Evidence of vocal and manual event files in auditory negative priming

Target enhancement but not distractor suppression in auditory neural tracking during continuous speech

Selective attention modulates the neural tracking of speech in auditory cortical regions. It is unclear whether this attentional modulation is dominated by enhanced target tracking, or suppression of distraction. To settle this long-standing debate, we employed an augmented electroencephalography (EEG) speech-tracking paradigm with target, distractor, and neutral streams. Concurrent target speech and distractor (i.e., sometimes relevant) speech were juxtaposed with a third, never task-relevant speech stream serving as neutral baseline. Listeners had to detect short target repeats and committed more false alarms originating from the distractor than from the neutral stream. Speech tracking revealed target enhancement but no distractor suppression below the neutral baseline. Speech tracking of the target (not distractor or neutral speech) explained single-trial accuracy in repeat detection. In sum, the enhanced neural representation of target speech is specific to processes of attentional gain for behaviorally relevant target speech rather than neural suppression of distraction.

The Control of Event-File Management

According to the Theory of Event Coding, both perceived and self-produced events are coded by binding codes of the features of these events into event files. Here I argue that distinguishing between the actual binding process and the retrieval of event files is empirically difficult but theoretically important. As a first step towards disentangling these processes, I provide a brief overview of what the available evidence tells us with respect to the control of the binding process and the control of the retrieval process. I argue that there is not much evidence for selectivity of the binding process: Various kinds of stimuli and actions seem to be spontaneously integrated under various conditions, and there is increasing evidence that emotions, task instructions, and task context are coded into event files as well. On the other hand, there is increasing evidence for a high degree of selectivity of the retrieval process, suggesting that most if not all observations of effective impact on event files reflect an impact on retrieval, but not binding proper. I conclude by pointing out open questions and issues.

The persisting influence of unattended auditory information: Negative priming in intentional auditory attention switching

We studied negative priming (NP) in auditory attention switching. In a cued variant of dichotic listening, two spoken number words were presented, one to each ear, one spoken by a female, and one spoken by a male voice. A visual cue indicated whether the male or female voice was the target. A numerical magnitude judgement of the target number was required. The selection criterion could either switch or repeat across trials, so there were attention switch and repetition trials. Two experiments examined NP (distractor becomes target) and also included a "competitor priming" (CP) condition (target becomes distractor), relative to a "no priming" condition (target and distractor not related to previous trial). In Experiment 1, we investigated the basic priming effects. In Experiment 2, we additionally varied the response-cue interval (RCI; 100 ms vs. 1,900 ms) to examine time-related changes in priming. We found longer response times (RT) for switch trials compared with repetition trials (attention switch costs)-that is, when the internal processing context changed. In addition, we found longer RT for NP trials as well as reduced switch costs in long RCI, suggesting that previously relevant attentional settings dissipate over longer time. However, NP was not influenced by attention switches, and it was also not affected by RCI. Hence, NP in auditory attention switching does not seem strongly context or time sensitive.

Response-retrieval in identity negative priming is modulated by temporal discriminability

Reaction times to previously ignored information are often delayed, a phenomenon referred to as negative priming (NP). Rothermund et al. (2005) proposed that NP is caused by the retrieval of incidental stimulus-response associations when consecutive displays share visual features but require different responses. In two experiments we examined whether the features (color, shape) that reappear in consecutive displays, or their level of processing (early-perceptual, late-semantic) moderate the likelihood that stimulus-response associations are retrieved. Using a perceptual matching task (Experiment 1), NP occurred independently of whether responses were repeated or switched. Only when implementing a semantic-matching task (Experiment 2), negative priming was determined by response-repetition as predicted by response-retrieval theory. The results can be explained in terms of a task-dependent temporal discrimination process (Milliken et al., 1998): Response-relevant features are encoded more strongly and/or are more likely to be retrieved than irrelevant features.

Stimulus-response bindings in priming

People can rapidly form arbitrary associations between stimuli and the responses they make in the presence of those stimuli. Such stimulus-response (S-R) bindings, when retrieved, affect the way that people respond to the same, or related, stimuli. Only recently, however, has the flexibility and ubiquity of these S-R bindings been appreciated, particularly in the context of priming paradigms. This is important for the many cognitive theories that appeal to evidence from priming. It is also important for the control of action generally. An S-R binding is more than a gradually learned association between a specific stimulus and a specific response; instead, it captures the full, context-dependent behavioral potential of a stimulus.

Intact episodic retrieval in older adults: evidence from an auditory negative priming task

BACKGROUND/STUDY CONTEXT: The negative priming effect has been traditionally interpreted as the inhibitory aftereffect of distractor processing. According to inhibitory deficit theory, older adults should be more impaired by auditory distractors. Recent studies have shown that episodic retrieval processes are involved in the effect. However, so far there is no direct evidence that this is true for older adults.

METHODS

In an auditory four-alternative identification task, young adults (18-30 years), younger seniors (60-67 years), and older seniors (68-78 years) identified target sounds while ignoring distractor sounds. In ignored repetition trials, the prime distractor was repeated as the probe target, whereas there was no stimulus repetition in control trials. Reaction times and errors were analyzed.

RESULTS

Negative priming was present in all age groups. Senior groups showed increased negative priming in reaction times. All age groups revealed a comparable increase of probe errors with the former prime response in ignored repetition compared with control trials. There was no age difference in the frequency of responding with the former prime response in control trials.

CONCLUSION

An increase in prime response errors in ignored repetition trials is consistent with the involvement of episodic retrieval processes in negative priming in younger and older adults. Inconsistent with both an inhibitory account of negative priming and the inhibitory deficit theory of cognitive aging, older adults neither showed evidence of reduced negative priming nor of impaired restraint control.

Auditory spatial negative priming: what is remembered of irrelevant sounds and their locations?

The categorization and identification of previously ignored visual or auditory stimuli is typically slowed down--a phenomenon that has been called the negative priming effect and can be explained by the episodic retrieval of response-inadequate prime information and/or an inhibitory model. A similar after-effect has been found in visuospatial tasks: participants are slowed down in localizing a visual stimulus that appears at a previously ignored location. In the auditory modality, however, such an after-effect of ignoring a sound at a specific location has never been reported. Instead, participants are impaired in their localization performance when the sound at the previously ignored location changes identity, a finding which is compatible with the so-called feature-mismatch hypothesis. Here, we describe the properties of auditory spatial in contrast to visuospatial negative priming and report two experiments that specify the nature of this auditory after-effect. Experiment 1 shows that the detection of identity-location mismatches is a genuinely auditory phenomenon that can be replicated even when the sound sources are invisible. Experiment 2 reveals that the detection of sound-identity mismatches in the probe depends on the processing demands in the prime. This finding implies that the localization of irrelevant sound sources is not the inevitable consequence of processing the auditory prime scenario but depends on the difficulty of the target search process among distractor sounds.

On the robustness of prime response retrieval processes: evidence from auditory negative priming without probe interference

Visual negative priming has been shown to depend on the presence of probe distractors, a finding that has been traditionally seen to support the episodic retrieval model of negative priming; however, facilitated prime-to-probe contingency learning might also underlie this effect. In four sound identification experiments, the role of probe distractor interference in auditory negative priming was investigated. In each experiment, a group of participants was exposed to probe distractor interference while another group ran the task in the absence of probe distractors. Experiments 1A, 1B, and 1C varied in the extent to which fast versus accurate responding was required. Between Experiments 1 and 2, the spatial cueing of the to-be-attended ear was varied. Whereas participants switched ears from prime to probe in Experiment 1, they kept a stable attentional focus throughout Experiment 2. For trials with probe distractors, a negative priming effect was present in all experiments. For trials without probe distractors, the only ubiquitous after-effect of ignoring a prime distractor was an increase of prime response errors in ignored repetition compared to control trials, indicating that prime response retrieval processes took place. Whether negative priming beyond this error increase was found depended on the stability of the attentional focus. The findings suggest that several mechanisms underlie auditory negative priming with the only robust one being prime response retrieval.

Negative priming persists in the absence of response-retrieval

The hypothesis that retrieval of the prime response is responsible for the negative priming (NP) effect has gained popularity in recent studies of visual identity NP. In the current study we report an experiment in which we aimed to remove the response from the prime memory trace by means of spatio-temporal separation. Compared to an identical experiment without this separation (Ihrke et al., 2011), we find that the response-retrieval-specific interaction is absent indicating that the separation was successful in preventing response-retrieval. Still, both negative and positive priming are present as main effects which show that processes other than response-retrieval can produce NP. In addition, based on recordings of the eye-movements during task processing, we localize the NP effect in a target-selection process while positive priming manifests in facilitated response-selection. Our results are in line with a multiple-route view of NP.

Integrating the Irrelevant Sound

A distractor can be integrated with a target response and the subsequent repetition of the distractor can facilitate or hamper responding depending on whether the same or a different response is required, a phenomenon labeled distractor-response binding. In two experiments we used a priming paradigm with an identification task to investigate influences of stimulus grouping on the binding of irrelevant stimuli (distractors) and responses in audition. In a grouped condition participants heard relevant and irrelevant sounds in one central location, whereas in a non-grouped condition the relevant sound was presented to one ear and the irrelevant sound was presented to the other ear. Distractor-based retrieval of the prime response was stronger for the grouped compared to the non-grouped presentation of stimuli indicating that binding of irrelevant auditory stimuli with responses is modulated by perceptual grouping.

Automatic generation of randomized trial sequences for priming experiments

In most psychological experiments, a randomized presentation of successive displays is crucial for the validity of the results. For some paradigms, this is not a trivial issue because trials are interdependent, e.g., priming paradigms. We present a software that automatically generates optimized trial sequences for (negative-) priming experiments. Our implementation is based on an optimization heuristic known as genetic algorithms that allows for an intuitive interpretation due to its similarity to natural evolution. The program features a graphical user interface that allows the user to generate trial sequences and to interactively improve them. The software is based on freely available software and is released under the GNU General Public License.