A Game Theoritic Analysis of Polygyny

by Berly

We will discuss the current hot topic in Indonesia (Hollywood already has a TV series onthe topic since early this year) in economics context. I will employ game theory as tool of analysis since it involves strategic interaction and the payoff depend on other people’s response. (for quick review click here)

The etymologically correct term is polygyny since polygamy is the case with multiple spouses for both genders (the term for one woman with many husband is polyandry).

Let lay out the assumptions. I assume common knowledge (structure and payoff) and reveal preference (the husband will tell truthfully whether he wants poliginy and the wife will tell truthfully whether she accept it or not).

I don’t know how to draw the game tree in blogspot so verbal description should do.

It is a two stage game where on the first stage the husband decides whether to do polygyny and tell his wife. I will only discuss the case of husband with poligyny inclination since otherwise nothing happened and the couple stay monogamous. On the second stage the wife decide whether to accept her husband intention to do polygyny or not.

For husband the preference in descending order is polygyny, monogamiy (with first wife) and divorce first wife to marry the incoming woman (before receiving complains, this condition not apply to all men/husbands). I will discuss the wife's preference a bit later.

Since the husband strictly prefer polygyny to divorcing the first wife to marry the incoming woman then the first wife could threat for divorce if she don’t want poligyny. The husband cancels his intention and they stay monogamous.

Why this is not always the case? The threat is not credible if the husband know the first wife’s preference is (in descending order) monogamous, polygyny & divorce. Meaning the husband know the wife in the end will choose to accept the second marriage than get divorce and be a widow.

The financial struggle of non-working women to get new job after long unemployed is an uphill struggle. There is also problem of society looking down on widows and the difficulty to get new husband after divorce.

First wife everywhere! You can, paradoxically, prevent your husband (if he has the inclination) from conducting polygyny by credibly demonstrating your willingness to divorce him.

So get a good job with decent salary, keep the social network (in case you need better job/ husband) and staybeautiful. You will keep your husband of yourself as long as you want him (caveat, if the assumptions used above are applicable in your case).

More economics of polygyny by our Anglo-Saxon friends here (I also recommend this and this movie for weekend).

Tragedy of The Commons: Downloading Movie

by Alief

Salah satu hal yang paling kami (Norway's Folks, saya+kak dewa) banggakan di student housing NULS adalah fasilitas internet 24 jam, 7 hari seminggu, 10 Mbps di kamar masing-masing. Semua jadi indah karena hampir semua bisa kita dapatkan di dunia maya ini. Dari mengunduh jurnal - jurnal yang dilanggan oleh kampus, sampai dengan tindakan - tindakan ilegal khas negara berkembang, mengunduh lagu, majalah dalam format pdf dan yang paling menyenangkan FILM baru. Pernah suatu masa kak Dewa dengan bangga bercerita, di kala Star Wars paling baru belum tayang perdana, dia sudah asyiknya menonton hasil mengunduh di internet. Saya rasakan kegembiraan itu juga akhirnya disini, semua film baru, sebut apa saja, mulai Harry Potter-Goblet of Fire, The Chronicles of Narnia, sampai terakhir Munich, kami tonton dengan kualitas DVD dengan cara yang sama.

Tentu, kami bayar sewa bulanan flat yang termasuk di dalamnya fasilitas internet tanpa batas ini. Dan sebagai orang timur yang suka berbagi kebahagiaan, kadang kala saya membagi informasi cara mengunduh ini kepada teman - teman flat satu gedung. Saya mengira informasi ini layak dibagi karena dia adalah public goods. Suatu kebodohan, karena saya baru menyadari bahwa informasi ini berada di posisi common goods.

Ekonom mengelompokkan barang berdasarkan sifat rivalry dan excludability (mungkin ada yang bisa menemukan padanan kata yang tepat di bahasa Indonesia?). Jika ia secara bersamaan rivalry dan excludability, ia adalah private goods. Jika ia bersamaan non rivalry dan non excludability dia jadi public goods (contoh:TNI, Polisi). Yang sumir diantaranya sedikit rumit: rivalry saja tapi non excludable disebut common goods (contoh: SDA), dan excludability saja-non rivalry disebut club goods (contoh: klub). Awam, seringkali club goods dan common goods dimasukkan ke dalam public goods.

Kembali ke cerita, informasi tentang film gratis ini mengundang banyak orang untuk ikut bergabung dan memaksimalkan konsumsi. Beban jaringan gedung makin lama makin besar, dan bulan ini jaringan harus putus beberapa kali karena overload. Ekonom percaya there is no free lunch, sesuatu yang nyaris gratis ternyata harus dibayar dalam bentuk lain, dalam hal ini jaringan yang putus dan, untuk saya pribadi, kesal luar biasa karena saya berasa jadi ekonom paling bodoh sedunia.

Namun pengalaman saya adalah hal kecil dibanding tragedi kemanusiaan dalam Tragedy of Easter Island yang mengilhami paper terkenal Tragedy of the Commons. Keterbatasan sumber daya alam, populasi yang meningkat, dan kesalahan memposisikan sumber daya alam dalam perekonomian membuat penduduk satu pulau punah setelah sebelumnya terjadi kanibalisme untuk bertahan hidup.

Ah, saya baru sadar arti mimpi saya beberapa hari ini. Ada orang tak henti - hentinya mentertawakan saya. Mungkin dia Thomas Robert Malthus...