Intellectual, psychical, physical, psychological, physiological, mental & spiritual comparisons.
The exact & precise psychological, , mental & spiritual comparison between the People of Other yugas and Kaliyuga is provided in Shreemad Bhagvat Purana. Book 2 , Skandha 12 ,Chapter 3 (Dharma Of kaliyuga)
Here is the comparison (relative incapabilities of Kaliyuga people) -:
संतुष्टा: करुणा मैत्रा: शान्ता दान्तास्तितिक्षव: |
आत्माराम: समदृश्य: प्रयाश: श्रमणा जना : ||१९||
santuṣṭāḥ karuṇā maitrāḥ śāntā dāntās titikṣavaḥ
ātmārāmāḥ sama-dṛśaḥ prāyaśaḥ śramaṇā janāḥ
The people of Satya-yuga are for the most part self-satisfied, merciful, friendly to all, peaceful, sober and tolerant. They take their pleasure from within, see all things equally and always endeavor diligently for spiritual perfection. SB 12.3.19
तदा क्रियातपोनिष्ठा नातिहिंस्त्रा न लंपट: |
त्रैवर्गिकास्त्रयीवृद्धा वर्णा ब्रह्मोत्तरा नृप ||२१|
tadā kriyā-tapo-niṣṭhā nāti-hiṁsrā na lampaṭāḥ
trai-vargikās trayī-vṛddhā varṇā brahmottarā nṛpa
In the Tretā age people are devoted to ritual performances and severe austerities. They are not excessively violent or very lusty after sensual pleasure. Their interest lies primarily in religiosity, economic development and regulated sense gratification, and they achieve prosperity by following the prescriptions of the three Vedas. Although in this age society evolves into four separate classes, O King, most people are brāhmaṇas.SB 12.3.21
यशस्विनो महाशाला: स्वाध्यायाध्ययने रत: |
आढया: कुटुम्बीनो हृषटा वर्णा: क्षत्रद्विजोत्तरा: ||२३||
yaśasvino mahā-śīlāḥ svādhyāyādhyayane ratāḥ
āḍhyāḥ kuṭumbino hṛṣṭā varṇāḥ kṣatra-dvijottarāḥ
In the Dvāpara age people are interested in glory and are very noble. They devote themselves to the study of the Vedas, possess great opulence, support large families and enjoy life with vigor. Of the four classes, the kṣatriyas and brāhmaṇas are most numerous.SB 12.3.23
तस्मिल्ल्लुब्धा दुराचारा निर्दया: शुष्कवैरिण: |
दुर्भगा भूरितर्षाश्र्च शुद्रदाशोत्तरा: प्रजा: ||२५||
tasmin lubdhā durācārā nirdayāḥ śuṣka-vairiṇaḥ
durbhagā bhūri-tarṣāś ca śūdra-dāsottarāḥ prajāḥ
In the Kali age people tend to be greedy, ill-behaved and merciless, and they fight one another without good reason. Unfortunate and obsessed with material desires, the people of Kali-yuga are almost all śūdras and barbarians.SB 12.3.25
Apart from what's being said in the above answer here is what i would like add.
Kaliyuga's Dharma Shastra(Smriti) is considered to be the Parashara Smriti which mentions some peculiarities of Kali Yuga and of the persons living in that age.
Self-mortification is the rule in the Krita age ; knowledge is said (to be the same) in the Treta ; in the Dvapara, (they) say sacrifice (to the gods to be) the sole (rule) ; and charity alone in the Kali age.
Parashara Smriti Chapter 1 Verse 23
So,what this verse implies is that the Kali people are not fit for extreme Tapas etc.Charity is most suitable for them.
Similarly,its stated that the Kali Yuga people derive their energy from their food only(the same thing has been stated in other Scriptures too eg-The Mahanirvana Tantram).So,fasting is not recommended for them.
Life in the Krita has its seat in the bones ; in the Treta it has its seat in the flesh ; in the Dvapara the blood is the seat of life ; in the Kali, however, life is dependent upon food and the like.
Parashara Smriti Chapter 1 Verse 32
The Mahanirvana Tantra also provides description for the people of (the 4 yugas including those of) Kali in its first chapter.The description is quite similar to the ones given in Swiftpushkar's answer.
Now the sinful Kali Age is upon them, when Dharmma is destroyed, an Age full of evil customs and deceit. Men pursue evil ways. The Vedas have lost their power, the Smritis are forgotten, and many of the Puranas, which contain stories of the past, and show the many ways (which lead to liberation), will, O Lord! be destroyed. Men will become averse from religious rites, without restraint, maddened with pride, ever given over to sinful acts, lustful, gluttonous, cruel. heartless, harsh of speech, deceitful, short-lived, poverty-stricken, harassed by sickness and sorrow, ugly, feeble, low, stupid, mean, and addicted to mean habits, companions of the base, thievish, calumnious, malicious, quarrelsome, depraved, cowards, and ever-ailing, devoid of all sense of shame and sin and of fear to seduce the wives of others. Vipras will live like the Shudras, and whilst neglecting their own Sandhya will yet officiate at the sacrifices of the low. They will be greedy, given over to wicked and sinful acts, liars, insolent, ignorant, deceitful, mere hangers-on of others, the sellers of their daughters, degraded, averse to all tapas and vrata. They will be heretics, impostors, and think themselves wise. They will be without faith or devotion, and will do japa and puja with no other end than to dupe the people. They will eat unclean food and follow evil customs, they will serve and eat the food of the Shudras and lust after low women, and will be wicked and ready to barter for money even their own wives to the low. In short, the only sign that they are Brahmanas will be the thread they wear. Observing no rule in eating or drinking or in other matters, scoffing at the Dharmma Scriptures, no thought of pious speech ever so much as entering their minds, they will be but bent upon the injury of the good (37-50). By Thee also have been composed for the good and liberation of men the Tantras, a mass of Agamas and Nigamas, which bestow both enjoyment and liberation, containing Mantras and Yantras and rules as to the sadhana of both Devis and Devas.
Advantages of being born in Kali Yuga :
Although there are many disadvantages,yet the Maharishis are full praise of Kali Yuga simply because of the fact that the path of realization(liberation) has been supposedly made simpler for the age.
It is believed that in Kali Yuga simple Nama Sankeertana (chanting of God's holy names or nama japa) is capable of giving mukti.And such an easy way of liberation was not present in the previous yugas.
In what follows i will be quoting from the book Essence of Dharma Bindu :
Vishnu Purana: Sarve Brahma vadavyanti sampraptetun Kaloau yuge, Naanu tishthanti Maitreya shishnodara parayanaah| Yada yadaasataam haanih Vedamargaanu saarinaam, Tadaa tadaa Kaler - vriddhih anumeyaa vichakshanaih|| Veda Vyaasauvaacha: Yatkrute dashabhirvarshaih tretaayaam vaayanenatu Dvaapare tacchamaasena hyahoraatrena tatlalou| Dhyaayan Krite yajan yagjnaih Tretaayaam Dwapare archayan, Yadaapnoti tadaapnoti Kalou samkeerta Keshavam/ Naaradiye/ Hare Keshava Govinda Vaasudeva Janaarddana, Iteetayanti nityam sahitaan badhate Kalih || Shiva Shankara Rudreti Nilakantha Trilochana, Iteerayanti ye nityam sahitaan baadhate Kalih/ Shiva Shankara Rudreti Neelakantha Trilochana, Iteerayanti ye nityam sahitaan baadhate Kalih||
Vishnu Purana details Yuga dharmas as follows: In Kali Yuga, every one discusses about Brahma Jnaana but none is really interested in it since they are overwhelmed of selfishness, centric pysche and sex but none really is serious in favour of Brahma Jnaana; as and when there occurs a danger to the Virtuous, there is the upgradation of evil forces and infringement of virtue, and the signs of Kali Yuga become prominent and clear.
The rewards of virtue by of Tapas during Krita Yuga are as good as Yagnas in Treta yuga, worships in Dvapara Yuga and even ‘Samkeertanas’ rendering Sacred Songs in Kali yuga.
Similarly Narada says:
Narada Brahmarshi states that the soulful singing of Narayana as: Here Keshava Govinda Vaasudeva Janardana
Iteerayanti nityam sahitaan baadhate Kalih. Or alternatively as Shiva Shankara Rudreti Neelakantha Tricochana, Itirtayanti ye nityam sahitaan baadhate Kalih ||
That is either render Hari Smarana or Hara smarana as above! Kali Yuga would never ever torment sincere prayers with the naamas as mentioned above. Such indeed are the Yuga Dharmas!
Narada Brahmarshi states that the intensity of Kali Yuga is gradually diminished with Nitya Keertana: Shiva Shankara Rudresha Neelakantha Trilochana, Iteerayantiye nityam na Kalirbhaadhyate chataan/ Mahadeva Virupaksha Gangaadhara Mridaavyaya, Iteeranti ye nityam te kritaadhona shamshayah||
Nitya keertana of ‘Shiva Shankara Rudresha Neelakantha Trilochana’ or ‘Mahadeva Virupaaksha Gangaadhara Mrida - avyaya’ assuages the severity of Kali Yuga, reduces its impact and bestows fulfillment of one’s life!
Also, as per the Bhavisya Purana ,the people living in Kali Yuga will not only be short-lived but their heights will also be short.And it will get even shorter as the Yuga progresses.
Over two thousand years, the established Regulations made by Lord Brahma and the successive Manus would get thinner and thinner and by the Second Paada of Kali Yuga, Kali Devata would be happy to witness that the old Vedic values would be obliterated, that the Daityamaya human beings (fully soaked in Daitya activities) would be of two-and-half feet height, that their life span would be forty years maximum (as against hundred years now) and that they would be free like birds without any Karmic regulations!