Slide 1

Slide 2 Perception and action what are the connections? Helge Malmgren Dept. of Philosophy, G teborg University KVIT, May 10, 2006 Slide 3 The seven basic ways is Perceiving is acting in order to We perceive in order to act What What we perceive is first and foremost action possibilities (affordances) leads directly Perception often leads directly to action implicit, procedural knowledge Perception often results in implicit, procedural knowledge perceive our own actions We more or less continually perceive our own actions (in a very special way) perceive other peoples actions We intermittently perceive other peoples actions (in a very special way) Slide 4 KVIT, May 10, 2006 Perceiving is acting See vs look (etcetera) Observation as result, but also as a process: move ourselves We move ourselves move and adjust our sensory organs We move and adjust our sensory organs use instruments We use instruments manipulate the object We manipulate the object (not only spatially) attend to selected objects and features We attend to selected objects and features Slide 5 KVIT, May 10, 2006 Attending and acting what are the connections? Active attention is under voluntary control When voluntary, it requires an effort Attention manifests itself in behaviour Attention is required for motor learning and automatization (Attending is learning!) Slide 6 KVIT, May 10, 2006 We perceive in order to act In order to identify the what/where of objects To continually monitor the results of our actions To steer our actions Evolutionary role... ...the reflex hierarchy... ... and conscious aims. (Blindsight) When the body is faster than the mind Slide 7 Steering and control of behaviour Ballisticpre-programmed Ballistic and pre-programmed movements: no feedback after Simple feedback control: error signal after the action Feedback afterwards is often too slow (you are already dead)... antecipatory feedback Knowledge about the systems dynamics enables estimation of the error in advance, and hence control through antecipatory feedback copy of the command With complete knowledge, external feedback becomes redundant. You may use a copy of the command instead. If you dont preprogramm... learned control All forward control mechanisms can in turn be controlled by feedback after the event learned control StartGoal StartGoal Start Goal Knowledge Result Check E( ) StartGoal Knowledge Check E( ) Result Start Goal Memory E( ) Slide 8 KVIT, May 10, 2006 Watching our own performance External External perception (including tactile) Internal proprioception Internal perception: proprioception (joints, muscles) (overrated?) corollary discharge efference copy No feedback but a copy of the command: corollary discharge, efference copy Fastlearnable Fast and learnable! Slide 9 KVIT, May 10, 2006 Uses (and abuses?) of the efference copy Correction of sensory signals affected by the movement (Helmholz) Forward control of the movement itself? Underlies our sense of agency? Constitutes most of the body schema (in adults)? Defective functioning in schizophrenia??? Slide 10 KVIT, May 10, 2006 Perceiving the actions of others Epistemology vs. psychology Theory of mind theories Simulation theories Bodily identification (mirror neurons, etc.) Another role for the efference copy: feeling the other s action in oneself? Imitation vs. joint action: cooperation & competition Slide 11 KVIT, May 10, 2006 Seeing movement even in still pictures Johansson s lights Seeing a movement as human depends only on its gross features (M. Schiffrer) Global features determine movement responses in the Rorschach test Rorschach also noted a latent imitation in this connection Two ways of perceiving movement: from the outside, and from the inside Physiognomic perception Slide 12 KVIT, May 10, 2006 Perceiving action possibilities To eat, or to be eaten, that is the question The reflex hierarchy Content vs form: embodied knowledge Practical perception Space perception involves the practical perceiving of possible movements timing Time perception involves practically perceiving the proper timing of actions Slide 13 KVIT, May 10, 2006 The arch-empiricist states......I believe whoever will look narrowly into his own thoughts, and examine what he means by saying he sees this or that thing at a distance, will agree with me, that what he sees only suggests to his understanding that, after having passed at a certain distance, to be measured by the motion of his body, which is perceivable by touch, he shall come to perceive such and such tangible ideas, which have been usually connected with such and such visible ideas. (Berkeley, G., An Essay towards a New Theory of Vision) Or, in the language of practical perception: Space is but a system of spatial affordances, organized through the body schema Slide 14 KVIT, May 10, 2006 Tidsliga gestalter och sensoriska buffertar Vi tycks i n gon mening samtidigt kunna uppfatta en tidslig utstr ckt process t.ex. en kort f ljd av toner Sperlings experiment (1960) tycktes visa att mer visuell information lagras n vad vi anv nder Den auditiva bufferten har l ngre utstr ckning (2 s?) Slide 15 KVIT, May 10, 2006 F rklaringsmodeller f r Sperlings resultat Ett rekurrent n tverk? Nej, det borde f rst ra mer av informationen Ett skiftregister? S rbart! Ett n tverk med tidsf nster och f rdr jda linjer! L ser Leibniz problem? Slide 16 KVIT, May 10, 2006 Time and the body schema Husserl s idea of time perception: impression, retention, and antecipation of next impression But: Our perception of time is to a large extent a practical perception of the proper timing of actions It is not only important to strike where the ball is, but also when it is there. (The when system?) Complete practical knowledge about the required timing entails an ability to pre-program the action And that is what perceptual learning is for... StartGoal Slide 17 KVIT, May 10, 2006 Overarching issues Most importantly: What are the philosophical implications of the connections between action and perception? Most importantly: inferential Are these connections incompatible with a view of perception as an inferential process? direct Do they entail that perception is, in any interesting sense, direct? mental representation Do they entail that perception does not involve mental representation? So, things may not be so simple after all...