Variability in response criteria affects estimates of conscious identification and unconscious semantic priming

Three experiments examined the role of response criteria in a masked semantic priming paradigm using an exclusion task. Experiment 1 used on-line prime-report (“report the prime if you saw it”) and exclusion instructions in which participants were told to avoid completing a word stem (e.g. mo—) with a word related to a prime (e.g. cash) flashed for 0, 38 or 212 ms. Semantic priming (i.e. exclusion failure) was significant in the items analysis, but was moderated by peoples’ ability to report the prime in the participant analysis. Prime-report thresholds in Experiment 2 were made more liberal by instructing participants to guess on every trial. Prime-report increased from Experiment 1 as exclusion failures were eliminated. Experiment 3 clarified the relationship between awareness and prime identification using an on-line measure of confidence and different liberal prime report instructions. The current findings suggest that the ability to act upon (via exclusion performance) and report information in a masked prime is determined by a variable response criterion, which can be manipulated as an independent variable.     

Implicit working memory

Working Memory (WM) plays a crucial role in many high-level cognitive processes (e.g., reasoning, decision making, goal pursuit and cognitive control). The prevalent view holds that active components of WM are predominantly intentional and conscious. This conception is oftentimes expressed explicitly, but it is best reflected in the nature of major WM tasks: All of them are blatantly explicit. We developed two new WM paradigms that allow for an examination of the role of conscious awareness in WM. Results from five studies show that WM can operate unintentionally and outside of conscious awareness, thus suggesting that the current view should be expanded to include implicit WM.     

Evaluative priming from subliminal emotional words: Insights from event-related potentials and individual differences related to anxiety

The present ERP study investigated effects of subliminal emotional words on preference judgments about subsequent visual target stimuli (paintings, portraits). Each target was preceded by a masked 17-ms emotional adjective. Four classes of prime words were distinguished according to the combinations of positive/negative valence and high/low arousal. Targets were liked significantly more after positive-arousing primes (e.g., happy), relative to negative-arousing (brutal), positive-nonarousing (mild), and negative-nonarousing primes (lazy). In the target ERP, amplitude of right-hemisphere positive slow wave was increased after positive-arousing compared to negative-arousing primes. Evaluative priming effects on judgments and ERPs were more pronounced in high state-anxious participants. The results suggest that (1) there is indeed affective/semantic processing of unconscious words, (2) evaluative priming operates relatively late during target processing, (3) to be effective, prime words need to score high on the arousal dimension, and (4) individual differences in state anxiety modulate the susceptibility to subliminal evaluative priming.     

The nonconscious road to perceptions of performance: Achievement priming augments outcome expectancies and experienced self-agency

Three experiments explored the effects of priming the achievement concept on the expectation of performance outcomes and experiences of self-agency over outcomes in a task in which performance outcomes were dependent on chance. Experiment 1 and 2 showed that achievement priming produced expectations of higher (more successful) outcomes prior to working on the task, regardless of whether priming was subliminal (nonconscious) or supraliminal (conscious) and that this effect could not be attributed to subjective motivation to perform well. Experiment 3 revealed that subliminal achievement priming decreased participants’ experienced self-agency when outcome feedback was low, but increased self-agency when it was high. Together, these results suggest that activating achievement concepts outside of awareness spontaneously triggers expectations of higher task outcomes, which increases or decreases self-agency depending on whether there is a match or mismatch with observed outcomes. Implications for the literature on achievement-priming effects on behavior are discussed.     

Faster might not be better: Pictures may not elicit a stronger unconscious priming effect than words when modulated by semantic similarity

It has been suggested that unconscious semantic processing is stimulus-dependent, and that pictures might have privileged access to semantic content. Those findings led to the hypothesis that unconscious semantic priming effect for pictorial stimuli would be stronger as compared to verbal stimuli. This effect was tested on pictures and words by manipulating the semantic similarity between the prime and target stimuli. Participants performed a masked priming categorization task for either words or pictures with three semantic similarity conditions: strongly similar, weakly similar, and non-similar. Significant differences in reaction times were only found between strongly similar and non-similar and between weakly similar and non-similar, for both pictures and words, with faster overall responses for pictures as compared to words. Nevertheless, pictures showed no superior priming effect over words. This could suggest the hypothesis that even though semantic processing is faster for pictures, this does not imply a stronger unconscious priming effect.     

Probing the influence of unconscious fear-conditioned visual stimuli on eye movements

Efficient threat detection from the environment is critical for survival. Accordingly, fear-conditioned stimuli receive prioritized processing and capture overt and covert attention. However, it is unknown whether eye movements are influenced by unconscious fear-conditioned stimuli. We performed a classical fear-conditioning procedure and subsequently recorded participants’ eye movements while they were exposed to fear-conditioned stimuli that were rendered invisible using interocular suppression. Chance-level performance in a forced-choice-task demonstrated unawareness of the stimuli. Differential skin conductance responses and a change in participants’ fearfulness ratings of the stimuli indicated the effectiveness of conditioning. However, eye movements were not biased towards the fear-conditioned stimulus. Preliminary evidence suggests a relation between the strength of conditioning and the saccadic bias to the fear-conditioned stimulus. Our findings provide no strong evidence for a saccadic bias towards unconscious fear-conditioned stimuli but tentative evidence suggests that such an effect may depend on the strength of the conditioned response.     

On the benefits of thinking unconsciously: Unconscious thought can increase post-choice satisfaction

This work compares conscious thought and unconscious thought in relation to quality of choice. Earlier work [Dijksterhuis, A. (2004). Think different: The merits of unconscious thought in preference development and decision making. Journal of Personality and Social Psychology, 87, 586-598] has shown that people make better choices after engaging in unconscious thought (i.e., unconscious activity during a period of distraction) rather than in conscious thought. However, the evidence was obtained for choices between hypothetical alternatives with quality of choice operationalized normatively. As quality of decision is essentially subjective, in the current experiment participants chose between real objects with quality operationalized as post-choice satisfaction. In a paradigm based on work by Wilson and colleagues [Wilson, T. D., Lisle, D., Schooler, J. W., Hodges, S. D., Klaaren, K. J., & LaFleur, S. J. (1993). Introspecting about reasons can reduce post-choice satisfaction. Personality and Social Psychology Bulletin, 19, 331-339], participants were briefly presented with five art posters, and chose one either (a) immediately, (b) after thorough conscious thinking about each poster, or (c) after a period of distraction. Participants took their favorite poster home and were phoned 3-5 weeks later. As hypothesized, unconscious thinkers were more satisfied with their choice than participants in the other two conditions.     

Examining effects of preconscious mere exposure: An inattentional blindness approach

An increase in affective preference for stimuli, which a person has been repeatedly exposed to, is known as mere exposure effect. This effect has been shown for stimuli that are processed subliminally, that is, below the threshold of awareness. This study fills a current research gap by investigating mere exposure effects under processing that is preconscious, which follows from a high stimulus strength but absence of top-down amplification. In three experiments (N = 240 in total) preconscious processing was evoked using an inattentional blindness paradigm, which allowed the processing of stimuli (nonwords or Chinese symbols) under complete inattention. Contrary to our hypothesis, we did not find a mere exposure effect in our experiments. We expand the current state of knowledge by discussing the distractor devaluation effect and the attentional set of participants as possible reasons for the absence of the mere exposure effect. Directions for future investigations are outlined.     

Unconscious attention modulates the silencing effect of top-down predictions

The brain is considered to be proactive in that it continuously generates predictions about external environment stimuli. Recent Bayesian models of perception have demonstrated that prediction and attention operate synergistically to optimize stimulus processing. However, the relation between prediction and unconscious attention remains unclear given the relative neglect of unconscious attention in scholarly literatures. To investigate this issue, twenty participants (12 women) performed an orientation identification task in which a circular grating appeared either in the left or in the right visual field in a single 30–40 min session, during which 64-channel EEG data were acquired. Behavioral results showed an unconscious-attended effect and a facilitated effect. Importantly, prediction-related P1 and N1 silencing effects were observed in the unconscious-attended condition, probably reflecting that unconscious attention improves the precision of top-down predictions at an early stage of processing, thereby increasing the synaptic gain of predictor neurons. Moreover, unlike the early ERP components, P3 revealed a reversed pattern of results, which displayed a silencing effect of prediction only in the unattended condition, suggesting that the influence of unconscious attention on the silencing effect may change over time.     

Identifying words that emerge into consciousness: Effects of word valence and unconscious previewing

Words with negative valence capture attention and this increase in attentional resources typically enhances perceptual processing. Recently, data using continuous flash suppression (CFS) appear to contradict this. In prior research when Chinese words were unconsciously presented in CFS and contrast was raised until the word was identified, RTs to identify words with negative valence were slower than RTs to words with neutral valence. This result might be limited to situations where a logographic writing system is used and could reflect a type of cognitive aftereffect where previewing the word causes habituation. Data (N = 60) indicate that results generalize from a logographic (Chinese) to an orthographic writing system (English). In addition, when words were previewed in CFS RTs were slowed for words with negative valence relative to words with neutral valence and this was reversed when words were shown binocularly. Implications for theories of unconscious word processing and cognitive aftereffects are discussed.