Presentations

Abstract

When processing visual objects, we integrate visual, linguistic and spatial information to form an episodic trace. Re-activating one aspect of the episodic trace of an object re-activates the entire bundle making all integrated information available. Using the blank screen paradigm [1], researchers observed that upon processing spoken linguistic input, participants tended to make eye movements on a blank screen, fixating locations that were previously occupied by objects mentioned in the linguistic utterance or were related. Ferreira and colleagues [2] suggested that 'looking at nothing' facilitated memory retrieval. However, this claim lacks convincing empirical support. In Experiment 1, Dutch participants looked at four-object-displays. Three objects were related to a spoken target word. Given the target word 'beker' (beaker), the display featured a phonological (a bear), a shape (a bobbin), a semantic (a fork) competitor, and an unrelated distractor (an umbrella). Participants were asked to name the objects as fast as possible. Subsequently, the objects disappeared. Participants fixated the center of the screen and listened to the target word. They had to carry out a semantic judgment task (indicating in which position an object had appeared that was semantically related to the objects) or a visual shape similarity judgment (indicating the position of the object similar in shape to the target). In both conditions, we observed that participants re-fixated the empty target location before responding. The set-up of Experiment 2 was identical except that we asked participants to maintain fixating the center of the screen while listening to the spoken word and responding. Performance accuracy was significantly lower in Experiment 2 than in Experiment 1. The results indicate that memory retrieval for objects is impaired when participants are not allowed to look at relevant, though empty locations. [1] Altmann, G. (2004). Language-mediated eye movements in the absence of a visual world: the 'blank screen paradigm'. Cognition, 93(2), B79-B87. [2] Ferreira, F., Apel, J., & Henderson, J. M. (2008). Taking a new look at looking at nothing. Trends Cogn Sci, 12(11), 405-410.

Abstract

Sentence formulation requires mapping pre-verbal messages onto linguistic structures. This message-to-language
mapping is often evaluated in eye-tracking tasks where speakers describe pictured events (The dog chased the mailman).
Speakers can begin sentence formulation by quickly selecting the first-fixated character as the sentential starting point
(lexical incrementality), or generating a rudimentary sentence plan based on their construal of the event gist before
selecting a starting point (hierarchical incrementality; Kuchinsky & Bock, 2010). Lexical incrementality predicts fast
divergence of fixations while hierarchical incrementality predicts slower divergence of fixations to the two characters
within 200ms of picture onset.

Abstract

Much evidence demonstrates cerebellar involvement in language [1] but a theoretical framework about its precise role is lacking. In cerebellar motor control an influential model ascribes the cerebellum a predictive role [2]. It has been argued that cerebellar nonmotor regions perform similar computations as motor regions, and both are involved in online prediction [2]. We test this hypothesis by administering repetitive transcranial magnetic stimulation (rTMS) to the right cerebellum, a region implicated in language [3] during a predictive language task. Methods Visual World task [4]: Participants' eye movements were recorded while they listened to sentences and looked at a computer display of an agent and 4 objects, one of which (the target) was mentioned in the sentence. In the Prediction condition the object could be predicted on the basis of the verb; on Control trials it could not. We hypothesised that rTMS to the right cerebellum should make target fixation slower in the Prediction condition, but not in the Control condition. TMS protocol: TMS was delivered between two task blocks. In the cerebellar rTMS group (n = 22) the stimulation site was 1cm down and 3cm right of the inion. Participants received 10min of 1Hz rTMS. In addition, we tested two control groups. In the vertex rTMS group (n = 21), rTMS was applied at the same intensity, duration and frequency as in the cerebellar rTMS group, but over the vertex. In the no stimulation group (n = 22) the coil was placed over the cerebellar stimulation site but no pulses were delivered. Results As hypothesised, participants in the cerebellar rTMS group took longer to fixate the target after TMS in the Prediction condition but not in the Control condition (Block-by-Condition interaction: F(1,21) = 8.848, p = 0.007). This interaction was not found in either the vertex rTMS group (F(1,20) = 0.064, p = 0.802) or the no stimulation group (F(1,21) = 2.461, p = 0.132). Conclusions Here, we show that rTMS to the right cerebellum selectively affects linguistic prediction. These results provide additional evidence that the cerebellum plays a role in language and support theoretical accounts that the cerebellum contributes to nonmotor functions, as it does to motor functions, by online prediction. 1. Strick et al (2009). Cerebellum and nonmotor function. Annu Rev Neurosci, 32, 413-134 2. Miall et al (1993). Is the cerebellum a Smith predictor. J Mot Behav, 25, 203-216 3. Marien et al (2001). The lateralised linguistic cerebellum: a review and a new hypothesis. Brain and Language, 79, 580-600 4. Altmann & Kamide (1999). Incremental interpretation at verbs. Cognition, 73, 247-264

Abstract

In sentence comprehension, readers and listeners often anticipate upcoming information (e.g., Altmann & Kamide, 1999). We investigated two aspects of this process, namely 1) what is pre-activated when anticipating an upcoming word (the contents of predictions), and 2) which cognitive mechanisms are involved. The contents of predictions at the level of meaning could be restricted to functional semantic attributes (e.g., edibility; Altmann & Kamide, 1999). However, when words are processed other types of information can also be activated, such as object shape representations. It is unknown whether this type of information is already activated when upcoming words are predicted. Forty-five adult participants listened to predictable words in sentence contexts (e.g., "In 1969 Neil Armstrong was the first man to set foot on the moon.") while looking at visual displays of four objects. Their eye movements were recorded. There were three conditions: target present (e.g., a moon and three distractor objects that were unrelated to the predictable word in terms of semantics, shape, and phonology), shape competitor (e.g., a tomato and three unrelated distractors), and distractors only (e.g., rice and three other unrelated objects). Across lists, the same pictures and sentences were used in the different conditions. We found that participants already showed a significant bias for the target object (moon) over unrelated distractors several seconds before the target was mentioned, demonstrating that they were predicting. Importantly, there was also a smaller but significant shape competitor (tomato) preference starting at about a second before critical word onset, consistent with predictions involving the referent’s shape. The mechanisms of predictions could be specific to language tasks, or language could use processing principles that are also used in other domains of cognition. We investigated whether performance in non-linguistic prediction is related to prediction in language processing, taking an individual differences approach. In addition to the language processing task, the participants performed a simple cueing task (after Posner, Nissen, & Ogden, 1978). They pressed one of two buttons (left/right) to indicate the location of an X symbol on the screen. On half of the trials, the X was preceded by a neutral cue (+). On the other half, an arrow cue pointing left (<) or right (>) indicated the upcoming X's location with 80% validity (i.e., the arrow cue was correct 80% of the time). The SOA between cue and target was 500 ms. Prediction was quantified as the mean response latency difference between the neutral and valid condition. This measure correlated positively with individual participants' anticipatory target and shape competitor preference (r = .27; r = .45), and was a significant predictor of anticipatory looks in linear mixed-effects regression models of the data. Participants who showed more facilitation from the arrow cues predicted to a higher degree in the linguistic task. This suggests that prediction in language processing may use mechanisms that are also used in other domains of cognition. References Altmann, G. T. M., & Kamide, Y. (1999). Incremental interpretation at verbs: Restricting the domain of subsequent reference. Cognition, 73(3), 247-264. Posner, M. I., Nissen, M. J., & Ogden, W. C. (1978). Attended and unattended processing modes: The role of set for spatial location. In: H.L. Pick, & I.J. Saltzman (Eds.), Modes of perceiving and processing information. Hillsdale, N.J.: Lawrence Erlbaum Associates.