工作记忆和长时记忆共享信息表征的ERP证据

工作记忆和长时记忆共享记忆系统的信息表征网络, 关系密切。实验采用事件相关电位技术记录长时记忆信息对工作记忆的长时语义启动和工作记忆对相关长时记忆信息的长时语义启动。结果显示：与新项目相比, 学习项(即长时记忆信息)对工作记忆的目标信息产生了明显的行为启动效应, N2潜伏期、波幅和P3潜伏期也表现出明显的神经启动效应, 即, 学习项比新项目的反应时更短、N2和P3的潜伏期更短、N2更正, 但学习对非记忆项的影响不大; 工作记忆对相关的长时记忆信息也产生了神经启动, 表现在类别比较任务中记忆类信息比其他信息(即, 与工作记忆任务中的信息无关的内容)的N400更正。而且, 这种神经启动也会因刺激重复次数的增多而降低：与新项目相比, 学习项会使与之语义类似信息的N400更负。上述两种长时语义启动的存在及其ERPs的神经启动均为长时记忆和工作记忆使用共同信息表征的观点提供了证据支持。证据还表明, 在工作记忆和长时记忆的相互作用中注意是关键的调节因素。     

How to switch on and switch off semantic priming effects for natural and artifactual categories: activation processes in category memory depend on focusing specific feature dimensions

"Semantic priming" refers to the phenomenon that people react faster to target words preceded by semantically related rather than semantically unrelated words. We wondered whether momentary mind sets modulate semantic priming for natural versus artifactual categories. We interspersed a category priming task with a second task that required participants to react to either the perceptual or action features of simple geometric shapes. Focusing on perceptual features enhanced semantic priming effects for natural categories, whereas focusing on action features enhanced semantic priming effects for artifactual categories. In fact, significant priming effects emerged only for those categories thought to rely on the features activated by the second task. This result suggests that (a) priming effects depend on momentary mind set and (b) features can be weighted flexibly in concept representations; it is also further evidence for sensory-functional accounts of concept and category representation.     

Electrophysiological evidence for size invariance in masked picture repetition priming

This experiment examined invariance in object representations through measuring event-related potentials (ERPs) to pictures in a masked repetition priming paradigm. Pairs of pictures were presented where the prime was either the same size or half the size of the target object and the target was either presented in a normal orientation or was a normal sized mirror reflection of the prime object. Previous masked repetition priming studies have found a cascade of priming effect sensitive to perceptual (N190/P190) and semantic (N400) properties of the stimulus. This experiment found that both early (N190/P190 effects) and later effects (N400) were invariant to size, whereas only the N190/P190 effect was invariant to mirror reflection. The combination of a small prime and a mirror reflected target led to no significant priming effects. Taken together, the results of this set of experiments suggests that object recognition, more specifically, activating an object representation, occurs in a hierarchical fashion where overlapping perceptual information between the prime and target is necessary, although not always sufficient, to activate a higher level semantic representation.     

The time course of object encoding

Four experiments examined the effects of encoding time on object identification priming and recognition memory. After viewing objects in a priming phase, participants identified objects in a rapid stream of non-object distracters; display times were gradually increased until the objects could be identified (Experiments 1-3). Participants also made old/new recognition judgments about previously viewed objects (Experiment 4). Reliable priming for object identification occurred with 150 ms of encoding and reached a maximum after about 300 ms of encoding time. In contrast, reliable recognition judgments occurred with 75 ms of encoding and continued to improve for encoding times of up to 1200 ms. These results suggest that recognition memory may be based on multiple levels of object representation, from rapidly activated representations of low-level features to semantic knowledge associated with the object. In contrast, priming in this object identification task may be tied specifically to the activation of representations of object shape.     

Semantic activation in action planning

Four experiments investigated activation of semantic information in action preparation. Participants either prepared to grasp and use an object (e.g., to drink from a cup) or to lift a finger in association with the object's position following a go/no-go lexical-decision task. Word stimuli were consistent to the action goals of the object use (Experiment 1) or to the finger lifting (Experiment 2). Movement onset times yielded a double dissociation of consistency effects between action preparation and word processing. This effect was also present for semantic categorizations (Experiment 3), but disappeared when introducing a letter identification task (Experiment 4). In sum, our findings indicate that action semantics are activated selectively in accordance with the specific action intention of an actor.     

Color perception involves color representations firstly at a semantic level and then at a lexical level

Studies and models have suggested that color perception first involves access to semantic representations of color. This result leads to two questions: (1) is knowledge able to influence the perception of color when associated with a color? and (2) can the perception of color really involve only semantic representations? We developed an experiment where participants have to discriminate the color of a patch (yellow vs. green). The target patch is preceded either by a black-and-white line drawing or by a word representing a natural object associated with the same or a different color (banana vs. frog). We expected a priming effect for pictures because, with a 350-ms SOA, they only involve access to semantic representations of color, whereas words seem only elicit an access to lexical representations. As expected, we found a priming effect for pictures, but also for words. Moreover, we found a general slowdown of response times in the word-prime-condition suggesting the need of an additional processing step to produce priming. In a second experiment, we manipulated the SOA in order to preclude a semantic access in the word-prime-condition that could explain the additional step of processing. We also found a priming effect, suggesting that interaction with perception occurs at a lexical level and the additional step occurs at a color perception level. In the discussion, we develop a new model of color perception assuming that color perception involves access to semantic representations and then access to lexical representations.     

Limitations of semantic priming procedures for automatic goal activation

According to the auto-motive model, behavioral goals can be automatically activated by situational cues and may subsequently guide behavior without individual awarness. Semantic priming has become a popular paradigm for investigating effects of automatic goal activation. Nevertheless, a critical assumption of the model, i.e., that goals can be activated by semantic primes related to situational features associated with the goal, is often assumed rather than tested in experiments using semantic priming procedures. Results of four studies testing the potential of such a prime for goal activation by assessing emotional responses, subjective goal importance, behavioral intentions, and enhanced perception of goal-related stimuli do not support this assumption. The implications of these findings and a critical evaluation of results of other studies are discussed in terms of possible limitations of semantic priming procedures for testing hypotheses derived from the auto-motive model.     

Intuition in the context of object perception: intuitive gestalt judgments rest on the unconscious activation of semantic representations

Intuition denotes the ability to judge stimulus properties on the basis of information that is activated in memory, but not consciously retrieved. In three experiments we show that participants discriminated better than chance fragmented line drawings depicting meaningful objects (coherent fragments) from fragments consisting of randomly displaced line segments (incoherent fragments) or from fragments which were rotated by 180 degrees (inverted fragments), even if participants did not consciously recognize the objects. Unrecognized coherent, but not incoherent or inverted fragments produced reliable priming of correct object names in a lexical decision task, indicating that coherent fragments activated an unconscious semantic object representation. Priming effects were larger for coherent fragments judged as coherent compared to coherent fragments judged as incoherent. We conclude that intuitive gestalt judgments for coherent fragments rested on the activation of semantic object representations, which biased participants' intuitive impression of "gestalt-ness" even when the underlying object representations remained unconscious.     

What’s in an object file? Evidence from priming studies

Six experiments were conducted to investigate the nature of the contents of object files, temporary representations that store information about objects. Experiment 1 used a lexical priming paradigm with a lexical decision task, in which the prime and target could appear in either the same or different locations. The results indicated a greater priming effect when the prime and target appeared in the same location than when they appeared in different locations (object- or location-specific priming). Experiment 2 replicated these findings for objects that changed position during the display. Experiment 3 demonstrated that these findings reflected the inclusion of abstract identity information, rather than physical form, in object files. Three additional experiments tested for the presence of three types of semantic information (related concepts, semantic features, and category membership) in object files. No object-specific priming effects were found. Taken together, these experiments suggest that an object file includes identity information, but not semantic information. Implications of the results for object file theory are discussed.     

Dissociative effects of viewpoint and semantic priming on action and semantic decisions: evidence for dual routes to action from vision

This article reports evidence that two variables—object viewpoint and semantic priming—differentially affect action and semantic decisions to objects. Changing the viewing angle of an object, so that its graspable parts are oriented away from observers, disrupted action decisions but had little effect on semantic categorization. In contrast, semantic priming influenced semantic categorization and object naming, but not action decisions. Action priming, however, did not affect performance. These selective effects are consistent with the existence of separate semantic and direct (nonsemantic) routes to action from vision.     

Seven principles of goal activation: a systematic approach to distinguishing goal priming from priming of non-goal constructs.

Countless studies have recently purported to demonstrate effects of goal priming; however, it is difficult to muster unambiguous support for the claims of these studies because of the lack of clear criteria for determining whether goals, as opposed to alternative varieties of mental representations, have indeed been activated. Therefore, the authors offer theoretical guidelines that may help distinguish between semantic, procedural, and goal priming. Seven principles that are hallmarks of self-regulatory processes are proposed: Goal-priming effects (a) involve value, (b) involve postattainment decrements in motivation, (c) involve gradients as a function of distance to the goal, (d) are proportional to the product of expectancy and value, (e) involve inhibition of conflicting goals, (f) involve self-control, and (g) are moderated by equifinality and multifinality. How these principles might help distinguish between automatic activation of goals and priming effects that do not involve goals is discussed.     

Transfer between vision and haptics: Memory for 2-D patterns and 3-D objects

Explicit memory tests such as recognition typically access semantic, modality-independent representations, while perceptual implicit memory tests typically access presemantic, modality-specific representations. By demonstrating comparable cross- and within-modal priming using vision and haptics with verbal materials (Easton, Srinivas, & Greene, 1997), we recently questioned whether the representations underlying perceptual implicit tests were modality specific. Unlike vision and audition, with vision and haptics verbal information can be presented in geometric terms to both modalities. The present experiments extend this line of research by assessing implicit and explicit memory within and between vision and haptics in the nonverbal domain, using both 2-D patterns and 3-D objects. Implicit test results revealed robust cross-modal priming for both 2-D patterns and 3-D objects, indicating that vision and haptics shared abstract representations of object shape and structure. Explicit test results for 3-D objects revealed modality specificity, indicating that the recognition system keeps track of the modality through which an object is experienced.     

On the dynamics of action representations evoked by names of manipulable objects

Two classes of hand action representations are shown to be activated by listening to the name of a manipulable object (e.g., cellphone). The functional action associated with the proper use of an object is evoked soon after the onset of its name, as indicated by primed execution of that action. Priming is sustained throughout the duration of the word's enunciation. Volumetric actions (those used to simply lift an object) show a negative priming effect at the onset of a word, followed by a short-lived positive priming effect. This time-course pattern is explained by a dual-process mechanism involving frontal and parietal lobes for resolving conflict between candidate motor responses. Both types of action representations are proposed to be part of the conceptual knowledge recruited when the name of a manipulable object is encountered, although functional actions play a more central role in the representation of lexical concepts.     

Automatic Semantic Priming: The Contribution of Lexical- and Semantic-level Processes

It has recently been argued that the facilitation between associated primetarget pairs observed in automatic semantic priming tasks is due to lowlevel lexical effects. Any ''pure'' semantic priming is thought to be the result of strategic effects and does not therefore reflect automatic access to lexical semantic representations (e.g. Shelton & Martin, 1992). Not only are such claims based on a narrow definition of semantic relatedness as category comembership, but it is argued that the methodology employed by Shelton and Martin and other advocates of the intra-lexical priming hypothesis, who have attempted to dissociate semantic and associative effects by devising non-associated semantic prime-target pairs, is fundamentally flawed. Instead, an experiment is reported in which purely lexical-level primes are compared directly with semantic-level primes for the same target items in a sequential lexical decision task. Both types of prime produce facilitation, but only that from the semantic-level primes is significant. It is argued that, contrary to the intra-lexical priming hypothesis, semantic information is required for automatic semantic priming. If it were not, the lexical-level priming in this experiment would have been greater than the semantic-level priming. As it is, the reverse pattern is reported, providing support for the notion of a semantic contribution to the facilitation observed between associated prime-target pairs.     

Reflecting on the action or its outcome: Behavior representation level modulates high level outcome priming effects on self-agency experiences

Recent research suggests that one can have the feeling of being the cause of an action’s outcome, even in the absence of a prior intention to act. That is, experienced self-agency over behavior increases when outcome representations are primed outside of awareness, prior to executing the action and observing the resulting outcome. Based on the notion that behavior can be represented at different levels, we propose that priming outcome representations is more likely to augment self-agency experiences when the primed representation corresponds with a person’s behavior representation level. Three experiments, using different priming and self-agency tasks, both measuring and manipulating the level of behavior representation, confirmed this idea. Priming high level outcome representations enhanced experienced self-agency over behavior more strongly when behavior was represented at a higher level, rather than a lower level. Thus, priming effects on self-agency experiences critically depend on behavior representation level.     

Dissociative effects of viewpoint and semantic priming on action and semantic decisions: Evidence for dual routes to action from vision

This article reports evidence that two variables—object viewpoint and semantic priming—differentially affect action and semantic decisions to objects. Changing the viewing angle of an object, so that its graspable parts are oriented away from observers, disrupted action decisions but had little effect on semantic categorization. In contrast, semantic priming influenced semantic categorization and object naming, but not action decisions. Action priming, however, did not affect performance. These selective effects are consistent with the existence of separate semantic and direct (nonsemantic) routes to action from vision.     

Semantic negative priming in picture categorization and naming

Ignoring a particular stimulus can hamper subsequent attended processing of the same stimulus, a phenomenon known as 'negative priming'. Previous research has yielded partial support for the claim that the effect results from the attentional inhibition of central representations, as suggested by the fact that it appears to extend to semantic associates of ignored stimuli. In the current experiment, participants categorized or named pictorial stimuli with superimposed distractor pictures; the effect of unrelated, identical, or categorically related previously ignored pictures was investigated. Furthermore, visual similarity between categorically related picture pairs was manipulated in the naming task. The results indicated negative priming from identical ignored pictures irrespective of task. However, semantic negative priming was observed in the categorization task only. In the naming task, even visual overlap between categorically related picture pairs failed to induce negative priming. These findings argue against a central locus of the negative priming effect.     

Activation and integration of motor components in a short-term priming paradigm

The aim of the present research was to study the processes involved in knowledge emergence. In a short-term priming paradigm, participants had to categorize pictures of objects as either "kitchen objects" or "do-it-yourself tools". The primes and targets represented objects belonging to either the same semantic category or different categories (object category similarity), and their use involved gestures that were either similar or very different (gesture similarity). The condition with a SOA of 100ms revealed additive effects of motor similarity and object category similarity, whereas another condition with a SOA of 300ms showed an interaction between motor and category similarity. These results were interpreted in terms of the activation and integration processes involved in the emergence of mental representations.     

Representing the meanings of object and action words: the featural and unitary semantic space hypothesis

This paper presents the Featural and Unitary Semantic Space (FUSS) hypothesis of the meanings of object and action words. The hypothesis, implemented in a statistical model, is based on the following assumptions: First, it is assumed that the meanings of words are grounded in conceptual featural representations, some of which are organized according to modality. Second, it is assumed that conceptual featural representations are bound into lexico-semantic representations that provide an interface between conceptual knowledge and other linguistic information (syntax and phonology). Finally, the FUSS model employs the same principles and tools for objects and actions, modeling both domains in a single semantic space. We assess the plausibility of the model by showing that it can capture generalizations presented in the literature, in particular those related to category-related deficits, and show that it can predict semantic effects in behavioral experiments for object and action words better than other models such as Latent Semantic Analysis (Landauer & Dumais, 1997) and similarity metrics derived from Wordnet (Miller & Fellbaum, 1991).     

Representation and competition in the perception of spoken words

We present data from four experiments using cross-modal priming to examine the effects of competitor environment on lexical activation during the time course of the perception of a spoken word. The research is conducted from the perspective of a distributed model of speech perception and lexical representation, which focuses on activation at the level of lexical content. In this model, the strength of competition between simultaneously active lexical items depends on the degree of coherence between their distributed semantic and phonological representations. Consistent with this model, interference effects are more complete when the purely semantic aspects of these coactive representations are probed (using semantic priming) than when phonological aspects are probed as well (using repetition priming).