This study examined whether pupil size and response time would distinguish directed exploration from random exploration and exploitation. Eighty-nine participants performed the two-choice ...probabilistic learning task while their pupil size and response time were continuously recorded. Using LMM analysis, we estimated differences in the pupil size and response time between the advantageous and disadvantageous choices as a function of learning success, i.e., whether or not a participant has learned the probabilistic contingency between choices and their outcomes. We proposed that before a true value of each choice became known to a decision-maker, both advantageous and disadvantageous choices represented a random exploration of the two options with an equally uncertain outcome, whereas the same choices after learning manifested exploitation and direct exploration strategies, respectively. We found that disadvantageous choices were associated with increases both in response time and pupil size, but only after the participants had learned the choice-reward contingencies. For the pupil size, this effect was strongly amplified for those disadvantageous choices that immediately followed gains as compared to losses in the preceding choice. Pupil size modulations were evident during the behavioral choice rather than during the pretrial baseline. These findings suggest that occasional disadvantageous choices, which violate the acquired internal utility model, represent directed exploration. This exploratory strategy shifts choice priorities in favor of information seeking and its autonomic and behavioral concomitants are mainly driven by the conflict between the behavioral plan of the intended exploratory choice and its strong alternative, which has already proven to be more rewarding.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Currently, there are two opposing views on feature binding in the auditory modality: according to behavioral studies, this process requires focused attention, whereas electrophysiological studies ...suggest that feature binding may be fully automatic and independent of attention. Here, we examined whether feature binding depends on higher-level attentional processes by manipulating the attentional focus. We used four auditory stimuli that differed in two features: pitch and location. Two rare deviants could be detected within a sequence of two frequent standards exclusively by feature conjunctions rather than by any single feature alone. Event-related potentials to auditory stimuli were analyzed for four conditions: selective attention to target auditory deviants, selective ignoring of nontarget auditory deviants, nonselective distributed attention to all stimuli within auditory modality, and selective attention diverted from auditory to visual modality. The negative difference (Nd) between event-related potentials to deviants and standards was measured within two time intervals, corresponding to mismatch negativity (100-200 ms) and N2b (200-300 ms). Only under the condition of selective attention to specific feature conjunctions, prominent Nd was observed in mismatch negativity as well in N2b time ranges, whereas no significant Nd was observed in other conditions. As Nd is considered a marker of deviance processing, our results support the view that deviance was not detected unless attention was focused on the stimuli, thus supporting the view that feature binding requires attention.
Performance monitoring involves detection of action outcomes and initiation of appropriate behavioral adaptations. Psychophysiological mechanisms of performance monitoring remain largely understudied ...in the context of uncertainty that arises at the stage of stimulus identification and decision making, as well as in the context of inhibition/correction of the motor response. In the current study, we investigate relations between behavioral performance measures and several ERP components: N2, ERN/CRN and Pe. Participants performed a condensation task and made their responses by moving mouse cursor. Response registration using mouse tracking allowed us to obtain two independent behavioral measures: mouse movement initiation time and movement duration. Amplitude of N2 and CRN was dependent on movement initiation time: N2 was increased and CRN was decreased for ‘late’ correct responses compared with ‘early’ correct ones; this finding is compatible with the explanation that ‘late’ responses involve higher pre-response conflict and higher uncertainty compared with ‘early’ ones. Movement duration time was a novel independent behavioral parameter, that cannot be measured using traditional keystrokes. This behavioral measure was related to the early Pe: its amplitude was more positive for ‘long’ responses compared with ‘short’ ones. This finding may be explained by mechanisms of an ongoing response inhibition. We suggest that this effect is linked to response stopping, which may be related to outcome awareness.
Мониторинг выполнения включает оценку результатов собственного поведения и инициацию его адаптивных перестроек. Психофизиологические механизмы мониторинга выполнения остаются малоизученными в контексте неопределенности, возникающей на этапе распознавания сенсорной информации и принятия решения, а также в контексте торможения/коррекции двигательного ответа. В данном исследовании мы изучали связь между поведенческими показателями выполнения задачи и компонентами потенциалов, связанных с событиями: N2, ERN/CRN и Pe. Испытуемые выполняли конденсационную задачу и давали ответы путем перемещения компьютерной мыши. Такой способ записи ответов позволил получить два независимых поведенческих показателя: время начала движения компьютерной мыши и его продолжительность. Время начала движения можно рассматривать как эквивалент стандартного времени реакции. Амплитуда компонентов N2 и CRN зависела от времени начала движения: амплитуда N2 была увеличена, а амплитуда CRN снижена для «поздних» (задержанных) правильных ответов по сравнению с «ранними» (более быстрыми по времени начала движения мыши). Предположительно, «поздние» ответы характеризуются более сильным конфликтом между альтернативами, более высоким уровнем неопределенности по сравнению с «ранними». Продолжительность движения курсора мыши представляет собой новый поведенческий показатель, измерение которого традиционными методами представляется затруднительным. Амплитуда сигнала во временно́м окне раннего Pe была связана с продолжительностью движения и являлась более высокой в случае «длительных» ответов по сравнению с «короткими». Такого рода взаимосвязь можно объяснить работой механизмов торможения выполняемого ответа, которое, в свою очередь, может запускаться в связи с осознанием потенциальной вероятности совершения ошибки.
PDF