Perceptual systems and perceiving

Perceptual systems have many functions. They determine which part of the sen-sory environment to attend to. They localise, recognize or determine where and what objects are. They abstract the critical information from objects and they keep the appearance of objects constant (Nolen-Hoeksema et. al, 2009). As Dennett (2002) describes, “when we perceive something in the environment we are not aware of every fleck of colour all at once, but rather of the highlights of the scene, an edited commentary on the things of interest” (Dennett, 2002, p. 136).

Perceiving involves processes similar to judgment and reasoning, but per-ceptual systems are more specialised and automatic (O’Callaghan, 2012; Laarni, Kalakoski & Saariluoma, 2001). Perceptual judgments are needed to combine a range of different cues in noise, ambiguity and from multiple sources of infor-mation into a sense-making perception (Mather, 2009). Different views exist about how much active modulation of the sensory information is needed before the perception emerges. The input from our sensory systems is usually dispersed and even conflicting, so some active information processing is required (Laarni et al., 2001). Perceptual processes can be seen as unconscious, undeliberate and subpersonal. They are specialised to particular types of tasks and information — processing information in the way of a representational system, as it transforms and constructs sensory information into rich perceptual representations of one's environment (O'Callaghan 2012; Laarni et al., 2001). The content of the perceptual experiences can also be false. One might think he saw something, even though that something does not actually exist. The perceptual experience seems as though something is seen, thus creating an illusory experience which too shares representational content (O'Callaghan 2012).

Describing the architecture of the perceptual systems can help explaining how these systems can complete their functions in the first place. There are at least three principles in the organisation of the perceptual systems. Firstly, the information processing happens in several different, hierarchically organised levels. The information presentation created on each level is based on the one created on the previous level. Secondly, perceptual systems are modular, so that

they are constituted of multiple, independent subsystems or modules. Those modules are specialised in different sensory characters such as orientation, move-ment or colour. Thirdly, a perceptual system has connections between function-ally specialised areas. The connections can be forward, backward or sideways, and can create different feedback loops. The connections between perceptual sys-tems and, e.g., memory can therefore help to explain, how the internal effectors can modulate the sensory information processing. (Laarni et al., 2001)

Schemas are used to explain how people in general are able to process the vast information of their perceptual world with human’s limited attentional ca-pacity. Somehow a person must focus the limited processing capabilities to the most critical tasks and leave the rest out of the conscious awareness, thus, auto-mating the mental processes as much as possible. In cognitive personality psy-chology, a schema represents the organisation of information. It influences how people perceive, remember and use that information. Content of schemas and how information is processed differ between individuals. (Pervin, 2003) Origi-nally proposed by Neisser (1976), a schema can be seen as a mental construct that is mediating perception, accepting some chunks of perceptual data and focusing attention to other aspects. Zimring and Gross (1991) see that once the selected schema is activated, it engages automated processes related to memory and ac-tions. According to Zimring and Gross (1991), “schemas seem to provide a con-struct that both responds to the setting and directs action in it and provide a pos-sible explanation for affective response to settings” (Zimring & Gross, 1991, p.

86). Schemas also explain why sometimes people remember something being present, like a table in an office room, even though in reality it was not. In such cases people rely on the schema of the office constructed from a memory.

Okimoto, Monreal and Bengler (2013) see that culture influences both a per-son’s cognition and perception: “Cultural practices encourage and sustain certain kinds of cognitive processes, which then perpetuate cultural practices” (Okimoto et al., 2013, p. 90). Perceiving and thought include temporal characters, future and past horizons of events, which merge the history and culture of a person into each conscious thought experienced at a specific moment in time. One’s later ex-periences can give new meaning to perceived objects creating new representa-tional wholes of beliefs and thoughts (Merleau-Ponty, 1996 / 2012).

Merleau-Ponty (1996 / 2012) sees that both the perception and the object of perception are paradoxical. We can think about the world only because we have some sort of preceding experience of it and being in it. Through perception we can try to reach something that exists. The object of perception is real for all those subjects who share the same situation, instead of being realistic for all intellectual consciousnesses. To be able to share the subjective experience of perception, one needs to be able to reflect oneself to other subjective beings and understand their behaviour, thoughts and speech. If one recognises the familiar behavioural char-acteristics that emerge in the shared events, one can confirm that these subjects share similar concepts of the phenomenal content of the world. It is thus creating an intersubjective, objective dimension for the objects of perception (Merleay-Ponty, 1996 / 2012).

Some contemporary models on perception consider perceiving not just as a subpersonal process. There the subject is seen as a dynamic and action-involved character, whose activity affects to the detection of the environment's features.

According to these models, perceiving is the way a person constructs the world and comes into contact with the environment in a skilful manner. This is a result of his or her own sensorimotor activity, mediated by the sensory responses from to one's actions and movements (O'Callaghan 2012). Noë (2004) has developed a theory of an enactive approach to perception, where he sees that perceiving has developed to enable action. The environment is reviewed as different possibili-ties to move and have sensorimotor contingency. He proposes that to perceive is

“to experience possibilities of movement and action afforded by the environment”

(Noë, 2004, p. 105). While interacting with one’s environment, a person gains un-derstanding of the concepts and effects of his movements, thus learning to apply the appropriate sensorimotor knowledge to different situations. This also leads to a task-specific perceptual adaptation. For example, affordances are different for different sized or shaped beings, and for beings with different levels and mas-tery of bodily and sensorimotor skills (Noë, 2004).

Ernst and Bülthoff (2004) have illustrated the affective interaction between actions and perception with an action-perception loop. Also according to their model, a person perceives in order to be able to act, and perception of the envi-ronment is altered by a person’s actions. The sensory information alone is not enough to create a full reconstruction of the environment. Thus, one often needs to use unconscious prior knowledge to interpret and estimate the often ambigu-ous sensory inputs. They suggest that the human mind integrates different sen-sory signals and by using Bayesian rules, which they call the estimate precision, the mind then weighs and chooses which signals from specific modalities might provide the most reliable information from the environment. This perception-action loop is shown in figure 3.

Dale, Tollefsen and Kello (2012) have reviewed studies about phenomenal consciousness in cognitive science and neuroscience. They propose to use a plu-ralistic approach in order to cover the complex and diverse mechanisms under-lying a phenomenal experience, which can vary on different spatial and temporal scales. They see that there are three key themes that identify aspects from the human nervous system as more abstract cognitive characterisations: the Global Workspace Theory, an action-centred consciousness and the role of social expe-rience and constitutivity. The Global Workspace Theory sees that there is inter-action between the mind’s different cognitive systems, which then produce ex-periences of individual events. The inputs can come from internal sources of the organism or from the external world, such as stimulus-specific predictions, which guide a person’s actions. Social dimensions have an important role encing humans’ interpersonal, cognitive processes. People act in and are influ-enced by a broader social and cultural context, which create different narrative structures, thus altering conscious experiences. These different interactions relate to different timescales, from a faster “phenomenological now” to a slower

mind-world coupling of events, such as social interactions and extended perceptual events.

FIGURE 3 The perception-action loop (Ernst & Bülthoff, 2004, p. 164).

The temporal scale of phenomenological experiences, the duration how long hu-mans can hold thoughts in mind, appears to be somewhat between seconds to minutes (Dale et al., 2012). The perception of time seems to be related to the action tendency. It is affected by a person’s attention and the amount of how much in-formation is being processed, because the difficulty of a task requires active cog-nitive processing. The complexity of the sensory stimulus relates to more passive-perceptual processing (Angrilli, Cherubini, Pavese & Manfredini, 1997). There are findings which indicate that also the movement of the stimulus alters the per-ception of time. More changes in the stimulus during an observed period of time are perceived as longer time intervals. Vice versa, time intervals where there are fewer changes in stimuli are perceived as lasting shorter amounts of time (Brown, 1995). Other factors that change time perception are the two components of emo-tions, a person’s level of arousal and the affective valence (Grondin, 2010; Angrilli et al., 1997). There seems to be a double mechanism for evaluating time that is triggered by different levels of arousal. High-arousal situations trigger an emo-tion driven, fast mechanism, and low arousal levels trigger an attenemo-tion-driven mechanism (Angrilli et al., 1997). Shorter or longer temporal periods than the length of a phenomenological experience, can exist only as abstractions of events.

There are slower timescales of learning, memory, social interactions, culture and evolution, that shape the dynamics between them and shorter temporal events.

Nevertheless, activities that happen in different timescales all have their impact on conscious experience. (Dale et al., 2012)