Physical effort modulates perceptual awareness judgment independent of level of processing.

Recent studies have emphasized the association between action and perceptual awareness, suggesting that action-related information can contribute to perceptual awareness. Given that the Level of Processing (LoP) hypothesis proposes that the emergence of awareness depends on the level of stimulus processing, the current study examines whether action impacts perceptual awareness across different processing levels. In Experiment 1, participants identified target stimuli's color (low-level task) or category (high-level task) via mouse clicks, followed by visual awareness ratings. Experiment 2 replicated the tasks using hand-grip dynamometers. Results from Experiment 1 support the LoP theory, showing a more gradual emergence of awareness for low-level features and a more dichotomous emergence for high-level features. In Experiment 2, higher reported visual awareness ratings were observed at greater physical effort, regardless of task type. These results suggest that action-related information influences reported awareness of stimuli in the same way at low- and high-level stimulus processing.

Short-term retention of words as a function of encoding depth.

The traditional short- and long-term storage view of information processing and the levels-of-processing view both discuss the forgetting of information over time. In the traditional stage view, there is loss of at least poorly encoded information across several seconds when the information cannot be rehearsed (e.g., Ricker et al., 2020, Learning, Memory, and Cognition, 46, 60-76). In the levels-of-processing approach, information that is encoded in a shallow manner is lost more quickly over time than deeply-encoded information (Craik & Lockhart, 1972, Journal of Verbal Learning and Verbal Behavior, 11, 671-684.). Previous studies of the depth of encoding, however, have mostly been conducted using delayed tests, so there are few studies directly comparing the rate of forgetting over time for information as a function of different depths of encoding. We manipulated the level of processing with immediate recall in a modified Brown-Peterson task. An effect of the level of processing was robust, but evidence of forgetting across retention intervals was not always observed. When encoding time was curtailed (in Experiments 3 and 4), we found main effects of both the level of processing and the retention interval, but no interaction between the two variables. The results suggest that the depth-of-encoding effect may occur during the initial encoding of items, but without differential forgetting within the range of retention intervals that we examined (0-18 s), in contrast to the suggestion by Craik and Lockhart. Further work is needed to determine whether the depth-of-processing effect would grow over longer intervals.

Effect of levels-of-processing on rates of forgetting.

The levels-of-processing (LOP) framework, proposing that deep processing yields superior retention, has provided an important paradigm for memory research and a practical means of improving learning. However, the available levels-of-processing literature focuses on immediate memory performance. It is assumed within the LOP framework that deep processing will lead to slower forgetting than will shallow processing. However, it is unclear whether, or how, the initial level of processing affects the forgetting slopes over longer retention intervals. The present three experiments were designed to explore whether items encoded at qualitatively different LOP are forgotten at different rates. In the first two experiments, depth of processing was manipulated within-participants at encoding under deep and shallow conditions (semantic vs. rhyme judgement in Experiment 1; semantic vs. consonant-vowel pattern decision in Experiment 2). Recognition accuracy (d prime) was measured between-participants immediately after learning and at 30-min, 2-h, and 24-h delays. The third experiment employed a between-participants design, contrasting the rates of forgetting following semantic and phonological (rhyme) processing at immediate, 30-min, 2-h, and 6-h delays. Results from the three experiments consistently demonstrated a large effect size of levels of processing on immediate performance and a medium-to-large level effect size on delayed recognition, but crucially no LOP × delay group interaction. Analysis of the retention curves revealed no significant differences between the slopes of forgetting for deep and shallow processing. These results suggest that the rates of forgetting are independent of the qualitatively distinct encoding operations manipulated by levels of processing.

An examination of individual differences in levels of processing.

The present study examined individual differences in levels of processing. Participants completed a cued recall task in which they made either rhyme or semantic judgements on pairs of items. Pupillary responses during encoding were recorded as a measure of the allocation of attentional effort and participants completed multiple measures of working and long-term memory. The results suggested levels of processing effect in both accuracy and pupillary responses with deeper levels of processing demonstrating higher accuracy and larger pupillary responses than shallower levels of processing. Most participants demonstrated levels of processing effect, but there was substantial variability in the size of the effect. Variation in levels of processing was positively related to individual differences in long-term memory and the magnitude of the pupillary levels of processing effect, but not working memory. These results suggest that some of the variation in levels of processing is likely due to individual differences in the allocation of attentional effort (particularly to items processed deeply) during encoding.

Encoding-phase orientation toward thematic content over perceptual style benefits picture memory.

Orienting toward the meaning versus perceptual features of an experience benefits subsequent memory. Yet given that past work encouraged these orientations with different tasks, it is not clear if this memory benefit is solely due to internal processing factors versus external task-related ones. Moreover, it remains unclear how this benefit generalises from verbal to detailed picture memory. Here, we developed a novel paradigm that cued participants' attention to thematic (story) or stylistic (artist style) dimensions of storybook-style illustrations during a repeat-detection task. Afterwards, participants completed a recognition memory test with studied illustrations and lures along thematic and stylistic dimensions. In contrast to past work, both orienting tasks were identical except for the dimension participants were cued to attend to. Furthermore, our thematic and stylistic dimensions enabled us to separately examine memory quality along each dimension. We found that thematic attention yielded superior memory for studied illustrations over stylistic orientations. False alarms to lures varied by dimension and attention: errors were greater to thematic than stylistic lures overall and stylistic attention elevated false alarms to stylistic lures. Our results show that semantic encoding orientations enhance detailed picture memory, without a cost to memory quality along semantic or perceptual dimensions of experience.

A thorough examination of cue specificity and task-appropriateness in defining focal and nonfocal prospective memory tasks.

Prospective memory (PM) - memory for future intentions - has a core term called focality which describes how closely a PM task relates to an ongoing task. When a close relationship exists between an ongoing and PM task, the task is classified as focal (loose relationships are classified as nonfocal). Competing PM theories differ primarily in explanations for how focality changes participants' approaches. Researchers classify PM intentions as focal or nonfocal in two ways: (1) task appropriateness, congruency (TAP) or incongruency (TIP) of processing to complete both tasks, and (2) cue specificity, specific or general task cues. Independently manipulating this ambiguity in defining "focality" was our current focus. Participants were randomly assigned to a control group, a focal PM condition, or one of three nonfocal conditions. Their ongoing task involved a semantic judgment (Experiment 1) or an orthographic judgment (Experiment 2). Cue specificity impacted PM accuracy consistently, favouring specific cues. Task-appropriateness impacted PM accuracy in Experiment 1, but not in Experiment 2 which showed protective effects for specific, whole-word PM cues - emphasizing the role that deeper processing has on PM success. These studies highlight the ambiguity in the operational definition of focality and provide the groundwork for continued refinement of the definition.

Concreteness and levels of processing: a test of the dual-coding hypothesis using dynamic visual noise.

Concreteness and levels of processing (LOP) effects have been attributed to the differential availability of visual images for concrete words, and at deeper levels of processing, respectively. Interestingly, the concreteness effect has been shown to disappear under conditions involving dynamic visual noise (DVN), which is thought to suppress the generation of visual images from long-term memory. The present study further investigated the role of visual imagery in concreteness and LOP effects. Across four experiments, DVN was manipulated during study, and participants' memory for concrete and abstract words was measured using recall and recognition tests. Although some support for dual-coding was found, concreteness and LOP effects were not fully explained by visual imagery because they were present under DVN conditions. We conclude that concreteness and LOP effects may be better explained by an "extended dual-coding theory" that incorporates the role of context availability in accounting for this pattern of results.

The mystery of emotional mimicry: multiple functions and processing levels in expression imitation.

Mimicry of appearance or of facial, vocal, or gestural expressions emerges frequently among members of different species. When such mimicry directly relates to affective aspects of an interaction, researchers talk about "emotional mimicry". Emotional mimicry has been amply documented but its functionality is still debated. Why and when do people mimic the expressions of others, who benefits, the mimicker or the mimicked, and how do they benefit? Which processes underlie emotional mimicry? Is it completely automatic and unconscious or can it be deliberate and conscious? The current Theory Section addresses these questions from different theoretical perspectives. The invited article by Hess and Fischer focused on the role of mimicry in social regulation and social bonding. The invited comment by Krets and Akyüz highlights information gathering and prediction in social interaction. The invited comment by Bernhold and Giles emphasizes vocal communication and its role in interpersonal accommodation. In this editorial, I propose the different theoretical perspectives may be integrated by assuming a multilevel appraisal and response generation mechanism. I also suggest that emotional mimicry research may be broadened by including social learning, vocal imitation, interspecies comparisons, and affective computing approaches.

Levels of Processing Affect Perceptual Features in Visual Associative Memory.

The levels of processing (LOP) account has inspired thousands of studies with verbal material. The few studies investigating levels of processing with nonverbal stimuli used images with nameable objects that, like meaningful words, lend themselves to semantic processing. Thus, nothing is known about the effects of different levels of processing on basic visual perceptual features, such as color. Across four experiments, we tested 187 participants to investigate whether the LOP framework also applies to basic perceptual features in visual associative memory. For Experiments 1 and 2, we developed a paradigm to investigate recognition memory for associations of basic visual features. Participants had to memorize object-color associations (Experiment 1) and fractal-color associations (Experiment 2, to suppress verbalization). In Experiments 3 and 4, we extended our account to cued recall. All experiments revealed reliable LOP effects for basic perceptual features in visual associative memory. Our findings demonstrate that the LOP account is more universal than the current literature suggests.

Remembering: An Activity of Mind and Brain.

I present the case for viewing human memory as a set of dynamic processes rather than as structural entities or memory stores. This perspective stems largely from the construct of levels of processing, reflecting work I published with Robert Lockhart and with Endel Tulving. I describe the personal and professional contexts in which these and other ideas evolved, and I discuss criticisms of the ideas and our responses to critics. I also show how later versions of a processing approach to memory may fit with current findings and theories in memory research. In related work I have been involved in studies of cognitive aging, and I describe some theoretical and empirical points deriving from this aspect of my research efforts. Finally, I deal briefly with some experiments and reflections on divided attention, consolidation, and bilingualism and touch upon the neural bases of a processing approach.

Gradedness of visual awareness depends on attentional scope: Global perception is more graded than local perception.

The gradedness or discreteness of our visual awareness has been debated. Here, we investigate the influence of spatial scope of attention on the gradedness of visual awareness. We manipulated scope of attention using hierarchical letter-based tasks (global: broad scope; local: narrow scope). Participants reported the identity of a masked hierarchical letter either at the global level or at the local level. We measured subjective awareness using the perceptual awareness scale ratings and objective performance. The results indicate more graded visual awareness (lesser slope for the awareness rating curve) at the global level compared to the local level. Graded perception was also observed in visibility ratings usage with global level task showing higher usage of the middle PAS ratings. Our results are in line with the prediction of level of processing hypothesis and show that global/local attentional scope and contextual endogenous factors influence the graded nature of our visual awareness.

Visual awareness and the levels of processing hypothesis: A critical review.

Does a visual percept emerge to consciousness in a graded manner (i.e. evolving through increasing degrees of clarity), or according to a dichotomous, "all-or-none" pattern (i.e. abruptly transitioning from unawareness to awareness)? The level of processing hypothesis (LoP; B. Windey and A. Cleeremans, 2015) recently proposed a theoretical framework where the transition from unaware to aware visual experience is graded for low-level stimulus representations (i.e. stimulus "energy" or "feature" levels) whereas it is dichotomous for high-level (i.e. the perception of "letters", "words" or "meaning") stimulus perception. Here, we will critically review current behavioral and brain-based evidence on the LoP hypothesis and discuss potential challenges (such as differences in LoP conceptualizations, awareness scale related issues, attentional confounds and divergences on experimental factors or statistical analyses) which might be of use for future research within the field. Overall, the LoP hypothesis is a recent and promising proposal that attempts to integrate divergent evidence on the graded vs. dichotomous emergence of awareness debate. Whereas current evidence validates some of the assumptions proposed by the LoP account, there is still much work to do on both methodological and experimental levels. Future neuroimaging studies might help to disentangle the current complex pattern of results found in LoP studies and, importantly, shed some light on the ongoing debate about the search for the Neural Correlates of Consciousness (NCC).

Multiple species of distinctiveness in memory? Comparing encoding versus statistical distinctiveness on recognition.

The distinctiveness effect refers to the memorial benefit of processing unique or item-specific features of a memory set relative to a non-distinctive control. Traditional distinctiveness effects are accounted for based on qualitative differences in how distinctive items are encoded and subsequently retrieved. This study evaluates whether a separate species of distinctiveness - statistical distinctiveness - may provide an additional benefit to memory beyond traditional task-based processes. Statistical distinctiveness refers to the relative frequency with which a specific memory item or set is processed. The current study examined the presence of statistical distinctiveness through a series of levels-of-processing mixed groups in which related lists were studied using two of the following three tasks to promote either shallow ("E" identification), neutral (reading silently), or deep/distinctive (pleasantness ratings) processing followed by a recognition test. Participants studied lists in which these tasks were used frequently (80% of lists), equally (50% of lists), or infrequently (20% of lists). No recognition advantage was found when tasks were completed infrequently versus frequently. Instead, recognition was greatest for the deeper/more distinctive task - a pattern consistent with an encoding but not a statistical distinctiveness account.

The role of levels of processing in disentangling the ERP signatures of conscious visual processing.

We aimed to distinguish electrophysiological signatures of visual awareness from other task-related processes through manipulating the level of processing of visual stimuli. During an event-related EEG experiment, 36 subjects performed either color (low-level condition) or magnitude (high-level condition) evaluations of masked digits. Participants also assessed subjective visibility of each stimulus using the Perceptual Awareness Scale (PAS). Mean amplitude of the components of interest was analyzed (VAN - 140-240 ms; LP - 380-480 ms) with weighted regression mixed model. In the VAN component time window the mean amplitude correlated with PAS rating in both conditions. Mean amplitude in the LP time window correlated with PAS ratings in the high-level condition, but not in the low-level condition. Our results support the temporal unfolding of ERP makers of conscious processing, with an early component reflecting the initial perceptual experience and a late component being a correlate of the conscious experience of non-perceptual information.

The levels of perceptual processing and the neural correlates of increasing subjective visibility.

According to the levels-of-processing hypothesis, transitions from unconscious to conscious perception may depend on stimulus processing level, with more gradual changes for low-level stimuli and more dichotomous changes for high-level stimuli. In an event-related fMRI study we explored this hypothesis using a visual backward masking procedure. Task requirements manipulated level of processing. Participants reported the magnitude of the target digit in the high-level task, its color in the low-level task, and rated subjective visibility of stimuli using the Perceptual Awareness Scale. Intermediate stimulus visibility was reported more frequently in the low-level task, confirming prior behavioral results. Visible targets recruited insulo-fronto-parietal regions in both tasks. Task effects were observed in visual areas, with higher activity in the low-level task across all visibility levels. Thus, the influence of level of processing on conscious perception may be mediated by attentional modulation of activity in regions representing features of consciously experienced stimuli.

The role of long-term familiarity and attentional maintenance in short-term memory for timbre.

We study short-term recognition of timbre using familiar recorded tones from acoustic instruments and unfamiliar transformed tones that do not readily evoke sound-source categories. Participants indicated whether the timbre of a probe sound matched with one of three previously presented sounds (item recognition). In Exp. 1, musicians better recognised familiar acoustic compared to unfamiliar synthetic sounds, and this advantage was particularly large in the medial serial position. There was a strong correlation between correct rejection rate and the mean perceptual dissimilarity of the probe to the tones from the sequence. Exp. 2 compared musicians' and non-musicians' performance with concurrent articulatory suppression, visual interference, and with a silent control condition. Both suppression tasks disrupted performance by a similar margin, regardless of musical training of participants or type of sounds. Our results suggest that familiarity with sound source categories and attention play important roles in short-term memory for timbre, which rules out accounts solely based on sensory persistence.

Recognition Without Words: Using Taste to Explore Survival Processing.

Many educational demonstrations of memory and recall employ word lists and number strings; items that lend themselves to semantic organization and "chunking." By applying taste recall to the adaptive memory paradigm, which evaluates memory from a survival-based evolutionary perspective, we have developed a simple, inexpensive exercise that defies mnemonic strategies. Most adaptive memory studies have evaluated recall of words encountered while imagining survival and non-survival scenarios. Here, we've left the lexical domain and hypothesized that taste memory, as measured by recognition, would be best when acquisition occurs under imagined threat of personal harm, namely poisoning. We tested participants individually while they evaluated eight teas in one of three conditions: in one, they evaluated the toxicity of the tea (survival condition), in a second, they considered the marketability of the tea and, in the third, they evaluated the bitterness of the tea. After a filler task, a surprise recognition task required the participants to taste and identify the eight original teas from a group of 16 that included eight novel teas. The survival condition led to better recognition than the bitterness condition but, surprisingly, it did not yield better recognition than the marketing condition. A second experiment employed a streamlined design more appropriate for classroom settings and failed to support the hypothesis that planning enhanced recognition in survival scenarios. This simple technique has, at least, revealed a robust levels-of-processing effect for taste recognition and invites students to consider the adaptive advantages of all forms of memory.

From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing.

Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the activation pattern remains task-related LOP and is thus the result of a decision process as to which LOP to engage in.

Does level of processing affect the transition from unconscious to conscious perception?

Recently, Windey, Gevers, and Cleeremans (2013) proposed a level of processing (LoP) hypothesis claiming that the transition from unconscious to conscious perception is influenced by the level of processing imposed by task requirements. Here, we carried out two experiments to test the LoP hypothesis. In both, participants were asked to classify briefly presented pairs of letters as same or different, based either on the letters' physical features (a low-level task), or on a semantic rule (a high-level task). Stimulus awareness was measured by means of the four-point Perceptual Awareness Scale (PAS). The results showed that low or moderate stimulus visibility was reported more frequently in the low-level task than in the high-level task, suggesting that the transition from unconscious to conscious perception is more gradual in the former than in the latter. Therefore, although alternative interpretations remain possible, the results of the present study fully support the LoP hypothesis.

Reaction time as an outcome measure during online fear conditioning: Effects of number of trials, age, and levels of processing.

Recent studies have shown that fear conditioning experiments can be successfully conducted online. However, there is limited evidence that measures other than subjective ratings of threat expectancy can be collected, which means that online research may not be able to adequately replace laboratory experiments. In the current study, we conducted an online fear conditioning experiment consisting of habituation, acquisition, extinction and 48 h delayed extinction recall using ratings of threat expectancy and conditional stimulus pleasantness, and probe reaction time as outcome measures. The conditional stimuli were categories of words and a levels of processing manipulation explored whether words that were processed at a deeper level during extinction evoked smaller differential threat responses during extinction recall. Although the levels of processing manipulation did not produce a significant outcome, we found that extinction recall was successfully operationalised in our study. Reaction time indicated differential responding during both acquisition and extinction recall, and age of participants was correlated in one of two experiments with differential threat expectancy and reaction time, such that older participants showed better safety learning. The outcomes of this experiment provide multiple novel tools for researchers to explore fear conditioning, especially in an online environment.