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Anthony Marcel, A British psychologist, contributed to the early analysis of nonconscious perceptual processes in the early 1970s and the 1980s. Early on, Marcel's research regarding unconscious reading and ambiguous words gained attention. In 1983, his two publications addressing nonconscious perceptual processing in the same issue of Cognitive Psychology created a significant impact in the field. He notably used dichoptic Stimulus-Onset Asynchrony pattern masking and the Lexical Decision Task. His publications were met with enthusiasm as well as criticism. The experiments within the publications were the basis of hundreds of research publications that followed, as many attempted to replicate the findings with adopted techniques once the principle of nonconscious perception was confirmed and accepted. Marcel currently works at the University of Hertfordshire and Cambridge University, and interestingly, his current research focuses around consciousness.

1983 Publications
In the unconscious cognition field, Marcel is best known for his two publications in a 1983 Cognitive Psychology issue in which he demonstrated unconscious perception.

The first piece, an experimental paper, used five experiments with dichoptic masking, energy masking, Lexical Decision Task, and Stroop Effect to investigate perception without awareness. . In the second paper, Marcel conceptually makes the distinction between perceptual processing and awareness. . The conclusions, particularly the demonstration of nonconscious perception, gained much attention, even prior to the publication with references and papers provoked by the findings surfacing pre-publication.

Another major goal of the experiments was to investigate masking. Masking had been thought to interrupt, prevent or stop perceptual processing. Marcel distinguished the effects of energy masking and backward pattern masking.

Experiments
Experiment 1: Word-mask Stimulus-Onset Asynchrony was manipulated to measure differences in processing. Perceptions (similarity judgments) could be made at target-mask SOA levels too brief for detection of the pre-mask word.

Experiment 2: Similarity judgments were used again, however this time the masked word and the forced-choice stimuli covaried negatively in terms of association. The similarity judgments no longer indicated perception in this experiment, indicating passive judgments in experiment 1.

Experiment 3: A Stroop Effect test was used with color patches shown either preceded or accompanied by pattern masked words. Since the masking prevented awareness of primed words and facilitation occurred with color-congruent words (vs. color-incongruent), perception without awareness was demonstrated.

Experiment 4: Central (i.e. dichoptic) pattern masking and peripheral energy masking were contrasted in a Lexical Decision Task experiment with unmasked, energy masked, and pattern masked words. The association effect occurred equally with pattern masked and unmasked conditions, but not in the energy masking condition.

Experiment 5: Word+mask at SOAs just below word detection level were repeated, with an increase in number of repetitions showing an increase in associative facilitation effect but with no impact on awareness.

Generally, Lexical Decision Task used in the experiments had participants classify letter strings as either words (infant, street) or non-words (glayer, woot). Letter strings were classified faster when primed with related words (child with infant), demonstrating facilitation and thereby perception without awareness. Many replications have been attempted and successful since these findings, including experiments with various primes (e.g. photographs or objects and faces) and across presentation modality.

Pre-History
Work on nonconscious perception had previously been met with harsh criticism and rejection from academic psychologists, with much of the research using unreliable techniques. This academic rejection was coupled with unconscious processing having negative affiliations in society with subliminal persuasion and political brainwashing, causing the term subliminal to carry a stigma for some time.

Marcel was able to make an impact with his work primarily by placing his findings in the context of existing accepted cognitive work, thereby publishing in an appropriate journal and at the right time.

Marcel began research in this domain in the early 1970s, with his work initially rooted in reading. . Marcel's 1983 publication experiments were prompted by unexpected findings in masked reading tasks he had been running with school children. He noticed errors (e.g. king for queen, yellow for blue) that were not only impossible according to theories and the masking literature at the time, but suggestive of nonconscious perception (due to errors not having a graphic or phonological resemblance with the stimulus string, but a relation that was either associative or semantic). Also at that time, Marcel was working with neurological patients who showed Deep Dyslexia, and he was interested in their errors involving associatively or semantically related words (e.g. sleep for dream).

Prior work on Lexical Decision Task contributed to Marcel's use of the method in his experiments. Related words were shown to facilitate classification (The classic "butter" preceded by "bread" or "nurse" example) as well as the effects of interstimulus interval on this effect.

Marcel also researched the processing of polysemous words (e.g. difference in process of "palm" when preceded by masked word "wrist" vs. "tree"). This research showed qualitative differences between conscious and nonconscious perception of words with multiple meanings, namely that both meanings seemed to be simultaneously activated when presented nonconsiously, but only one meaning was activated at a time when presented consciously.

Post-Publication
Following the publications, Marcel's work and interpretations were met with enthusiasm as well as criticism. Most notably, Holender criticized all prior unconscious priming experiments in his 1986 publication, including demonstrations of indirect-without-direct effects found by Balota , Fowler et al. , and Marcel. Holender took issue with direct measures and claimed that establishing indirect effects in the absolute absence of direct effects was required in order to demonstrate SSA (subliminal semantic activation). This requirement is generally accepted as being too stringent, with the distinction between objective and subjective thresholds proposed by Cheesman and Merikle being more accepted and offering a more achievable demonstration of SSA. Their contribution also addressed Marcel's work, adding that Marcel later addressed the subjective threshold as being relevant and that the awareness threshold demonstrated in his 1983 work was likely a subjective rather than objective threshold.

Further, Holender also specifically criticized Marcel for claiming nonconscious semantic priming. This however, was not Marcel’s interpretation, as he did not claim to have evidence to support semantic effects, only associative effects.

Since the mid 1980s, hundreds of publications of research investigating nonconsious visual perception of various materials and its relation with conscious perception have methodologically been based on Marcel's and others' work. However, achieving equivalent methodologies to provide nonsconsious perception in audition, touch, smell, or proprioception has proved very difficult, with the most supporting data coming from various neurological patients who show nonconscious effects in the absence of equivalent conscious effects. The most relevant of such patients are those who show “Blindsight”, i.e. those who lack conscious vision of static stimuli in a retinotopic area of the visual field due to damage to primary visual cortex, but who show striking evidence of nonconscious perception of those same stimuli.

There has also been a significant increase in the level of interest in consciousness among psychologists, philosophers and neuroscientists since the mid 1980s.

Academic Career
Marcel was for many years at the Medical Research Council Applied Psychology Unit (later the MRC Cognition and Brain Sciences Unit) in Cambridge. Since 2005 he has been Professor of Psychology at the University of Hertfordshire (where he is now Emeritus) and has held a senior professorial research position in the Department of Experimental Psychology of Cambridge University. He is also a Senior Research Associate at the Institute of Philosophy at London University.

Anthony Marcel has recently been awarded a Fellowship of the Association for Psychological Science in recognition of his sustained outstanding contributions to the science of psychology.

Current Research
One of Marcel’s recent and current focuses in consciousness is on phenomenal experience, e.g. as in emotion experience. His research on neglect and anosognosia for hemiplegia has continued his work on lack of conscious awareness in neurological patients; currently he is investigating similarities between a subgroup of anosognosic patients whose anospognosia shows delusional phenomena and psychotic delusional patients. Beside his strictly empirical scientific work, he is also writing a book on irony, bringing together the psychology of irony and how it works in various imaginative artistic media (e.g. novels, theatre, film).

Recent Publications
Gallagher, S. and Marcel, A.J. (1999). The Self in Contextualized Action. Journal of Consciousness Studies, 6 (4), 4-30. (Reprinted in Models of the Self, Eds. Shaun Gallagher and Jonathan Shear, Thorverton, UK: Imprint Academic, 1999, 273-299.)

Lambie, J.A. & Marcel, A.J. (2002). Consciousness and Emotion Experience: A Theoretical Framework. Psychological Review, 109, 219-259.

Marcel, A.J. (1998). Blindsight and shape perception: deficit of visual consciousness or of visual function? Brain, 121 (8), 1565-1588.

Marcel, A.J. (2003). Introspective Report: Trust, Self Knowledge and Science. Journal of Consciousness Studies, 10 (9), 167-186.

Marcel, A.J. Phenomenal experience and functionalism. In Consciousness in Contemporary Science. A.J. Marcel and E. Bisiach (Eds), Oxford University Press, pp. 121-158, 1988.

Marcel, A.J. (1993). Slippage in the unity of consciousness. In Ciba Foundation Symposium No 174 - Experimental and Theoretical Studies of Consciousness. Chichester: John Wiley, pp. 168-186, 1993.

Marcel, A.J. The personal level in cognitive rehabilitation. In Neuropsychological Rehabilitation, N. von Steinbüchel, D.Y. von Cramon, E. Pöppel (Eds), Heidelberg: Springer-Verlag, pp. 155-168, 1992.

Marcel, A.J. The Sense of Agency: Awareness and Ownership of Actions and Intentions. In Roessler J. and Eilan N. (Eds) Agency and Self Awareness, Oxford University Press. 2003.

Marcel, A.J. & Lambie J.A. (2004). How many selves in emotion experience? Psychological Review, 111, 820-826.

Marcel, A.J., Tegnr, R & Nimmo-Smith, I., (2004). Anosognosia for plegia: specificity, extension, partiality, and disunity of bodily unawareness. Cortex, 40, 19-40.

Marcel, A., Postma, P., Gillmeister, H., Cox, S., Rorden, C., Nimmo-Smith, I., Mackintosh, B. (2004). Tactile Migration and Fusion in Healthy People: Premorbid Susceptibility to Allochiria, Neglect and Extinction? Neuropsychologia, 42, 1749-1767

Marcel, A.J., Mackintosh, B., Postma, P., Cusack, R., Vuckovich, J., Nimmo-Smith, I., and Cox, S.M.L. (2006). Is Susceptibility to Perceptual Migration and Fusion Modality-Specific or Multimodal? Neuropsychologia, 44, 693-710.

Marcel, A.J. & Dobel, C. (2005). Structured Perceptual Input Imposes an Egocentric Frame of Reference: Pointing, Imagery and Spatial Self-Consciousness. Perception, 34, 429-451.

Muggleton, N., Postma, P., Nimmo-Smith, I., Moutsopoulou, K., Marcel, A.J. and Walsh, V. (2006). TMS over right posterior parietal cortex induces neglect in a scene-based frame of reference. Neuropsychologia, 44,1222-1229.

Nimmo-Smith, I, Marcel, A.J., & Tegnr, R. (2005). A diagnostic test of unawareness of bilateral motor abilities in anosognosia for hemiplegia. Journal of Neurology, Neurosurgery and Psychiatry, 76, 1167-1169.