Associative processes in repetition priming

Study-test congruence of response levels in item stimulus-response priming

We investigated stimulus-response (S-R) memory links during object priming using a binary associative size judgement paradigm. At study, participants decided which of two objects was bigger in real life and, at test, made the same or the reverse judgement. We examined the effects of response congruence on item S-R priming in the associative paradigm. In Experiment 1, a task reversal manipulation had minimal impact on RT priming when classifications were congruent for both recombined objects between study and test. Experiment 2 found that RT priming was more disrupted by classification incongruence of the selected than of the nonselected item alone, with incongruence of the nonselected object having no effect on RTs. Experiment 3, however, found that classification incongruence of both items eliminated RT priming, indicating that a significant effect of classification incongruence for the nonselected item is only evident if both items are classification-incongruent. Finally, across all experiments, we found that accuracy was more sensitive than RTs to decision/action incongruence. We interpret these findings in light of a two-stream account of S-R priming, and suggest a few extensions to account for interactions between S-R links of recombined items.

Rapid response learning of brand logo priming: Evidence that brand priming is not dominated by rapid response learning

Repetition priming increases the accuracy and speed of responses to repeatedly processed stimuli. Repetition priming can result from two complementary sources: rapid response learning and facilitation within perceptual and conceptual networks. In conceptual classification tasks, rapid response learning dominates priming of object recognition, but it does not dominate priming of person recognition. This suggests that the relative engagement of network facilitation and rapid response learning depends on the stimulus domain. Here, we addressed the importance of the stimulus domain for rapid response learning by investigating priming in another domain, brands. In three experiments, participants performed conceptual decisions for brand logos. Strong priming was present, but it was not dominated by rapid response learning. These findings add further support to the importance of the stimulus domain for the relative importance of network facilitation and rapid response learning, and they indicate that brand priming is more similar to person recognition priming than object recognition priming, perhaps because priming of both brands and persons requires individuation.

How long is long-term priming? Classification and action priming in the scale of days

Previous research has shown that stimulus–response associations comprise associations between the stimulus and the task (a classification task in particular) and the stimulus and the action performed as a response. These associations, contributing to the phenomenon of priming, affect behaviour after a delay of hundreds of trials and they are resistant against overwriting. Here, we investigate their longevity, testing their effects in short-term (seconds after priming) and long-term (24 hr and 1 week after priming) memory. Three experiments demonstrated that both stimulus–classification (S-C) and stimulus–action (S-A) associations show long-term memory effects. The results also show that retrieval of these associations can be modulated by the amount of engagement on the same task between encoding and retrieval, that is, how often participants performed this task between prime and probe sessions. Finally, results show that differences in processing time during encoding are linked to the amount of conflict caused during retrieval of S-C, but not S-A associations. These findings add new information to the existing model of priming as a memory system and pose questions about the interactions of priming and top-down control processes.

Early response activation in repetition priming: an LRP study

According to recent interpretations of repetition priming, response codes are automatically bound to a stimulus and retrieved during successive presentations of the stimulus, hence, affecting its current processing. Despite a solid corpus of behavioural evidence in line with this interpretation, electrophysiological studies have reported contrasting results regarding the nature and the timing of response code retrieval. The present experiment aims to establish at which stage of information processing decision and action codes are retrieved in repetition priming. To this end, the lateralized readiness potential (LRP) was analysed for primed faces to monitor motor cortex activity related to response preparation. Congruent and incongruent responses were obtained by having identical or reversed tasks between study and test. Primed stimuli presented LRP activations with opposite polarities for the two congruency conditions in the time-window 250-300 ms, indicating response-related motor cortex activity resulting from the retrieval of correct and incorrect decision/action codes for congruent and incongruent trials, respectively. This result indicates that decision and action codes bound to a primed stimulus are retrieved at early stages of stimulus processing and that these codes are transmitted to the motor cortex.

Defining stimulus representation in stimulus-response associations formed on the basis of task execution and verbal codes

Responding to stimuli leads to the formation of stimulus-response (S-R) associations that allow stimuli to subsequently automatically trigger associated responses. A recent study has shown that S-R associations are established not only by active task execution, but also by the simultaneous presentation of stimuli and verbal codes denoting responses in the absence of own action [Pfeuffer et al. (Journal of Experimental Psychology: Human Perception and Performance 43:328-347, 2017)]. Here, we used an item-specific priming paradigm to investigate whether the stimulus part of S-R associations formed based on task execution and verbal codes is represented in abstract or specific format by examining whether S-R associations are retrieved for perceptually different forms of the same stimulus or not. Between the prime and probe instance of a stimulus, its format switched from image to word or vice versa. We found that, irrespective of whether stimuli were primed by task execution or verbal coding, performance was impaired when S-R mappings switched rather than repeated between the prime and probe instance of a stimulus. The finding that prime S-R mappings affected probe performance even when stimulus format switched indicates that stimuli were represented in abstract form in S-R association based on both task execution and verbal coding. Furthermore, we found no performance benefits for stimuli primed and probed in the same format rather than different formats, suggesting that stimuli were not additionally represented in specific format. Overall, our findings demonstrate the adaptability of automatized behaviors and indicate that abstract stimulus representations allow S-R associations to generalize across perceptually different stimulus formats.

The impact of dose on naming accuracy with persons with aphasia

BACKGROUND

Although aphasia rehabilitation has been shown to be efficacious, many questions remain regarding how best to deliver treatment to maximize functional gains for persons with aphasia. Treatment delivery variables, such as intensity and dosage, are likely to influence both behavioral and structural changes during anomia treatment. While numerous protocols have concluded that treatment intensity positively impacts functional outcomes, few studies to date have examined the role that dose plays in patient outcomes for anomia treatment.

AIMS

This study sought to investigate how manipulating dose of repeated confrontation naming within sessions influences naming in persons with aphasia. Repeated practice of confrontation naming, without feedback, was hypothesized to improve trained but not untrained words, to be persistent after withdrawal, and to be sensitive to the number of trials (i.e., dose) within sessions.

METHODS AND PROCEDURES

A single-subject ABA design with replication across seven participants with aphasia was used to investigate the influence of repeated confrontation naming attempts on the acquisition and maintenance of trained pictures relative to untrained pictures. Training involved repeated attempts to name pictures, along with repeated exposure to pictures of objects (nouns) and their names, without feedback. The primary independent variable was within session dose; the dependent variable was naming accuracy.

OUTCOMES AND RESULTS

Naming accuracy improved for all participants for trained pictures across both acquisition and maintenance phases per visual inspection; such positive effects were not observed for untrained pictures. Effect size calculations indicate that three of seven participants demonstrated considerable change for trained items, while one of seven participants demonstrated meaningful change for untrained items. The high-dose condition elicited small effect sizes for one participant, and large effect sizes for two of seven participants, while the low-dose condition elicited small and medium effect sizes for two of seven participants.

CONCLUSIONS

Participants across a variety of aphasia severity levels responded positively to two doses of repeated confrontation naming practice, without feedback, across phases of this naming protocol. Results are in line with principles of neuroplasticity and demonstrate that repeated practice, without feedback, can produce significant and persistent changes in naming ability for some persons with aphasia.

Retrieval of bindings between task-irrelevant stimuli and responses can facilitate behaviour under conditions of high response certainty

Repetition priming can be driven by the encoding and retrieval of stimulus–response (S–R) bindings. When a previously encoded S–R binding is retrieved, and is congruent with the response currently required, it can bias response-selection processes towards selecting the retrieved response, resulting in facilitation. Previous studies have used classification tasks at retrieval. Here, two (or more) response options are competing, and it is likely that any evidence (e.g., an S–R binding) in favour of one option will be utilized to effect a decision. Thus, S–R effects are likely to be seen when using such a task. It is unclear whether such effects can be seen under conditions of higher response certainty, when participants are explicitly cued to make a response. Across two experiments, evidence for a modulating influence of S–R bindings is seen despite using a response cueing method at retrieval to minimize response uncertainty and despite stimuli being task irrelevant. Finally, the results suggest that responses within these S–R bindings are coded at the level of left versus right hand, and not a more fine-grained within-hand thumb versus index finger. The results underline the resilience of S–R effects, suggesting that they are present even under conditions where no explicit object-oriented decision is required.

Attention meets binding: only attended distractors are used for the retrieval of event files

Response-irrelevant stimuli can be encoded with, and later on retrieve, a response given to a relevant stimulus, an effect that is called distractor-response binding. In three experiments using a prime-probe design, we investigated whether the allocation of attention modulates the processes contributing to distractor-response binding. Participants identified letters via keypresses while attending to one of two sets of simultaneously presented but response-irrelevant number stimuli. In different experiments, both spatial attention and feature-based attention were allocated to the response-irrelevant stimuli. The results showed that only attended response-irrelevant stimuli elicited effects of distractor-response binding. In particular, while the encoding of response-irrelevant stimuli and responses was not particularly affected by attention during prime processing, only attended response-irrelevant stimuli in the probe retrieved previous responses. Hence, we show that attention affects action regulation due to modulating the influence of stimulus-response binding on behavior.

Dissociation of rapid response learning and facilitation in perceptual and conceptual networks of person recognition

Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition. Here, we addressed the relevance of network facilitation and rapid response learning for priming of person recognition with a view to advance general theories of priming. In four experiments, participants performed conceptual decisions like occupation or nationality judgments for famous faces. The magnitude of rapid response learning varied across experiments, and rapid response learning co-occurred and interacted with facilitation in perceptual and conceptual networks. These findings indicate that rapid response learning and facilitation in perceptual and conceptual networks are complementary rather than competing theories of priming. Thus, future memory theories need to incorporate both rapid response learning and network facilitation as individual facets of priming.

Incongruent abstract stimulus-response bindings result in response interference: FMRI and EEG evidence from visual object classification priming

Stimulus repetition often leads to facilitated processing, resulting in neural decreases (repetition suppression) and faster RTs (repetition priming). Such repetition-related effects have been attributed to the facilitation of repeated cognitive processes and/or the retrieval of previously encoded stimulus-response (S-R) bindings. Although previous research has dissociated these two forms of learning, their interaction in the brain is not fully understood. Utilizing the spatial and temporal resolutions of fMRI and EEG, respectively, we examined a long-lag classification priming paradigm that required response repetitions or reversals at multiple levels of response representation. We found a repetition effect in occipital/temporal cortex (fMRI) that was time-locked to stimulus onset (EEG) and robust to switches in response, together with a repetition effect in inferior pFC (fMRI) that was time-locked to response onset (EEG) and sensitive to switches in response. The response-sensitive effect occurred even when changing from object names (words) to object pictures between repetitions, suggesting that S-R bindings can code abstract representations of stimuli. Most importantly, we found evidence for interference effects when incongruent S-R bindings were retrieved, with increased neural activity in inferior pFC, demonstrating that retrieval of S-R bindings can result in facilitation or interference, depending on the congruency of response between repetitions.

The status of rapid response learning in aging

Strong evidence exists for an age-related impairment in associative processing under intentional encoding and retrieval conditions, but the status of incidental associative processing has been less clear. In 2 experiments, we examined the effects of age on rapid response learning-the incidentally learned stimulus-response association that results in a reduction in priming when a learned response becomes inappropriate for a new task. Specifically, we tested whether priming was equivalently sensitive in both age groups to reversal of the task-specific decision cue. Experiment 1 showed that cue inversion reduced priming in both age groups with a speeded inside/outside classification task, and in Experiment 2, cue inversion eliminated priming on an associative version of this task. Thus, the ability to encode an association between a stimulus and its initial task-specific response appears to be preserved in aging. These findings provide an important example of a form of associative processing that is unimpaired in older adults.

The effect of feedback schedule manipulation on speech priming patterns and reaction time

Speech priming tasks are frequently used to delineate stages in the speech process such as lexical retrieval and motor programming. These tasks, often measured in reaction time (RT), require fast and accurate responses, reflecting maximized participant performance, to result in robust priming effects. Encouraging speed and accuracy in responding can take many forms, including verbal instructions and feedback, and often involves visually displayed RT feedback. However, it is uncertain how manipulation of the schedule of this RT feedback influences speech RT speed and, ultimately, the priming effect. This experiment examined the effect of visually presented RT feedback schedules on priming patterns in 20 older healthy adults. Results suggested that feedback schedule manipulation had a differential effect on reaction time, depending on the interstimulus interval between the prime and the target, but no effect on response priming patterns.

Sizing up the associative account of repetition priming

Three studies which test an associative account of repetition priming in a size comparison task are reported. Congruence of decision between priming and test affected performance when the priming task and test tasks were the same but not when they differed. This congruence effect was unaffected by the proportion of trials with congruent responses. Same-task priming exceeded cross-task priming even when both tasks required the same aspect of semantic knowledge. The results indicate that a component of priming is due to associations which are formed during priming and automatically activated when stimuli are repeated at test. Stimuli do not become associated with motor responses but are associated with the results of processing at a number of other levels.

Does the presence of priming hinder subsequent recognition or recall performance?

Declarative and non-declarative memories are thought be supported by two distinct memory systems that are often posited not to interact. However, Wagner, Maril, and Schacter (2000a) reported that at the time priming was assessed, greater behavioural and neural priming was associated with lower levels of subsequent recognition memory, demonstrating an interaction between declarative and non-declarative memory. We examined this finding using a similar paradigm, in which participants made the same or different semantic word judgements following a short or long lag and subsequent memory test. We found a similar overall pattern of results, with greater behavioural priming associated with a decrease in recognition and recall performance. However, neither various within-participant nor various between-participant analyses revealed significant correlations between priming and subsequent memory performance. These data suggest that both lag and task have effects on priming and declarative memory performance, but that they are largely independent and occur in parallel.

Item to decision mapping in rapid response learning

Repeated classification of a visually presented stimulus rapidly leads to a form of response learning that bypasses the original evaluation in favor of a more efficient response mechanism. In two experiments, we examined the level of input and output representations that make up this form of learning. In Experiment 1, alterations in the finger mapping of the output response had no effect on the expression of response learning, demonstrating that a classification decision, not motor output, is associated with repeated items. In Experiments 2A and 2B, we tested whether response learning would transfer across different visual exemplars of a studied item. There was no evidence of transfer to different visual exemplars, even when these exemplars were judged to be highly visually similar. Taken together, these results indicate that response learning consists of the formation of an association between a specific visual representation and a classification decision.

Retrieval of incidental stimulus-response associations as a source of negative priming

Priming effects of ignored distractor words were investigated in a task-switching situation that allowed an orthogonal variation of priming and response compatibility between prime and probe. Across 3 experiments, the authors obtained a disordinal interaction of priming and response relation. Responding was delayed in the ignored repetition condition if different responses were required for identical stimuli in the prime and probe (negative priming). Repeating the prime distractor in the probe facilitated responding if the same response was required in the prime and in the probe (positive priming). The same pattern of results was replicated in a letter-matching task without task switching (Experiment 4). Findings lend support to a new model that explains negative priming in terms of an automatic retrieval of incidental stimulus-response associations.

Specificity of priming: a cognitive neuroscience perspective

Priming is a nonconscious form of memory that involves a change in a person's ability to identify, produce or classify an item as a result of a previous encounter with that item or a related item. One important question relates to the specificity of priming - the extent to which priming reflects the influence of abstract representations or the retention of specific features of a previous episode. Cognitive neuroscience analyses provide evidence for three types of specificity: stimulus, associative and response. We consider empirical, methodological and conceptual issues that relate to each type of specificity, and suggest a theoretical perspective to help in guiding future research.