Co-speech gestureGesture is ubiquitous in communication; When people speak, they gesture.Co-speech gesture is evident across languages, cultures, and speakers of all ages.Blind speakers gesture to blind listeners.Speakers gesture when the listener isn’t present.Gesture assists in transmission of ideas from a speaker to a listenerProvides information to the listener about the speaker’s thoughReveals information that is often not found in speech; thus gesture supplements speechInterestingly, speakers and listeners tend to underreport gesture suggesting that its influence is often below awareness.Why do we gesture? Where do gestures come from?Insights from production.Growth Point Theory (McNeill, 1992)Gesture provides a different representation formatGesture conveys information that is visual, motor, spatialRepresentation to be communicated by an utteranceInformation Packaging Hypothesis (Kita, 2000)Gesture helps speakers organize and package visual spatial information so it is comparable to speech.Gestures, which are individual actions in space, help speakers to select and organize visual-spatial information that is appropriate for what is in speech.Describing the layout of furniture in the room.Using hands to represent a couch and chairHelps formulate utterance, The couch and chair are facing one another.Why do we gesture? Insights from production.Lexical Gesture Process Model (Krauss, 1998)Gesture primes lexical items, increasing their activation and making them easier to accessSpeaker makes rolling gesture, easier to retrieve roll, in “The ball rolled down the hill”When speakers told not to gesture, they become more dysfluent.Gesture as Simulated Action (Hostetter&Alibali, 2008)Speakers naturally activate simulations of actions and perceptual states when they produce speech.These simulations active motor and premotor cortex responsible for producing movements.If level of motor activation exceeds a pre-set threshold (determined by individual, social and contextual factors) then the speaker produces over motor movements (gestures).Summary so far....Gesture plays a role in language productionGesture communicates information not found in speech.Speech and gesture form an integrated systemGesturing may guide speech productionGesturing facilities lexical accessGestures aid in convening motor (and visual-spatial) informationWhy do we gesture? Insights from comprehension.Some debate about whether gesture aids in comprehension.But, some evidence that speakers intend for their gestures to be communicative.Speakers gesture more when gestures are visible.Gesture rate does NOT decline when speaking to different listeners.Some info is communicated uniquely in gesture and not speech.Some info communicated in gesture supplements info.Gesture in language learningGesture precedes speech and may play a role in linguistic development.Children begin to gesture between 8-12 months. Can point to object before producing first word.Children can combine speech and gesture.Pointing to bottle, says bottle. (Where, what).Gestures don’t just precede language development, they predict it!Can predict which lexical items enter vocabulary by looking at objects child indicted with gesture months earlier.Can predict onset of first two-word utterance (e.g., milk gone, cat run) by onset of gesture speech combination (e.g., point to bird + “nap”)Gesture in learning more broadlyFor a speaker, gesturing during encoding facilitates later recall Remember more items at test if you were gestureFor listener, seeing meaning gesture at encoding facilitates later recallGesturing at recall improves memory performanceGesture and learningGesture is important for acquiring new knowledgeTeachers’ gestures help students learn, especially when gesture and speech emphasize different informationStudents’ use of gesture helps them learnGestures often reflect emerging knowledge, before it can be put in speechGesture and learning; mismatchesChild explains how to solve math problem with some information in speech and some in gesture.7 + 4 + 2 = 7 + __Child explains how the numbers on the left side of the equation should be added to get the answer (incorrectly, 13)While gesturing about how the number on the right side should be subtracted from the total (correctly, 6)This speech-gesture mismatches reflects readiness to learn and is an index of knowledge transition.Gesture and cognitionThe gestures we produce reflect our prior experience.The gestures we see others produce affect our later actions.Cook &Tanenhaus, 2009Participants solved the Tower of Hanoi (TOH), then explained their solution.Gesture and cognitionThe gestures we produce reflect our prior experience.Cook &Tanenhaus, 2009Listeners solved the task on a computerPeople who saw curved gestures moved discs with higher trajectory than those who saw flatter gestures.Gesture ComprehensionGesture and cognitionThe gestures we produce reflect our prior experience.The gestures we see others produce affect our later actions.Participants mentally represented the gestures they saw, and these representations drove their future actions.Gesture and the brainImplications for understanding the instantiation of gesture in the brain, and as it relates to speech, but also for various types of disordered populations.For learning and for communicationMemoryDeclarative:Facts and eventsPatients with amnesiaProcedural:Skills, habits, abilitiesPatients with PDGesture Production - ResultsThose with intact procedural memory (healthy old and young participants, amnesic patients with impaired declarative memory)ti gesture produc2on reflects prior experienceThose with intact procedural memory (healthy old and young participants, amnesic patients with impaired declarative memory)ti later ac2ons were affected by the gestures they sawThese patterns were absent in the PD group with impaired procedural memoryCo-speech gestureGesture is ubiquitous in communication; When people speak, they gesture.Gesture influences language production and comprehensionGesture precedes and predicts language developmentGesture influences memory and learning and cognition more broadlyCSD 3117 1st Edition Lecture 24Outline of Last Lecture I. Language-as-productII. Language-as-actionIII. Types of Knowledge Underlying CommunicationIV. Speech Actsa. Direct vs Indirectb. Sources of Understandingc. The Cooperative PrincipleV. Conversation ManagementVI. Convergence in ConversationVII. Common