Say it with flowers! An fMRI study of object mediated communication

Human communicational interaction can be mediated by a host of expressive means from words in a natural language to gestures and material symbols. Given the proper contextual setting even an everyday object can gain a mediating function in a communicational situation. In this study we used event-related fMRI to study the brain activity caused by everyday material objects when they are perceived as signals. We found that comprehension of material signals activates bilaterally areas of the ventral stream and pars triangularis of the inferior frontal cortex, that is, areas traditionally associated with verbal language and semantics. In addition, we found that right-hemisphere inferior frontal cortex is recruited as a function of the increasing unconventionality of communicative objects. Together these findings support an interpretation of the traditional language areas as playing a more general role across modalities in relation to communicational mediation of social semantic meaning.     

Infant sensitivity to distributional information can affect phonetic discrimination.

For nearly two decades it has been known that infants' perception of speech sounds is affected by native language input during the first year of life. However, definitive evidence of a mechanism to explain these developmental changes in speech perception has remained elusive. The present study provides the first evidence for such a mechanism, showing that the statistical distribution of phonetic variation in the speech signal influences whether 6- and 8-month-old infants discriminate a pair of speech sounds. We familiarized infants with speech sounds from a phonetic continuum, exhibiting either a bimodal or unimodal frequency distribution. During the test phase, only infants in the bimodal condition discriminated tokens from the endpoints of the continuum. These results demonstrate that infants are sensitive to the statistical distribution of speech sounds in the input language, and that this sensitivity influences speech perception.     

Is Internalism About Knowledge Consistent with Content Externalism?

There is widespread suspicion that there is a principled conflict between epistemic internalism and content externalism (or anti-individualism). Despite the prominence of this suspicion, it has rarely been substantiated by explicit arguments. However, Duncan Pritchard and Jesper Kallestrup have recently provided a prima facie argument concluding that internalism about knowledge and externalism about content are incompatible. I criticize the incompatibilist argument and conclude that the purported incompatibility is, at best, prima facie. This is, in part, because several steps in the argument are faulty and, in part, because there are promising responses available to the compatibilists.

Testing an App-Assisted Treatment for Suicide Prevention in a Randomized Controlled Trial: Effects on Suicide Risk and Depression

Suicide is a global public health problem and effective psychological interventions are needed. The objective of the present study was to evaluate the effect of an app-assisted suicide prevention treatment on suicide risk and depression. One hundred twenty-nine participants were randomized to treatment as usual (TAU), consisting of psychotherapy adhering to the framework of Collaborative Assessment and Management of Suicidality (CAMS), with (TAU + APP, N = 60) or without (TAU, N = 69) access to a mobile application (i.e., LifeApp’tite). Suicide risk and symptoms of depression were assessed pre- and posttherapy, and at 4-month follow-up. The TAU + APP group showed a smaller decrease on self-reported suicide risk at the end of treatment, corresponding to a medium between-group effect size (p = .008, d = 0.46). At the 4-month follow-up this was the case only at the trend level, where the effect size was also of a smaller magnitude (p = .057, d = 0.30). No differences between the treatment groups were observed on self-reported depressive symptoms, either immediately following treatment (p = .732, d = 0.05) or at follow-up (p = .467, d = 0.11). The unexpected negative effect concerning suicide risk points to crucial consideration of issues pertaining to timing, dosing, and content when adding new technology to existing treatments both in this and other populations.     

The role of prior experience in language acquisition

Learners exposed to an artificial language recognize its abstract structural regularities when instantiated in a novel vocabulary (e.g., Gómez, Gerken, & Schvaneveldt, 2000; Tunney & Altmann, 2001). We asked whether such sensitivity accelerates subsequent learning, and enables acquisition of more complex structure. In Experiment 1, pre-exposure to a category-induction language of the form aX bY sped subsequent learning when the language is instantiated in a different vocabulary. In Experiment 2, while naíve learners did not acquire an acX bcY language, in which aX and bY co-occurrence regularities were separated by a c-element, prior experience with an aX bY language provided some benefit. In Experiment 3 we replicated this finding with a 24-hour delay between learning phases, and controlled for prior experience with the aX bY language's prosodic and phonological characteristics. These findings suggest that learners, and the structure they can acquire, change as a function of experience.     

Eye movement suppression interferes with construction of object-centered spatial reference frames in working memory

The brain’s frontal eye fields (FEF), responsible for eye movement control, are known to be involved in spatial working memory (WM).In a previous fMRI experiment (Wallentin, Roepstorff & Burgess, Neuropsychologia, 2008) it was found that FEF activation was primarily related to the formation of an object-centered, rather than egocentric, spatial reference frame. In this behavioral experiment we wanted to demonstrate a causal relationship between eye movement control and manipulation of spatial reference frames. Sixty-two participants recalled either spatial (“Was X in front of Y?”) or non-spatial (“Was X darker than Y?”) relations in a previously shown image containing two to four objects, each with an intrinsic orientation and unique luminance. During half of all recall trials a moving visual stimulus was presented, which participants had to ignore, thus suppressing eye movement. Response times were significantly slower for spatial relations with distraction while there was no effect on non-spatial relations. There was no effect on accuracy, i.e. WM maintenance. This is consistent with the hypothesis that in spatial representations the FEFs are involved in WM content manipulation, such as establishing an object-centered spatial frame of reference.     

BOLD response to motion verbs in left posterior middle temporal gyrus during story comprehension

A primary focus within neuroimaging research on language comprehension is on the distribution of semantic knowledge in the brain. Studies have shown that the left posterior middle temporal gyrus (LPMT), a region just anterior to area MT/V5, is important for the processing of complex action knowledge. It has also been found that motion verbs cause activation in LPMT. In this experiment we investigated whether this effect could be replicated in a setting resembling real life language comprehension, i.e. without any overt behavioral task during passive listening to a story. During fMRI participants listened to a recording of the story “The Ugly Duckling”. We incorporated a nuisance elimination regression approach for factoring out known nuisance variables both in terms of physiological noise, sound intensity, linguistic variables and emotional content. Compared to the remaining text, clauses containing motion verbs were accompanied by a robust activation of LPMT with no other significant effects, consistent with the hypothesis that this brain region is important for processing motion knowledge, even during naturalistic language comprehension conditions.     

Discursive justification and skepticism

In this paper, I consider how a general epistemic norm of action that I have proposed in earlier work should be specified in order to govern certain types of acts: assertive speech acts. More specifically, I argue that the epistemic norm of assertion is structurally similar to the epistemic norm of action. First, I argue that the notion of warrant operative in the epistemic norm of a central type of assertion is an internalist one that I call ??discursive justification.?? This type of warrant is internalist insofar as it requires that the agent is capable of articulating reasons for her belief. The idea, roughly, is that when one asserts that p, one is supposed to be in a position to give reasons for believing that p. Bonjour??s reliable clairvoyant Norman, for example, is not in an epistemic position to make assertions regarding the president??s whereabouts??even if Norman knows the president??s whereabouts. In conclusion, I briefly consider whether a type of skeptical argument??often labeled Agrippa??s Trilemma??is motivated, at least in part, by the fact that responses to it violate the relevant epistemic norm of assertion.