Young children's understanding of other's mental states: Using robot illustrations

本研究は，イラストを使った人間の行動とロボットの行動を比較することを通して，幼児期における他者の心の理解の発達を検討したものである。45人の幼児に，人間版とロボット版の誤信念課題と道徳判断課題を提示した。人間版とロボット版では，主人公が人間であるかロボットであるかの違い以外はすべて同じ状況で同じ行動とした。その結果，誤信念課題においては，ロボット版の方が人間版より得点が有意に低く，幼児は｢ロボットに対して，人間に対する時ほどには誤信念を考慮しない｣という傾向が明らかになった。道徳判断課題では，作為的な状況であれ不作為的な状況であれ，ロボットの行動と人間の行動の悪さの比較に差はなく，ロボットの行為に対しても，人間の行為に対してと同様の道徳判断をしたことが示唆された

Dual Biosynthesis Pathway for Longer-Chain Polyamines in the Hyperthermophilic Archaeon Thermococcus kodakarensis▿ †

Long-chain and/or branched-chain polyamines are unique polycations found in thermophiles. Cytoplasmic polyamines were analyzed for cells cultivated at various growth temperatures in the hyperthermophilic archaeon Thermococcus kodakarensis. Spermidine [34] and N4-aminopropylspermine [3(3)43] were identified as major polyamines at 60°C, and the amounts of N4-aminopropylspermine [3(3)43] increased as the growth temperature rose. To identify genes involved in polyamine biosynthesis, a gene disruption study was performed. The open reading frames (ORFs) TK0240, TK0474, and TK0882, annotated as agmatine ureohydrolase genes, were disrupted. Only the TK0882 gene disruptant showed a growth defect at 85°C and 93°C, and the growth was partially retrieved by the addition of spermidine. In the TK0882 gene disruptant, agmatine and N1-aminopropylagmatine accumulated in the cytoplasm. Recombinant TK0882 was purified to homogeneity, and its ureohydrolase characteristics were examined. It possessed a 43-fold-higher kcat/Km value for N1-aminopropylagmatine than for agmatine, suggesting that TK0882 functions mainly as N1-aminopropylagmatine ureohydrolase to produce spermidine. TK0147, annotated as spermidine/spermine synthase, was also studied. The TK0147 gene disruptant showed a remarkable growth defect at 85°C and 93°C. Moreover, large amounts of agmatine but smaller amounts of putrescine accumulated in the disruptant. Purified recombinant TK0147 possessed a 78-fold-higher kcat/Km value for agmatine than for putrescine, suggesting that TK0147 functions primarily as an aminopropyl transferase to produce N1-aminopropylagmatine. In T. kodakarensis, spermidine is produced mainly from agmatine via N1-aminopropylagmatine. Furthermore, spermine and N4-aminopropylspermine were detected in the TK0147 disruptant, indicating that TK0147 does not function to produce spermine and long-chain polyamines