A parallel distributed processing model of visual word recognition and pronunciation is described. The model consists of sets of orthographic and phonologlc ~ units and an interlevel of hidden units. Weights on connections between units were modified during a training phase using the back-propa-gation learning algorithm. The model simulates many aspects of human performance, including (a) differences bet~n~.'n words in terms of processing difficulty, (b) pronunciation of novel items, (c) differences between readers in terms of word recognition skill, (d) transitions from beginning to skilled reading, and (e) differences in performance on lexieal decision and naming tasks. The model's behavior early in the learning phase corresponds to that of children acquiring word recognition skills. Training with a smaller number of hidden units produces output characteristic of many dys-lexic readers. Naming is simulated without pronunciation rules, and lexical decisions are simulated without accessing word-level representations. The performance of the model is largely determined by three factors: the nature of the input, a significant fragment of written English; the learning rule, which encodes the implicit structure of the orthography in the weights on connections; and the architecture of the system, which influences the scope of what can be learned. The recognition and pronunciation of words is one of the cen-

This article presents a theory in which automatization is construed as the acquisition of a domain-specific knowledge base, formed of separate representations, instances, of each exposure to the task. Processing is considered automatic if it relies on retrieval of stored instances, which will occur only after practice in a consistent environment. Practice is important because it increases the amount retrieved and the speed of retrieval; consistency is important because it ensures that the retrieved instances will be useful. The theory accounts quantitatively for the power-function speed-up and predicts a power-function reduction in the standard deviation that is constrained to have the same exponent as the power function for the speed-up. The theory accounts for qualitative properties as well, explaining how some may disappear and others appear with practice. More generally, it provides an alternative to the modal view of automaticity, arguing that novice performance is limited by a lack of knowledge rather than a scarcity of resources. The focus on learning avoids many problems with the modal view that stem from its focus on resource limitations. Automaticity is an important phenomenon in everyday men-tal life. Most of us recognize that we perform routine activities quickly and effortlessly, with little thought and conscious aware-ness--in short, automatically (James, 1890). As a result, we of-ten perform those activities on "automatic pilot " and turn our minds to other things. For example, we can drive to dinner while conversing in depth with a visiting scholar, or we can make coffee while planning dessert. However, these benefits may be offset by costs. The automatic pilot can lead us astray, caus-ing errors and sometimes catastrophes (Reason & Myceilska, 1982). If the conversation is deep enough, we may find ourselves and the scholar arriving at the office rather than the restaurant, or we may discover that we aren't sure whether we put two or three scoops of coffee into the pot. Automaticity is also an important phenomenon in skill acqui-sition (e.g., Bryan & Harter, 1899). Skills are thought to consist largely of collections of automatic processes and procedures

What was noted by E. J. hanger (1978) remains true today: that much of contemporary psychological research is based on the assumption that people are consciously and systematically processing incoming information in order to construe and interpret their world and to plan and engage in courses of action. As did E. J. hanger, the authors question this assumption. First, they review evidence that the ability to exercise such conscious, intentional control is actually quite limited, so that most of moment-to-moment psychological life must occur through nonconscious means if it is to occur at all. The authors then describe the different possible mechanisms that produce automatic, environmental control over these various phenomena and review evidence establishing both the existence of these mechanisms as well as their consequences for judgments, emotions, and

The effects of prior semantic context upon lexical access during sentence comprehension were examined in two experiments. In both studies, subjects comprehended auditorily presented sentences containing lexical ambiguities and simultaneously performed a lexical decision task upon visually presented letter strings. Lexical decisions for visual words related to each of the meanings of the ambiguity were facilitated when these words were presented simultaneous with the end of the ambiguity (Experiment 1). This effect held even when a strong biasing context was present ` When presented four syllables following the ambiguity, only lexical decisions for visual words related to the contextually appropriate meaning of the ambiguity were facilitated (Experiment 2). Arguments are made for autonomy of the lexical access process of a model of semantic context effects is offered. Sentence comprehension requires the integration of information derived from a number of ongoing cognitive processes. It is clear, for example, that semantic and syntactic contexts interact with moment-to-moment comprehension processes to affect our interpretation of individual words and sentences; observations that contexts act to determine sentential interpretations abound in the literature. However, while this effect is well documented, the process by which it occurs is not. Until the manner in which contexts exert their effects (i.e., the nature of information interaction) can be detailed, claims relying on the concept of "contextual determination" are empty and merely beg the question.

People often have trouble performing 2 relatively simple tasks concurrently. The causes of this interference and its implications for the nature of attentional limitations have been controversial for 40 years, but recent experimental findings are beginning to provide some answers. Studies of the psychological refractory period effect indicate a stubborn bottleneck encompassing the process of choosing actions and probably memory retrieval generally, together with certain other cognitive operations. Other limitations associated with task preparation, sensory-perceptual processes, and timing can generate additional and distinct forms of interference. These conclusions challenge widely accepted ideas about attentional resources and probe reaction time methodologies. They also suggest new ways of thinking about continuous dual-task performance, effects of extraneous stimulation (e.g.. stop signals), and automaticity. Implications for higher mental processes are discussed. For more than 100 years, psychologists have been interested in people's ability (or inability) to perform two or more activities concurrently. One reason these limitations provoke curiosity is simply that people wonder what is humanly possible. This question has obvious significance for practical problems such

We present a theory of priming that is designed to account for phenomena usually attributed to the action of a spreading activation process. The theory assumes that a prime and target are combined at retrieval into a compound cue that is used to access memory. If the representations of the prime and target are associated in memory, the match is greater than if they are not associated, and this greater match facilitates the response to the target. The compound cue mechanism can be implemented within the framework of several memory models; descriptions of these implementations are presented. We summarize empirical results that have been taken as evidence for a spreading activation process and show that the retrieval theory can also account for these phenomena and that, in some cases, the retrieval theory provides predictions that are more constrained than those provided by spreading activation theories. Also, two experiments are reported that address predictions about the range of priming (in terms of number of connected concepts) and the decay rate of priming (in terms of intervening items). In both eases, the retrieval theory provides a better account of the data than spreading activation. Finally, contrasts between the compound cue theory and long-term priming phenomena are presented. Because the amount of information stored in human memory

Neuroimaging and neuropsychological studies have implicated left inferior prefrontal cortex (LIPC) in both semantic and phonological processing. In this study, functional magnetic resonance imaging was used to examine whether separate LIPC regions participate in each of these types of processing. Performance of a semantic decision task resulted in extensive LIPC activation compared to a perceptual control task. Phonological processing of words and pseudowords in a syllable-counting task resulted in activation of the dorsal aspect of the left inferior frontal gyrus near the inferior frontal sulcus (BA44/45) compared to a perceptual control task, with greater activation for nonwords compared to words. In a direct comparison of semantic and phonological tasks, semantic processing preferentially

Accounts of language processing have suggested that it requires retrieving concepts from memory in response to an ongoing stream of information. This can be facilitated by inferring the gist of a sentence, conversation, or document, and using that computational problem underlying the extraction and use of gist, formulating this problem as a rational statistical inference. This leads us to a novel approach to semantic representation in which word meanings are represented in terms of a set of probabilistic topics. The topic model performs well in predicting word association and the effects of semantic association and ambiguity on a variety of language processing and memory tasks. It also provides a foundation for developing more richly structured statistical models of language, as the generative process assumed in the topic model can easily be extended to incorporate other kinds of semantic and syntactic structure. Many aspects of perception and cognition can be understood by considering the computational problem that is addressed by a particular human capacity (Andersion, 1990; Marr, 1982). Perceptual capacities such as identifying shape from shading (Freeman, 1994), motion perception

Results of 3 studies support the notion that anchoring is a special case of semantic priming; specifi-cally, information that is activated to solve a comparative anchoring task will subsequently be more accessible when participants make absolute judgments. By using the logic of priming research, in Study 1 the authors showed that the strength of the anchor effect depends on the applicability of activated information. Study 2 revealed a contrast effect when the activated information was not representative for the absolute judgment and the targets of the 2 judgment tasks were sufficiently different. Study 3 demonstrated that generating absolute judgments requires more time when compara-tive judgments include an implausible anchor and can therefore be made without relevant target information that would otherwise be accessible. In current psychological research, 'few phenomena are easier to demonstrate and harder to explain than the so-called anchor-ing effect, a biased estimate toward an arbitrary value considered by judges before making a numerical estimate (Jacowitz & Kahneman, 1995). In one of the best known and most typical anchoring studies I (Tversky & Kahneman, 1974), research par-

Topics come and go in social psychology, and this is one that is coming. This is the first Handbook of Social Psychology with a chapter devoted to the role of control and automaticity in social life. Handbooks have varied somewhat over the years in how they subdivide the field, acting as barometers to measure the relative importance of topics over time-so we are happy to note that this time around control and automaticity have surfaced as key concepts in the way social psychology is being understood. These are not. however, flash-in-the-pan ideas. The distinction between automaticity and control of behavior has been with us at least since David Hartley remarked in Observations on Man (1749) that "The Motions of the body are of two kinds, automatic and voluntary. " Notions of control and automaticity have far earlier pedigrees than this. however. in the philosophical study of free will and detemtinism, and have resurfaced in psychology as fundamental themes in the debates earlier in this century between the cognitivists and behaviorists. Perhaps as a reflection of these foundations. and also for contemporary reasons we examine in this chapter, it now turns out that control and automaticity have developed into mature and important organizing ideas for the understanding of social behavior. The tricky questions of when and how people Work on this chapter was supponed in pan by the National Institute of