Verb Comprehension Deficits in Probable Alzheimer's Disease

Studies of lexical comprehension in probable Alzheimer's disease (pAD) have focused almost exclusively on nouns. In the following preliminary study, we examined whether lexical comprehension for verbs is also impaired in 25 pAD patients. The semantic meaning of motion verbs, cognition verbs, and perception verbs was assessed with a triadic comparison task. Structural meaning associated with these verbs was evaluated by asking the patients to judge the coherence of sentence frames that accept these verbs naturally or awkwardly. We found that pAD patients are significantly impaired at identifying semantic relations among verbs. pAD patients also encountered significantly more difficulty judging the coherence of sentences than control subjects. Correlation and regression analyses demonstrated that semantic characteristics of verbs are projected from the verbs' sentence frames in control subjects, but there was minimal evidence for such a structural–semantic relationship in pAD. We consider several possible explanations for our preliminary observations of an impairment that has consequences for processing both semantic and structural aspects of verb meaning.     

Understanding the abstract role of speech in communication at 12 months

Adult humans recognize that even unfamiliar speech can communicate information between third parties, demonstrating an ability to separate communicative function from linguistic content. We examined whether 12-month-old infants understand that speech can communicate before they understand the meanings of specific words. Specifically, we test the understanding that speech permits the transfer of information about a Communicator's target object to a Recipient. Initially, the Communicator selectively grasped one of two objects. In test, the Communicator could no longer reach the objects. She then turned to the Recipient and produced speech (a nonsense word) or non-speech (coughing). Infants looked longer when the Recipient selected the non-target than the target object when the Communicator had produced speech but not coughing (Experiment 1). Looking time patterns differed from the speech condition when the Recipient rather than the Communicator produced the speech (Experiment 2), and when the Communicator produced a positive emotional vocalization (Experiment 3), but did not differ when the Recipient had previously received information about the target by watching the Communicator's selective grasping (Experiment 4). Thus infants understand the information-transferring properties of speech and recognize some of the conditions under which others' information states can be updated. These results suggest that infants possess an abstract understanding of the communicative function of speech, providing an important potential mechanism for language and knowledge acquisition.     

Can an agent's false belief be corrected by an appropriate communication? Psychological reasoning in 18-month-old infants

Do 18-month-olds understand that an agent's false belief can be corrected by an appropriate, though not an inappropriate, communication? In Experiment 1, infants watched a series of events involving two agents, a ball, and two containers: a box and a cup. To start, agent1 played with the ball and then hid it in the box, while agent2 looked on. Next, in agent1's absence, agent2 moved the ball from the box to the cup. When agent1 returned, agent2 told her "The ball is in the cup!" (informative-intervention condition) or "I like the cup!" (uninformative-intervention condition). During test, agent1 reached for either the box (box event) or the cup (cup event). In the informative-intervention condition, infants who saw the box event looked reliably longer than those who saw the cup event; in the uninformative-intervention condition, the reverse pattern was found. These results suggest that infants expected agent1's false belief about the ball's location to be corrected when she was told "The ball is in the cup!", but not "I like the cup!". In Experiment 2, agent2 simply pointed to the ball's new location, and infants again expected agent1's false belief to be corrected. These and control results provide additional evidence that infants in the second year of life can attribute false beliefs to agents. In addition, the results suggest that by 18 months of age infants expect agents' false beliefs to be corrected by relevant communications involving words or gestures.     

15-month-old infants detect violations in pretend scenarios

Are 15-month-old infants able to detect a violation in the consistency of an event sequence that involves pretense? In Experiment 1, infants detected a violation when an actor pretended to pour liquid into one cup and then pretended to drink from another cup. In Experiment 2, infants no longer detected a violation when the cups were replaced with objects not typically used in the context of drinking actions, either shoes or tubes. Experiment 3 showed that infants' difficulty in Experiment 2 was not due to the use of atypical objects per se, but arose from the novelty of seeing an actor appearing to drink from these objects. After receiving a single familiarization trial in which they observed the actor pretend to drink from either a shoe or a tube, infants now detected a violation when the actor pretended to pour into and to drink from different shoes or tubes. Thus, at an age (or just before the age) when infants are beginning to engage in pretend play, they are able to show comprehension of at least one aspect of pretense in a violation-of-expectation task: specifically, they are able to detect violations in the consistency of pretend action sequences.     

A comparison of chinchilla auditory evoked response and behavioral response thresholds

The auditory sensitivity of the chinchilla was measured by both a behavioral and auditory evoked-response (AER) procedure. There was no significant difference in either the waveform or the threshold of the AER recorded over the tentorium from awake and anesthetized chinchillas. The chinchilla threshold for pure tones appears to be more sensitive when measured by the behavioral technique than by the AER method. Both the AER and behavioral response of three chinchillas exposed to a 105 dB SPL octave band of noise centered at 2 KHz for 3 h shifted markedly after the exposure. However, the difference between the AER and behavioral response threshold was reduced or absent. During the process of recovery the difference between the two responses begins to reappear.     

Infants learn phonotactic regularities from brief auditory experience

Two experiments investigated whether novel phonotactic regularities, not present in English, could be acquired by 16.5-month-old infants from brief auditory experience. Subjects listened to consonant-vowel-consonant syllables in which particular consonants were artificially restricted to either initial or final position (e.g. /baep/ not /paeb/). In a later head-turn preference test, infants listened longer to new syllables that violated the experimental phonotactic constraints than to new syllables that honored them. Thus, infants rapidly learned phonotactic regularities from brief auditory experience and extended them to unstudied syllables, documenting the sensitivity of the infant's language processing system to abstractions over linguistic experience.     

Learning phonotactic constraints from brief auditory experience

Three experiments asked whether phonotactic regularities not present in English could be acquired by adult English speakers from brief listening experience. Subjects listened to consonant-vowel-consonant (CVC) syllables displaying restrictions on consonant position. Responses in a later speeded repetition task revealed rapid learning of (a) first-order regularities in which consonants were restricted to particular positions (e.g. [baep] not *[paeb]), and (b) second-order regularities in which consonant position depended on the adjacent vowel (e.g. [baep] or [pIb], not *[paeb] or *[bIp]). No evidence of learning was found for second-order regularities in which consonant position depended on speaker's voice. These results demonstrated that phonotactic constraints are rapidly learned from listening experience and that some types of contingencies (consonant-vowel) are more easily learned than others (consonant-voice).     

Persistent structural priming from language comprehension to language production

To examine the relationship between syntactic processes in language comprehension and language production, we compared structural persistence from sentence primes that speakers heard to persistence from primes that speakers produced. [Bock, J. K., & Griffin, Z. M. (2000). The persistence of structural priming: transient activation or implicit learning? Journal of Experimental Psychology: General, 129, 177-192.] showed that the production of target priming structures increased the probability of spontaneously using the same structures to describe events in subsequent pictures that were semantically unrelated to the primes. These priming effects persisted across as many as ten intervening filler trials. The present studies replicated these results using auditorily presented primes to which participants only listened. The results indicated persistence of priming across all lags, with relative magnitudes of priming as large as those observed by Bock and Griffin. The implication is that structural priming is persistent regardless of the modality in which language structures are experienced, underscoring the power of priming as an implicit learning mechanism.