Detection of concealed knowledge via the ERP-based technique Brain Fingerprinting: Real-life and real-crime incidents.

Brain Fingerprinting (BFP) is an electroencephalogram-based system used to detect knowledge, or absence of knowledge of a real-life incident (e.g., a crime) in a person's memory. With the help of BFP, a potential crime suspect can be classified as possessing crime-related information (Information-Present), not possessing crime-related information (Information-Absent), or Indeterminate (BFP unable to classify a subject). In the lab setting, we compare the ground-truth of a subject (i.e., real-life involvement in an incident) against their classification based on BFP testing. We report two studies: replication of BFP with university students (Study 1) and replication of BFP with parolees (Study 2). In Study 1, we tested 31 subjects (24 females, seven males, mean age = 21.3) on either their own or another subject's real-life incident. BFP correctly classified nine Information-Present and 18 Information-Absent subjects, but with one false positive and three exclusions. In Study 2, we tested 17 male parolees (mean age = 47.5) on their own or another parolee's crime incident. BFP correctly classified two Information-Present and six Information-Absent subjects. However, there was also one false positive classification and three Indeterminates. Additionally, we identified three subjects who could not complete the BFP testing and two exclusions. We posit that BFP is not yet at a stage to be considered a robust and accurate crime-detection tool as claimed in former articles. Nevertheless, after addressing the limitations, BFP has considerable potential as an information detection tool in forensic investigations, especially for detecting idiosyncratic crime-relevant knowledge in a perpetrator, in addition to helping to confirm the accuracy of a suspect's claim of innocence.

Reversal of typical processing dynamics in positive and negative priming using a non-dominant to dominant cross-language lexical manipulation.

A bilingual primed lexical decision task was used to investigate priming effects produced by attended and ignored words. Participants were required to name prime target words in their weaker (L2) language and then make lexical decisions to probe target items in their dominant (L1) language. Accelerated lexical decisions to probe target words resulted when the word was a translation equivalent of the preceding prime target word, but they were not impaired when the word was a translation equivalent of the preceding ignored nontarget word. This novel finding of a positive priming effect coupled with the absence of a negative priming effect is the opposite pattern of earlier cross-language experiments wherein priming was assessed from L1 to L2 [i.e., Li, Neumann, & Chen, 2017. Identity and semantic negative priming in rapid serial visual presentation streams. Attention, Perception & Psychophysics, 79, 1755-1776; Neumann, McCloskey, & Felio, 1999. Cross-language positive priming disappears, negative priming does not: evidence for two sources of selective inhibition. Memory & Cognition, 27, 1051-1063; Nkrumah & Neumann, 2018. Cross-language negative priming remains intact, while positive priming disappears: evidence for two sources of selective inhibition. Journal of Cognitive Psychology, 3, 1-12]. The present results may be a reflection of altered excitatory and inhibitory dynamics when a weaker, non-dominant language is the source for potential positive and negative priming effects between languages in bilinguals.

Positive and negative priming differences between short-term and long-term identity coding of word-specific attentional priorities.

Two experiments investigated positive priming and negative priming effects in a lexical decision task. A priming task was used in which participants were required to make a verbal naming response to a prime target word, flanked by a distractor word, followed by a lexical decision response to a probe target word or nonword, flanked by a distractor word. The longevity of both positive and negative priming was explored in short-lag and long-lag conditions in which stimuli were presented once and only once, except in order to fulfill the priming manipulations. The results showed significant immediate positive priming and negative priming effects, but only negative priming was sustained for over 8 minutes with many intervening trials, whereas there was no evidence of positive priming after the same delay. These intriguing results have implications for the nature of inhibitory processing and differing predictions between inhibition-based and episodic retrieval accounts of priming.

Excitatory and inhibitory priming by attended and ignored non-recycled words with monolinguals and bilinguals.

Experiments examining identity priming from attended and ignored novel words (words that are used only once except when repetition is required due to experimental manipulation) in a lexical decision task are reported. Experiment 1 tested English monolinguals whereas Experiment 2 tested Twi (a native language of Ghana, Africa)-English bilinguals. Participants were presented with sequential pairs of stimuli composed of a prime followed by a probe, with each containing two items. The participants were required to name the target word in the prime display, and to make a lexical decision to the target item in the probe display. On attended repetition (AR) trials the probe target item was identical to the target word on the preceding attentional display. On ignored repetition (IR) trials the probe target item was the same as the distractor word in the preceding attentional display. The experiments produced facilitated (positive) priming in the AR trials and delayed (negative) priming in the IR trials. Significantly, the positive and negative priming effects also replicated across both monolingual and bilingual groups of participants, despite the fact that the bilinguals were responding to the task in their non-dominant language.

Identity and semantic negative priming in rapid serial visual presentation streams.

In selective attention tasks, the efficiency of processing concurrently presented target and distractor stimuli in a given display is often influenced by the relationship these stimuli have with those in the previous display. When a to-be-attended target on a current trial (the probe trial) matches the ignored, non-target distractor on a previous trial (the prime trial), a response to the target is typically delayed compared with when the two stimuli are not associated. This negative priming (NP) phenomenon has been observed in numerous studies with traditional NP tasks presenting the target and distractor simultaneously in both the prime and probe trial couplets. Here, however, in four experiments using a mixture of stimulus types (letters, digits, English number words, and logographic Chinese number words), target and distractor stimuli were temporally separated in two rapid serial visual presentation (RSVP) streams instead of concurrently presented. The findings provide a conceptual replication and substantial extension of a recent study by Wong (Plos One, 7, e37023, 2012), and suggest that active suppression of irrelevant distracting information is a more ubiquitous form of cognitive control than previously thought.

Comparing Repetition Priming Effects in Words and Arithmetic Equations: Robust Priming Regardless of Color or Response Hand Change.

Previous studies have shown that stimulus repetition can lead to reliable behavioral improvements. Although this repetition priming (RP) effect has been reported in a number of paradigms using a variety of stimuli including words, objects, and faces, only a few studies have investigated mathematical cognition involving arithmetic computation, and no prior research has directly compared RP effects in a linguistic task with an arithmetic task. In two experiments, we used a within-subjects design to investigate and compare the magnitude of RP, and the effects of changing the color or the response hand for repeated, otherwise identical, stimuli in a word and an arithmetic categorization task. The results show that the magnitude of RP was comparable between the two tasks and that changing the color or the response hand had a negligible effect on priming in either task. These results extended previous findings in mathematical cognition. They also indicate that priming does not vary with stimulus domain. The implications of the results were discussed with reference to both facilitation of component processes and episodic memory retrieval of stimulus-response binding.

Novel word processing.

People who text messages often shorten words by eliminating internal letters (e.g., "climate, clmte"). Although these novel representations (i.e., subset word forms) are not true words, sentence context may prime semantic activation. We hypothesized that if participants are presented with a context sentence prime containing a subset form target word, then participants' performance should improve when the stimulus is presented to the left visual field/right hemisphere (LVF/RH) because the RH is less reliant on correct orthography than the left hemisphere (LH). We also hypothesized that participants' bias of processing novel stimuli is a function of visual field and hemisphere presentation. The results supported the hypothesis. When participants were shown subset word forms in the LVF/RH, their accuracy was significantly greater than when they were shown in the RVF/LH. Additionally, signal detection theory was applied to the results and substantiated the findings that participants' bias toward processing subset and orthographically correct words is a function of visual field and hemisphere presentation.

Text-speak processing impairs tactile location.

Dual task experiments have highlighted that driving while having a conversation on a cell phone can have negative impacts on driving (Strayer & Drews, 2007). It has also been noted that this negative impact is greater when reading a text-message (Lee, 2007). Commonly used in text-messaging are shortening devices collectively known as text-speak (e.g.,Ys I wll ttyl 2nite, Yes I will talk to you later tonight). To the authors' knowledge, there has been no investigation into the potential negative impacts of reading text-speak on concurrent performance on other tasks. Forty participants read a correctly spelled story and a story presented in text-speak while concurrently monitoring for a vibration around their waist. Slower reaction times and fewer correct vibration detections occurred while reading text-speak than while reading a correctly spelled story. The results suggest that reading text-speak imposes greater cognitive load than reading correctly spelled text. These findings suggest that the negative impact of text messaging on driving may be compounded by the messages being in text-speak, instead of orthographically correct text.

Text-speak processing and the sustained attention to response task.

We examined performance in a sustained attention to response task (SART) (Experiment 1) and a more traditionally formatted vigilance task (Experiment 2) using novel word stimuli (text-speak) and normally spelt words. This enabled us to address whether the SART is a better measure of sustained attention or of response strategy, and to investigate the cognitive demands of text-speak processing. In Experiment 1, 72 participants completed a subset (text-speak) and a word SART, as well as a self-reported text experience questionnaire. Those who reported more proficiency and experience with text-speak made more errors on the subset SART, but this appeared to be due to their increase in response speed. This did not occur in the word SART. In Experiment 2, 14 participants completed high No-Go, low-Go (more traditional response format) versions of these tasks to further investigate the cognitive demands of text-speak processing. Response latency increased over periods of watch only for the text-speak task, not for the word task. The results of Experiment 1 support the perspective that the SART is highly sensitive to response strategy, and the results of both experiments together indicate target detection tasks may be a novel way of investigating the cognitive demands of text-speak processing.

Classic Stroop Negative Priming effects for children and adults diverge with less-conflicting and nonconflicting conditions.

Negative priming indexes an inhibition process that aids target selection by reducing distractor interference. To date, children have produced negative priming only in tasks where distractor response tendencies are consistently greater than or equal to targets and not in tasks containing a substantial proportion of low-conflict distractors. To establish the exact parameters under which children's negative priming attenuates relative to adults, we varied processing demands across 2 experiments involving children and adults. Negative priming was comparable when 100% high-conflict conditions were encountered (Experiment 1) and was intact in adults but not children when a ratio of 50:50 high- to low-conflict conditions was encountered (Experiment 2). Compared with adults, children seem induced to divide attention more generally when low-conflict attentional conditions are included, attenuating negative priming.

Avoiding the potential pitfalls of using negative priming tasks in developmental studies: assessing inhibitory control in children, adolescents, and adults.

Despite being ignored, visual distractors often produce traceable negative priming (NP) effects that can be used to investigate inhibitory processes. Robust NP effects are typically found with young adults, but not with children. Using 2 different NP tasks, the authors compared NP in 5 different age groups spanning 5 to 25 years of age. The 1st task revealed comparable NP between all age groups, but a linear decrease in NP through childhood to early adulthood. In the 2nd task, NP decreased linearly into adulthood, with children actually showing larger NP than adults. This Age Group ? NP interaction was eliminated, however, when reaction time data were log transformed to control for age differences in overall processing speed. When appropriately transformed data were used, both experiments showed that NP was intact and comparable between children, adolescents, and adults, and suggested that an inhibitory process is fully developed by early childhood. The results highlight how potential pitfalls might be avoided when comparing NP in children and adults.

Selective attention and inhibitory deficits in ADHD: does subtype or comorbidity modulate negative priming effects?

Selective attention has durable consequences for behavior and neural activation. Negative priming (NP) effects are assumed to reflect a critical inhibitory component of selective attention. The performance of adolescents with Attention Deficit/Hyperactivity Disorder (ADHD) was assessed across two conceptually based NP tasks within a selective attention procedure. Comorbidity (non-comorbid ADHD vs. comorbid ADHD) and subtype (ADHD combined vs. ADHD inattentive) were considered key issues. Results found NP effects to differ as a function of comorbidity but not subtype. Findings are discussed in light of functional neuroimaging evidence for neuronal enhancement for unattended stimuli relative to attended stimuli that strongly complements an inhibitory-based explanation for NP. Implications for the 'AD' in ADHD and contemporary process models of the disorder are considered.

Interference and negative priming effects in adolescents with attention deficit hyperactivity disorder.

Three visual selective attention tasks were used to measure potential differences in susceptibility to interference and inhibitory cognitive control processes in 16 adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) and 45 similar-aged controls. Susceptibility to interference was assessed using the Stroop color and word naming test. Efficiency of distractor inhibition was assessed in two conceptual negative priming tasks. The majority of studies in this area indicate that people with ADHD demonstrate higher levels of interference and lower negative priming effects in comparison with age-matched peers. However, we found that although the ADHD group was consistently slower to name target stimuli than the control group, there were no differences in interference or negative priming between the two groups.

Negative priming effects in children engaged in nonspatial tasks: evidence for early development of an intact inhibitory mechanism.

Three experiments are reported that examined conceptual negative priming effects in children 5 to 12 years of age. Experiment 1 used a negative priming variant of a flanker task requiring the naming of a central color blob flanked by irrelevant distractors. Experiment 2 used a negative priming variant of the Stroop color-word task. Experiment 3 used a same-different matching task with novel 3-D shapes. Results revealed significant and equivalent magnitudes of negative priming across the tested age groups for all 3 tasks. It is concluded that the inhibitory mechanism underlying conceptual (i.e., identity or semantic) negative priming in visual selective attention tasks is intact in young children. Because the findings and conclusions diverge from the developmental literature on negative priming, the authors attempt to reconcile the contradictions by pinning down the reasons for the discrepancies.