The Cognitive And Neural Mechanism Of Transitive Inference

Transitive reasoning/transitive inference (TI) is a kind of inference consisting of two or more judgments which have transitive relations. It belongs to indirect inference, which requires to deduce and integrate the relations of premise items presented asynchronously from premise relations. It is a special type of deductive inference. Both of animals and humans could display TI. The act of TI is an inherent ability of humans to adapt to the external environment, and lies in everywhere and everytime in our lives. Meanwhile, TI is a key competence of cognition development. It is a primary way to explain inference, even thinking. TI playes an important role in children's cognition development. Flavell had predicted that "the substance and development of individual transitive relation inference will continue to be a project vigorous and full of controversies". The cognitive and neural mechanism research of TI is of great scientific and applied value. It is a hot spot and main focus of cognitive psychology, psychology of thinking, cognitive neural science and other subjects so far. Behavioral, fMRI, PET, ERP, eye tracking and brain injury reports and reviews on TI have been published in the global authoritative academic magazines—Science, Nature, Nature Neuroscience, Neuron, PNAS, Trends in Cognitive Science and Psychological Review. Therefore, combining the traditional behavioral research tools with modern research tools such as ERP extensively to study the cognitive and neural mechanism of TI systematically is of great values. Its scientific value lies in revealing not only the neural processes of TI, but also the way for the mysterious brain to process advanced thinking. So the applied value of TI study is obvious.There are usually three types of transitivive inference situations in real life: First of all, real TI situation. Here the transition\transitivity is affirmatory. Individuals make affirmatory transitive inference conclusions in accordance with transitive relation. Second, social TI situation. The transition is uncertain in this context. Whether the relations are in transition depends on the actual situation and social experience. Third, negative TI. Based on premise relations, the inevitable conclusion of non-transition can be made. These three types of inference differ in transitive levels, the highest transition appears in real TI, social TI second, negative TI the lowest. Obviously, people are facing more uncertain transitive inference situations in real life. However, these widespread uncertain TI received rare attentions. When confronting with a TI event in an uncertain situation (for example, A is one of schoolmates of B, B is one of schoolmates of C, is A one of schoolmates of C?), individuals need to do transitive inference according to actual situation and related social experience and knowledge. This study mainly focus on the cognitive processes and neural mechanisms of the traditional TI (real TI), TI in uncertain situation (social TI), as well as negative TI (also called non-transitive inference). Thus, the study developed and increased a new research task—"Good Friends" task combining with the traditional task, and carried out behavioral researches and ERP experimental studies to explore specifically the inference processes, strategies-applying, influential factors and neural mechanismsof real, social, and negative TI. This study consists of four parts(experiments). The first part is mainly about experiment 1. Subjects were chosen from undergraduate students, and the materials were real TI tasks and " Good Friends " type task of social TI. The purpose was to study TI processes under different levels of consciousness, and to discover deeper the cognitive processes and mechanism of TI. Experiment 2 is in the second part. Subjects were also undergraduate students, and materials were almost the same as experiment 1. It was about to investigate TI processes under various levels of difficulty, and to discover the cognitive processes and mechanism of TI. Experiment 3 belongs to the third part. With children subjects aged between 3 and 7, we specifically studied the development of inference ability, the velocity of development and the development of strategy, when they tried to solve these three TI tasks. This was an exploratory study on the development of the tasks above. The fourth part is experiment 4. With undergraduate subjects, we applied ERP technique to investigate the ERPs induced by TI tasks of those three types, and confirmed the unknown brain parts participating in TI by using dipole source analysis, trying to discuss the neural mechanism of TI initially.In the first part, we studied the cognition and mechanisms of three types of TI process, and the influence of different levels of consciousness on solving the TI. Research Purposes: (1) To investigate subjects's TI processes, by controlling the certainty levels of TI systematically, namely TI situations between negative and certain. Strategies used in each level of TI were also studied. (2) To investigate the regular patterns, strategies, especially the cognitive mechanisms of TI by controlling consciousness levels of TI's premise items systematically. Methods: Applying the classical transitive task and "Good Friends" task, we explored TI's processes and strategies of 81 undergraduate students, whose consciousness levels towards premise items were tested after experiment. Results: (1) Generally speaking, different types of TI needed different levels of cognitive ability. Among the three types of TI, the ability of social TI was most highly developed, followed by negative TI, and the real TI was the lowest. (2) In general, towards the consciousness levels and relations of premise items, the mechanisms and effects differed in three types of inference. In real TI, individuals performed better as consciousness level increased. Though the difference of consciousness levels was not significant, similar trend still appeared in social TI: As consciousness level increased, the correct rate of problem-solving and the pass rate went higher. In the negative TI, its mechanisms and effects were similar to the social TI. Reaction time decreased as consciousness level increased. (3) Participants used different strategies when solving different TIs. In social TI, no significant strategy preference existed. In negative TI, participants mainly used knowledge-experience strategy. Logical reasoning and knowledge-experience strategy were more preferable under high level and partial level consciousness to assuming illustration strategy. In the unconscious condition, no strategy preference exists. (4) Subject division of arts and science had no significant effect on correct rate, pass rate, reaction time and strategy-applying when sorting out three types of TI problems.In the second part, using the similar paradigm of part one, we aimed at exploring the influence of task difficulty on TI. With "Good Friends" tasks of the real, and social TI, we sought to investigate the inference processes under different degrees of difficulty levels, and went deeper to explore the cognitive processes and mechanisms of transitive inference. Research Purposes : (1) To discuss the characteristics and regular patterns of individuals' TI problem-solving ability, velocity and strategy-applying again. (2) To explore the influence of task difficulty on the individuals' TI problem-solving ability and velocity. (3) To explore the influence of task difficulty on the individuals' TI problem-solving strategies-applying. Method: Applying the transitive task paradigm and "Good Friends" task, we explored TI's processes and strategies of 73 undergrauate students, who were required to estimate the difficulty of tasks after experiment. Results: (1) In general, different types of TI required different levels of inference ability. To the ability of problem-solving, the real TI was weaker than the social one, which had similar ability pattern to the part one. However, as to the velocity, the real TI was faster than the social one significantly. (2) Generally speaking, as estimated difficulty increased, the correct rate of problem-solving of various kinds of TI decreased. There was a decreasing trend on correct rate when individuals solved two types of TI. As to the reaction time, the difference among the three difficulty levels of two types of TI was not significantly, however, the reaction time of social TI was longer than the real one. (3) Individuals primarily used three kinds of strategies when resolving different types of TI: logical reasoning, knowledge experience and assuming illustration. The strategies were flexible when estimated difficulty changed its degrees. Under the same degree of difficulty circumstances, individuals had a similar strategy-using trend. In terms of the frenquency of using same strategy, logical reasoning and knowledge experience strategies were similar when applied to different types of TI and degrees of difficulty levels. The frequency of using assuming illustration strategy was flexible in two different types of TI and three kinds of difficulty levels. It would have applying preference especially when the difficulty of real TI was harder than the social one. (4) Subject division of arts and science had no significant influence on correct rate, pass rate, reaction time and strategy preference etc.The third part primarily studied the development of ability, velocity and strategy of children aged between 3 and 7 resolving these three types of transitive inference tasks, which is an exploratory research on the development of the tasks above. Research Purposes : (1) To explore the developmental characteristics and the regular patterns of problem-solving of three types of transitive inference (real transitive inference, social transitive inference, and negative transitive inference). (2) To explore the age characteristics of children when resolving these three types of transitive inference. (3) To explore children's different types of Strategy and its developmental regular pattern when solving these three types of transitive inference questions. Methods: Applying the classical transitive task and "Good Friends" task, we examined 139 children (one by one) aged 3-7 years old with some pictures. Recording the right/wrong results and the oral reports of problem-solving strategies. Results: (1) Three different types of transitive inference had developmental trends and regular patterns of their own. Real TI was the fastest-developing one, social TI second, negative TI the slowest. The abilities to solve three types of inference task were developing as their ages growing, however, there was an obvious applying preference in three-item series questions of different ages and tasks. Some abilities displaying in those types of task sprouted, developed, and matured late and slowly, on the contrary, others developed early and fast. For three types of inference, Children's abilities developed differently: different developmental starting points, rapid developmental periods and initial forming periods. (2) Age was an important factor influencing the development of three transitive inference abilities. Age factor affected subjects' ability and speed in problem-solving. (3) Children aged 3-7 mainly used strategies like guessing, visual judgment, orientation response, experience reasoning and logical reasoning when solving three types of TI questions. Children of different ages mainly used different strategies. Some strategies were dominent when used in an early stages of children development, other strategies were replacing the early one though applied late. In different reasoning types, for each strategy, the developmental velocity of visual judgment, orientation response, and experience reasoning were relatively the same. The logical reasoning was an only exception, which developed faster in real TI, but slower in social TI.The fourth part focused on the research of neural mechanism of real TI, social TI, and negative TI. Research Purposes: (1) To analyze the ERPs induced by TI of different types initially, and study the time-process changes in different TI processes. (2) To confirm the unknown brain parts participating in the TI processing initially by using dipole source analysis. (3) To try to reveal the neural mechanism of TI. Methods: This research revealed TI's neural mechanisms of 16 right-handed undergraduate subjects, using the technique of ERP to record ERPs induced by three different types of TI that had similar stimulus form. The research tasks included traditional TI task and the newly-developed "Good Friends" TI task. Conclusions: (1) The ERPs trends induced by real, social and negative TI tasks were similar, though existing a little waveform difference—during time window of 180-260ms, these three tasks all appeard a P2, with difference on amplitude. During 300-380ms, three inference tasks all had a P3, with difference in amplitude too. Then all tasks induced a LPC. These ERPs represented the premise item recognizing, relation integration, and inference judgment process. (2) The activation differences between each TI task and its corresponding baseline had similar characteristics—at P2 the difference between baseline and inference task had no significant difference, which meant they had an identical recognizing process. The difference at P3 between baseline and inference task implied the difference of relation integration. Difference in LPC was not significant, which indicated they had the same judging process. (3) The dipole source analysis localized the generator of the differential wave of social TI and its baseline within 180-260ms in posterior cingulate and Brodmann area 23. Within the time window of 870-920ms, generator of differential waves of social TI and its baseline were mainly localized in the left temporal lobe and fusiform gyrus.