Economic approaches to decision making assume that people attach values to prospective goods and act in order to maximise their obtained value. Neuroeconomics strives to observe these values directly in the brain. A widely used valuation term in formal learning and decision-making models is the reward prediction error: the value of an outcome relative to its expected value. An influential theory (Holroyd and Coles, 2002) claims that an electrophysiological component, the feedback related negativity (FRN), codes a reward prediction error in the human brain. Such a component should be sensitive to both the prior likelihood of reward and its magnitude on receipt. A number of studies have found the FRN to be insensitive to reward magnitude, thus questioning the Holroyd and Coles account.However, because of marked inconsistencies in how the FRN is measured, a meaningful synthesis of this evidence is highly problematic. We conducted a meta-analysis of the FRN's response to both reward magnitude and likelihood using a novel method in which published effect sizes were disregarded in favour of direct measurement of the published waveforms themselves, with these waveforms then averaged to produce "great-grand averages". Under this standardised measure, the meta-analysis revealed strong effects of magnitude and likelihood on the FRN consistent with it encoding a reward prediction error. In addition, it revealed strong main effects of reward magnitude and likelihood across much of the waveform, indicating sensitivity to unsigned prediction errors or "salience". The great grand average technique is proposed as a general method for meta-analysis of ERPs.Keywords: Feedback related negativity (FRN); Event-related potential (ERP); Reward prediction error (RPE); Unsigned prediction error; Meta-analysis; Great grand average Masked Manuscript without Author Information 2 Explaining human behavior under choice requires understanding how humans assign value to goods and actions. This valuation occurs at a nexus of psychological influences running from high level processes such as framing effects and counterfactual comparisons down to basic physiological influences such as satiation. It is likely to be dependent on an individual's knowledge both through conscious extrapolation from experience and simple reinforcement learning.Early attempts to explain human valuation were aimed at demonstrating that choice was entirely rational, and embodied key axioms of neoclassical economics such as expected utility. This approach employed a black box methodology, observing the "revealed preferences" of outward behavior in favor of the underlying apparatus of valuation, and treating humans only "as if" they computed utilities (Friedman, 1953;Samuelson, 1937).These assumptions have come under attack from the field of behavioral economics, which has succeeded in documenting widespread and consistent deviations from rational choice. A fully psychological approach, behavioral economics has endeavored to open the black box and consider a more va...
The processing costs involved in regional accent normalization were evaluated by measuring differences in lexical decision latencies for targets placed at the end of sentences with different French regional accents. Over a series of 6 experiments, the authors examined the time course of comprehension disruption by manipulating the duration and presentation conditions of accented speech. Taken together, the findings of these experiments indicate that regional accent normalization involves a short-term adjustment mechanism that develops as a certain amount of accented signal is available, resulting in a temporary perturbation in speech processing.
This study examines children's ability to detect accent-related information in connected speech. British English children aged 5 and 7 years old were asked to discriminate between their home accent from an Irish accent or a French accent in a sentence categorization task. Using a preliminary accent rating task with adult listeners, it was first verified that the level of accentedness was similar across the two unfamiliar accents. Results showed that whereas the younger children group behaved just above chance level in this task, the 7-year-old group could reliably distinguish between these variations of their own language, but were significantly better at detecting the foreign accent than the regional accent. These results extend and replicate a previous study (Girard, Floccia, & Goslin, 2008) in which it was found that 5-year-old French children could detect a foreign accent better than a regional accent. The factors underlying the relative lack of awareness for a regional accent as opposed to a foreign accent in childhood are discussed, especially the amount of exposure, the learnability of both types of accents, and a possible difference in the amount of vowels versus consonants variability, for which acoustic measures of vowel formants and plosives voice onset time are provided.
This study used event-related potentials (ERPs) to examine whether we employ the same normalisation mechanisms when processing words spoken with a regional accent or foreign accent. Our results showed that the Phonological Mapping Negativity (PMN) following the onset of the final word of sentences spoken with an unfamiliar regional accent was greater than for those produced in the listener's own accent, whilst PMN for foreign accented speech was reduced. Foreign accents also resulted in a reduction in N400 amplitude when compared to both unfamiliar regional accents and the listener's own accent, with no significant difference found between the N400 of the regional and home accents. These results suggest that regional accent related variations are normalised at the earliest stages of spoken word recognition, requiring less top-down lexical intervention than foreign accents.
Recent data suggest that the first presentation of a foreign accent triggers a delay in word identification, followed by a subsequent adaptation. This study examines under what conditions the delay resumes to baseline level. The delay will be experimentally induced by the presentation of sentences spoken to listeners in a foreign or a regional accent as part of a lexical decision task for words placed at the end of sentences. Using a blocked design of accents presentation, Experiment 1 shows that accent changes cause a temporary perturbation in reaction times, followed by a smaller but long-lasting delay. Experiment 2 shows that the initial perturbation is dependent on participants' expectations about the task. Experiment 3 confirms that the subsequent long-lasting delay in word identification does not habituate after repeated exposure to the same accent. Results suggest that comprehensibility of accented speech, as measured by reaction times, does not benefit from accent exposure, contrary to intelligibility.
This study examines children's metaphonological awareness for accent-related information in connected speech. In the first experiment, 5-to 6-year-old Frenchspeaking children were asked to discriminate between Southern and Northern accented French in a sentence categorization task. It was found that these children were not able to reliably distinguish between these native variations of their own language, but were able to distinguish between their own accent and a strong foreign accent in Experiment 2. These findings were also replicated using a speaker discrimination task in Experiment 3, where children were asked to detect pairs of speakers sharing the same accent amongst speaker pairs with different accents. Whilst these experiments have shown that 5-to 6-year-old children do not use non-familiar regional accents as a discriminatory cue, they are able to perceive the differences between accents, as demonstrated in the AX task used in Experiment 4. The factors underlying the relative lack of awareness for a regional accent as opposed to a foreign accent in childhood are discussed, especially regarding the amount of exposure and the learnability of both types of accents.
A wealth of behavioral data has shown that the visual properties of objects automatically potentiate motor actions linked with them, but how deeply are these affordances embedded in visual processing? In the study reported here, we used electrophysiological measures to examine the time course of affordance resulting from the leftward or rightward orientation of the handles of common objects. Participants were asked to categorize those objects using a left- or right-handed motor response. Lateralized readiness potentials showed rapid motor preparation in the hand congruent with the affordance provided by the object only 100 to 200 ms after stimulus presentation and up to 400 ms before the actual response. Examination of event-related potentials also revealed an effect of handle orientation and response-hand congruency on the visual P1 and N1 components. Both of these results suggest that activity in the early sensory pathways is modulated by the action associations of objects and the intentions of the viewer.
Models of reinforcement learning represent reward and punishment in terms of reward prediction errors (RPEs), quantitative signed terms describing the degree to which outcomes are better than expected (positive RPEs) or worse (negative RPEs). An electrophysiological component known as feedback related negativity (FRN) occurs at frontocentral sites 240-340 ms after feedback on whether a reward or punishment is obtained, and has been claimed to neurally encode an RPE. An outstanding question however, is whether the FRN is sensitive to the size of both positive RPEs and negative RPEs. Previous attempts to answer this question have examined the simple effects of RPE size for positive RPEs and negative RPEs separately. However, this methodology can be compromised by overlap from components coding for unsigned prediction error size, or "salience", which are sensitive to the absolute size of a prediction error but not its valence. In our study, positive and negative RPEs were parametrically modulated using both reward likelihood and magnitude, with principal components analysis used to separate out overlying components. This revealed a single RPE encoding component responsive to the size of positive RPEs, peaking at ~330 ms, and occupying the delta frequency band. Other components responsive to unsigned prediction error size were shown, but no component sensitive to negative RPE size was found.
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