Semantic priming of person recognition: Categorial priming may be a weaker form of the associative priming effect

An interactive activation and competition account (Burton, Bruce, & Johnston, 1990) of the semantic priming effect in person recognition studies relies on the fact that primes and targets (people) have semantic information in common. However, recent investigations into the type of relationship needed to mediate the semantic priming effect have suggested that the prime and target must be close associates (e.g., Barry, Johnston, & Scanlan, 1998; Young, Flude, Hellawell, & Ellis, 1994). A review of these and similar papers suggests the possibility of a small but non-reliable effect based purely on categorial relationships. Experiment 1 provided evidence that when participants were asked to make a name familiarity decision it was possible to boost this small categorial effect when multiple (four) primes were presented prior to the target name. Results from Experiment 2 indicated that the categorial effect was not due to the particular presentation times of the primes. This boosted categorial effect was shown to cross domains (names to faces) in Experiment 3 and persist in Experiment 4 when the task involved naming the target face. The similarity of the pattern of results produced by the associative priming effect and this boosted categorial effect suggests that the two may be due to the same underlying mechanism in semantic memory.     

Event-related potentials and recognition memory

According to dual-process models, recognition memory is supported by distinct retrieval processes known as familiarity and recollection. Important evidence supporting the dual-process framework has come from studies using event-related brain potentials (ERPs). These studies have identified two topographically distinct ERP correlates of recognition memory--the "parietal" and "mid-frontal" old/new effects--that are dissociated by variables that selectively modulate recollection and familiarity, respectively. We evaluate the extent to which ERP data support dual-process models in light of the proposal that recollection is a continuous rather than a discrete memory process. We also examine the claim that the putative ERP index of familiarity is a reflection of implicit rather than explicit memory. We conclude that ERP findings continue to offer strong support for the dual-process perspective.     

Event-related potentials, semantic processes, and expectancy factors in word recognition

Electrophysiological activity was recorded at 16 scalp locations during a word recognition task in order to investigate the effect of expectancy factors on ERPs. In each of 160 trials two stimuli (S1 and S2) were presented with a stimulus onset asynchrony (SOA) of 1500 msec. There were four experimental conditions. In the word-antonym (W-A) and the word-nonantonym (W-NA) conditions, both S1 and S2 were words. The subjects' task was to think of the antonym to S1 and respond as fast as possible after the presentation of S2 by pressing a "YES" button if S2 was an antonym to S1 (in the W-A trials), or a "NO" button if S2 was not an antonym to S1 (in the W-NA trials). In the nonword-word (NW-W) and nonword-nonword (NW-NW) conditions S1 was a nonword, while S2 was either a word (in NW-W trials) or a nonword (in NW-NW trials). If S1 was not a word, the subjects were instructed to wait for S2, and respond as fast as possible by pressing the "YES" button if it was a word an the "NO" button if it was not a word. EEG was sampled during a time epoch that started 100 msec before the onset of S1 and continued for another 2560 msec. The ERPs were analyzed separately for each experimental condition and for time epochs related to S1, to S2, and to the SOA. Expected antonyms were recognized significantly faster than any other words or nonwords. The RTs to words in the W-NA and NW-W condition, and to nonwords in the NW-NW condition did not differ significantly from each other. The ERP difference between the four conditions following S2 was interpreted in terms of a negative-going potential which appeared prior to the P300, during a time period which started 200 msec and ended 550 msec from stimulus onset. The negativity related to nonwords was significantly larger than the negativity related to words. The negativity related to the expected antonym was almost nonexistent. It is speculated that this negativity has the same origin as N400, and that it might be related to the process of lexical access.     

Event-related potentials indicate context effect in reading ambiguous words

The aim of the study was a comparison of lexical and contextual factors in understanding ambiguous words in German. First, a sample of native speakers selected 56 words having maximally strong differences between a dominant and a subordinate meaning. After this, another sample from the same population was visually presented with sentences that activated dominant or subordinate meanings of the words and were accompanied by probes associated with dominant or subordinate meanings. This resulted in a crossed design with two factors: sentence dominant vs. sentence subordinate and probe dominant vs. probe subordinate. An analysis of event-related brain potentials revealed a large, long-lasting and highly-significant N400 wave whenever the meaning of the probe was incongruent with the meaning of the sentence and the lack of this wave whenever the two meanings were congruent. In the typical N400 space and time, the effect was independent of whether the lexical word meaning was dominant or subordinate. At other sites and times, however (e.g., at lateral frontal electrodes F7/F8, and after 700 ms), the congruence effect was significant after dominant sentences only. The data indicate that lexical factors have a rather limited influence on the activation of a particular meaning of ambiguous words. A strong context can virtually override even a very strong difference in the preference for different meanings.     

The locus of semantic priming effects in person recognition

Semantic priming in person recognition has been studied extensively. In a typical experiment, participants are asked to make a familiarity decision to target items that have been immediately preceded by related or unrelated primes. Facilitation is usually observed from related primes, and this priming is equivalent across stimulus domains (i.e., faces and names prime one another equally). Structural models of face recognition (e.g., IAC: Burton, Bruce, & Johnston, 1990) accommodate these effects by proposing a level of person identity nodes (PINs) at which recognition routes converge, and which allow access to a common pool of semantics. We present three experiments that examine semantic priming for different decisions. Priming for a semantic decision (e.g., British/American?) shows exactly the same pattern that is normally observed for a familiarity decision. The pattern is equivalent for name and face recognition. However, no semantic priming is observed when participants are asked to make a sex decision. These results constrain future models of face processing and are discussed with reference to current theories of semantic priming.     

The structure of semantic person memory: evidence from semantic priming in person recognition

This paper reviews research on the structure of semantic person memory as examined with semantic priming. In this experimental paradigm, a familiarity decision on a target face or written name is usually faster when it is preceded by a related as compared to an unrelated prime. This effect has been shown to be relatively short lived and susceptible to interfering items. Moreover, semantic priming can cross stimulus domains, such that a written name can prime a target face and vice versa. However, it remains controversial whether representations of people are stored in associative networks based on co-occurrence, or in more abstract semantic categories. In line with prominent cognitive models of face recognition, which explain semantic priming by shared semantic information between prime and target, recent research demonstrated that priming could be obtained from purely categorically related, non-associated prime/target pairs. Although strategic processes, such as expectancy and retrospective matching likely contribute, there is also evidence for a non-strategic contribution to priming, presumably related to spreading activation. Finally, a semantic priming effect has been demonstrated in the N400 event-related potential (ERP) component, which may reflect facilitated access to semantic information. It is concluded that categorical relatedness is one organizing principle of semantic person memory.     

Indirect object recognition: evidence for associative processes in recognition memory

Rats' exploration of stimulus P (e.g., a domestic object) is reduced following either its direct exposure or its indirect exposure and is taken to indicate recognition memory. Procedures for demonstrating indirect object recognition involve an initial presentation of object P with stimulus X (and of an object Q with stimulus Y). On test, stimulus X is presented with objects P and Q and rats' exploration of Q exceeds their exploration of P. One interpretation here is that the presentation of stimulus X on test associatively activates the memory of object P, which diminishes exploration of P relative to Q. It is possible, instead, that performance is simply the result of a novel pattern of stimulation generated by the unfamiliar combination of X and Q. The authors modified this procedure to reduce the likelihood of such a process. Their procedure involved first the presentation of PX and QY before the presentation of stimulus X alone. During the test that followed, objects P and Q were presented but stimulus X was removed. The authors found that exploration of Q remained greater than that of P despite these modifications and discuss some theoretical implications of indirect, associative processes in recognition memory.     

Modulations of sensory-evoked brain potentials indicate changes in perceptual processing during visual-spatial priming.

Reaction time (RT) differences to visual stimuli as a function of expectancy have been attributed to changes in perceptual processing or entirely to shifts in decision and response criteria. To help distinguish between these competing interpretations, event-related brain potentials (ERPs) were recorded to lateralized flashes delivered to visual field locations precued by a central arrow (valid stimuli) or not precued (invalid stimuli). Validly cued stimuli in both simple and choice RT tasks elicited consistent amplitude enhancements of the early, sensory-evoked PI component of the ERP recorded at scalp sites overlying lateral prestriate visual cortex (90-130 ms poststimulus). In contrast, the subsequent N1 component (150-200 ms) was enhanced by validly cued stimuli in the choice RT task condition only. These electrophysiological findings support models proposing that the behavioral effects of precuing expected target locations are due, at least in part, to changes in sensory-perceptual processing. Furthermore, these data provide specific information regarding the neural mechanisms underlying such effects.     

Event-related potentials to schematic faces in social phobia

Social phobia has been associated with an attentional bias for angry faces. This study aimed at further characterising this attentional bias by investigating reaction times, heart rates, and ERPs while social phobics, spider phobics, and controls identified either the colour or the emotional quality of angry, happy, or neutral schematic faces. The emotional expression of angry faces did not interfere with the processing of their colour in social phobics, and heart rate, N170 amplitude and parietal late positive potentials (LPPs) of these subjects were also no different from those of non-phobic subjects. However, social phobics showed generally larger P1 amplitudes than non-phobic controls with spider phobic subjects in between. No general threat advantage for angry faces was found. All groups identified neutral schematic faces faster and showed larger late positive amplitudes to neutral than to emotional faces. Furthermore, in all groups the N170 was modulated by the emotional quality of faces. This effect was most pronounced in the emotion identification task.     

Independence of data-driven and conceptually driven priming: the case of person recognition

A central tenet of current memory theories is the independence of data-driven and conceptually driven priming. Although these types of repetition priming have different functional properties, it has remained unclear whether they are independent and additive or interact with each other. Therefore, we orthogonally combined these priming types in two experiments requiring occupation judgments for celebrities, represented by their faces or names. In both experiments, the sum of the effects of separate data-driven priming and conceptually driven priming equaled the effect of the combination of these priming types. These findings demonstrate for the first time the independence of data-driven and conceptually driven priming and so confirm a central tenet of current memory theories. This independence may thus be an important element for the development of future overarching memory theories.     

Semantic and associative priming in picture naming

We report four picture-naming experiments in which the pictures were preceded by visually presented word primes. The primes could either be semantically related to the picture (e.g., "boat" - TRAIN: co-ordinate pairs) or associatively related (e.g., "nest" - BIRD: associated pairs). Performance under these conditions was always compared to performance under unrelated conditions (e.g., "flower" - CAT). In order to distinguish clearly the first two kinds of prime, we chose our materials so that (a) the words in the co-ordinate pairs were not verbally associated, and (b) the associate pairs were not co-ordinates. Results show that the two related conditions behaved in different ways depending on the stimulus-onset asynchrony (SOA) separating word and picture appearance, but not on how long the primes were presented. When presented with a brief SOA (114 ms, Experiment 1), the co-ordinate primes produced an interference effect, but the associated primes did not differ significantly from the unrelated primes. Conversely , with a longer SOA (234 ms, Experiment 2) the co-ordinate primes produced no effect, whereas a significant facilitation effect was observed for associated primes, independent of the duration of presentation of the primes. This difference is interpreted in the context of current models of speech production as an argument for the existence, at an automatic processing level, of two distinguishable kinds of meaning relatedness.     

Associative and categorical relations in the associative memory illusion

What kinds of associations underlie the associative memory illusion? In Experiment 1, lists composed of horizontal, or coordinate, free associates elicited false recognition of critical lures much more often than did lists composed of vertical, or subordinate, category instances. Experiment 2 replicated this result, and showed that the difference between free associates and category instances was not an artifact of differential levels of forward or backward associative strength. Associative structure plays an important role in the associative memory illusion: The illusion is strongest when the critical lure lies at the same level of categorization as the studied items.     

Event-related brain potentials elicited during word recognition by adult good and poor phonological decoders

Cognitive processing of lexical and sub-lexical stimuli was compared for good and poor adult phonological decoders. Sixteen good decoders and 16 poor decoders, average age 19 years, silently read 150 randomly computer presented sentences ending in incongruous regular, irregular, or nonwords and 100 congruent filler sentences. Electro-encephalographic recordings were made from the final word of each incongruous sentence. Although no significant group differences were found, good decoders showed specialised hemispheric word recognition processing at P200 and P300. Nonwords elicited greater N200 and P300 amplitudes for both good and poor decoders. Larger amplitude P200s were elicited by poor decoders when processing nonwords. These findings provide evidence for separable lexical and sub-lexical procedures and support a psychophysiological basis for a core phonological deficit in poor phonological decoders.     

Event-related potentials related to normal and morphed emotional faces

S. Bentin and L. Y. Deouell (2000) have suggested that face recognition is achieved through a special-purpose neural mechanism, and its existence can be identified by a specific event-related potential (ERP) correlate, the N170 effect. In the present study, the authors explored the structural significance of N170 by comparing normal vs. morphed stimuli. They used a morphing procedure that allows a fine modification of some perceptual details (first-order relations). The authors also aimed to verify the independence of face identification from other cognitive mechanisms, such as comprehension of emotional facial expressions, by applying an emotion-by-emotion analysis to examine the emotional effect on N170 ERP variation. They analyzed the peak amplitude and latency variables in the temporal window of 120-180 ms. The ERP correlate showed a classic N170 ERP effect, more negative and more posteriorly distributed for morphed faces compared with normal faces. In addition, they found a lateralization effect, with a greater right-side distribution of the N170, but not directly correlated to the morphed or normal conditions. Two cognitive codes, structural and expression, are discussed, and the results are compared with the multilevel model proposed by V. Bruce and A. W. Young (1986, 1998).     

Event-related brain potentials to grammatical errors and semantic anomalies

Event-related brain potentials (ERPs) were recorded while subjects silently read several prose passages, presented one word at a time. Semantic anomalies and various grammatical errors had been inserted unpredictably at different serial positions within some of the sentences. The semantically inappropriate words elicited a large N400 component in the ERP, whereas the grammatical errors were associated with smaller and less consistent components that had scalp distributions different from that of the N400. This result adds to the evidence that the N400 wave is more closely related to semantic than to grammatical processing. Additional analyses revealed that different ERP configurations were elicited by open-class (“content”) and closed-class (“function”) words in these prose passages.     

Disproportionate deficit in associative recognition relative to item recognition in global amnesia

In two experiments, we tested the hypothesis that medial temporal lobe (MTL) amnesic patients and, likewise, diencephalic (DNC) amnesic patients evidence a disproportionate deficit in memory for associations in comparison with memory for single items. In Experiment 1, we equated item recognition in amnesic and control participants and found that, under these conditions, associative recognition remained impaired both for MTL patients and for DNC patients. To rule out an alternative interpretation of the results of Experiment 1, in Experiment 2 we compared the performance of amnesic and control participants on a one-item recognition task and a two-item recognition task that required no memory for the association between members of word pairs. In the MTL group, when single-item recognition was equated to that of the controls, two-item nonassociative pair memory was equivalent as well. In the DNC group, nonassociative pair memory was impaired, but this impairment did not fully account for the impairment in associative memory. These findings indicate that memory for novel associations between items is disproportionately impaired in comparison with memory for single items in amnesia.     

Unconscious priming by color and form: different processes and levels

Using a metacontrast masking paradigm, prior studies have shown (a) that a target's color information and form information, can be processed without awareness and (b) that unconscious color processing occurs at early, wavelength-dependent levels in the cortical information processing hierarchy. Here we used a combination of paracontrast and metacontrast masking techniques to explore unconscious color and form priming effects produced by blue, green, and neutral stimuli. We found that color priming in normal observers is significantly reduced when an additional paracontrast mask precedes the target at optimal masking SOAs. However, no reduction of form-priming effects was obtained at similar optimal paracontrast SOAs. We conclude that unconscious color priming depends on an early, wavelength- or stimulus-dependent response of color neurons located at early cortical levels whereas unconscious form priming occurs at later levels.     

The time course of semantic and associative priming effects is different in an attentional blink task

When two targets are presented using rapid serial visual presentation (RSVP) and the interval between the targets is 200–500 ms, report of the second target is impaired, a phenomena known as the attentional blink (AB). This study examined the time course of semantic-only and associate–semantic priming effects during an AB task. Three RSVP experiments were conducted using targets that shared either a semantic-only or an associative–semantic relationship. The results of the three experiments demonstrated semantic-only priming effects at the shortest stimulus onset asynchronies (SOAs). Associative–semantic priming was evident at shorter and longer SOAs. This suggests that priming in an AB task is driven by conceptual overlap facilitating lexical access at short SOAs and with longer SOAs lexical access benefits from word associations links between targets.