving across each other can be perceived either to bounce off or to stream through each other. A brief sound at the moment the targets coincide biases perception toward bouncing. We found that this bounce-inducing effect was attenuated when other identical sounds (auditory flankers) were presented 300 ms before and after the simultaneous sound. The attenuation occurred only when the simultaneous sound and auditory flankers had similar acoustic characteristics and the simultaneous sound was not salient. These results suggest that there is an aspect of auditory-grouping (saliency-assigning) processes that is context-sensitive and can be utilized by the visual system for solving ambiguity. Furthermore, control experiments revealed that such auditory context did not affect the perceptual qualities of the simultaneous sound. Because the attenuation effect is not manifest in the perception of acoustic characteristics of individual sound elements, we conclude that it is a genuine cross-modal effect.

Recent research has demonstrated that the act of remembering can prompt temporary forgetting or, more specifically, the inhibition of particular items in memory. Extending work of this kind, the present research investigated some possible boundary conditions of retrieval-induced forgetting. As expected, a critical determinant of temporary forgetting was the interval between guided retrieval practice and a final recall test. When these two phases were separated by 24 hr, retrieval-induced forgetting failed to emerge. When they occurred in the same testing session, however, retrieval practice prompted the inhibition of related items in memory (i.e., Experiment 1). A delay of 24 hr between the encoding of material and guided retrieval practice reduced but did not eliminate retrieval-induced forgetting (i.e., Experiment 2). These findings are considered in the wider context of adaptive forgetting.